synthesis methods | synthesis principle | advantages | disadvantages |
---|
physical method | Physical method for the AgNPs synthesized by using physical energy to harvest AgNPs with a narrow size distribution. | Radiation is used as a reducing agent, so no dangerous chemicals involved produce a large number of silver nanoparticles in a single process within a short time. The silver nanoparticles produced are contamination-free and do not need further purification. | Expensive, less yield along with high consumption of energy, contamination of solvent, and random distribution. |
chemical method | Silver ions reduce to the silver atoms by using chemical reducing agents. | Simple production, economics, and high yield. | Less use of capping agents for AgNP synthesis is toxic and hazardous; the manufactured particles require further purification as their surfaces are contaminated with chemical sediments; lack of regular sizes; require more steps to stop self-aggregation; and the release of hazardous byproducts during synthesis. |
photochemical method | By using photochemically generated intermediates, production of metal course and reduction of metal ions. | A clean process with good spatial resolution and convenience. | High costs and experimental environment are required. |
biological method | The reduction of silver ions to silver atoms by using biomolecules is derived from living organisms. | Cost-effective and abundance of raw materials. | |
Figure 1. Different methods of AgNPs synthesis.
Green Route for AgNP Synthesis
Plant extracts used for agnp synthesis, preparation of plant extract.
method | procedure | extraction solvent | volume consumed | extraction time | extraction temperature | extraction efficiency |
---|
maceration | Powdered plant material is dissolved in solvent in a closed vessel for a long time with occasional shaking, filtered to obtain extract, and evaporated. | water, aqueous, and nonaqueous solvents | large | long (hours to days) | room temperature | low |
Soxhlet extraction | Plant material loaded in a thimble is extracted by continuous hot extraction in a Soxhlet extractor. | organic solvents | moderate | long | under heat | moderate |
pressurized liquid extraction | Plant material with solvent is heated above boiling point under high pressure. | aqueous or organic solvents | less | less (5–10 min) | under heat and pressure | high |
supercritical fluid extraction | Supercritical fluid, mainly CO , is used for plant extraction. | very little amount of organic solvent or no solvent | less | less | heated to supercritical conditions | high |
microwave-assisted extraction | Plant material with appropriate solvent is packed into a microwave-assisted extractor. | mainly polar solvents | less | less (15–20 min) | under heat generated by conversion of microwave radiation | high |
ultrasound-assisted extraction | Plant material with appropriate solvent is packed into an ultrasonic water bath. | | less | less | under heat generated by the conversion of ultrasonic radiation | high |
Stepwise Procedure for AgNP Synthesis by Using Plant Extracts
Fresh, healthy, and mature plant parts are selected and washed frequently with tap water followed by deionized water to remove surface contaminants.
Cleaned plant parts are sliced into fine pieces, air-dried in the shade for several days or at a definite temperature in a hot air oven for a definite time, and pulverized into fine powder.
Powdered plant material can then be extracted with water or organic solvents by following different techniques, such as simple boiling for some minutes, microwave- and ultrasound-assisted extraction, etc.
The extract is vacuum-dried and concentrated using a rotary evaporator.
The plant extract is mixed with a definite amount of silver nitrate (AgNO 3 ) solution in the ratio of 1:9.
The reaction mixture is then kept undisturbed until a reddish-brown color forms from the colorless AgNO 3 solution. This indicates the formation of AgNPs. This process can be carried out at room temperature or varying temperatures as per requirements.
The free particles are then washed and purified by centrifugation.
To eliminate extra silver ions, the silver colloids are washed multiple times with deionized water.
Further, the AgNPs so prepared are lyophilized and kept in tight-packed vials under ambient conditions for their characterization and application.
Figure 2. Generalized method for AgNP synthesis by using plant extracts.
Mechanism of AgNP Formation by Using Plant Extract
Figure 3. Mechanism of AgNP formation by using plant extracts.
Factors Affecting AgNP Synthesis by Using Plant Extracts
Synthesis of silver nanoparticles using amino acids.
Figure 4. Chemical structures of common sugars, polysaccharides, and amino acids found in plant extracts.
Analytical Techniques for the Characterization of AgNPs
Ftir spectroscopy.
Figure 5. Schematic diagram of FTIR.
Figure 6. Analyses of the FTIR spectrum of leaf extracts of Eichhornia crassipes (reprinted with permission from ref (84) ).
Figure 7. Infrared spectra of ginger extract (A) and silver nanoparticles produced using ginger extract (B) (reprinted with permission from ref (86) ).
UV–Visible Spectroscopy
Figure 8. Schematic diagram of the UV–visible spectrophotometer.
Figure 9. Using Cyprus rotundas, the UV–visible spectrum of AgNPs (reprinted with permission from ref (95) ).
Figure 10. UV–visible absorption spectra of green synthesized AgNPs made with an aqueous Peganum harmala leaf extract (reprinted with permission from ref (96) ).
Figure 11. Absorption spectra of produced AgNPs in the ultraviolet–visible range utilizing ginger extract (reprinted with permission from ref (86) ).
Nuclear Magnetic Resonance (NMR) Spectroscopy
X-ray diffraction.
Figure 12. XRD spectra of AgNPs produced with G. resinifera at various precursor concentrations (reprinted with permission from ref (98) ).
Scanning Electron Microscopy (SEM)
Figure 13. Schematic diagram of SEM.
Figure 14. (a) R. glutinis AgNP SEM image and (c) size histogram. (b) R. mucilaginosa AgNP SEM image and (d) size histogram (reprinted with permission from ref (122) ).
Transmission Electron Microscopy (TEM)
Figure 15. Schematic diagram of TEM.
Nanoparticle–Biomolecule Interaction
Figure 16. Interaction of AgNPs with biomolecules.
Potential Biological Activities of Plant-Based AgNPs
plant species | parts used | extraction technique | bioactive components | agnps specification | potential application | reference |
---|
| stem bark | Soxhlet extraction with water. | amino acids, carbohydrates, alkaloids, tannins, glycosides, flavonoids, and steroids | polydispersed, sphere-shaped, 17–29 nm | antibacterial activity | |
| leaves, flower, and stem | Boiled with water at 60 °C for 15–20 min with constant shaking. | | polydispersed, sphere-shaped, 88.11 nm | antibacterial activity | |
| tuber | Macerated with methanol for 4 days. | phenolic compounds | sphere-shaped, 5–8 nm | antibacterial activity | |
| aerial part | Boiling with 50% ethanol at 60 °C for 10 min. | flavonoid and phenolic acids | sphere-shaped, 5–25 nm | antibacterial, antioxidant, and cytotoxic activity | |
| leaf | Boiling with water at 85 °C for 60 min with continuous stirring at 200 rpm. | | sphere-shaped | anticancer, anti-inflammatory, and antioxidant activity | |
| leaf | Maceration with 70% methanol. | phenolics and flavonoids | sphere-shaped, 3–6 nm | antibacterial activity and anticancer activity | |
| flower | Simple boiling with water for 5 min. | flavonoids, terpenoids, and glycosides | polydispersed, sphere-shaped, 37.71–71.99 nm | antibacterial activity, lactate dehydrogenase (LDH) activity, and no cytotoxic activity | |
| leaf | Simple extraction with cold water followed by centrifugation. | alkaloids and flavonoids | polydispersed, cuboidal, and rectangular-shaped, 15–65 nm | antibacterial activity. | |
| leaf | Simple boiling with water for 30 min followed by centrifugation. | iridoids, flavonoids, phenolic acids, and etheric oils | quasi-sphere-shaped, 40.37 ± 1.8 nm | anticancer activity, antibacterial activity, and antibiofilm activity | |
| stem bark | Boiled with ethanol. | | | scavenging, antiurolithiatic, and antidiabetic activity | |
| leaf | Macerated with ethanol (98%) for 24 h with shaking at room temperature. | essential oils, phenolics, terpenoids, and flavonoids | sphere-shaped, 23.4–53.2 nm | scavenging, antibacterial, antifungal, and anti-inflammatory activity | |
| root | Ultrasound-assisted extraction with 70% ethanol. | | spherical and irregularly shaped, 12–15 nm | antibacterial activity | |
Conclusions and Future Directions
Author information.
- Nitin Kumar Sharma - Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India ; Shri Maneklal M. Patel Institute of Sciences and Research, Kadi Sarva Vishwavidyalaya, Gandhinagar 382023, India ; Email: [email protected]
- Taghrid S. Alomar - Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia ; Email: [email protected]
- Najla AlMasoud - Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia ; Email: [email protected]
- Jyotsna Vishwakarma - K. B. Pharmacy Institute of Education and Research, Kadi Sarva Vishwavidyalaya, Gandhinagar 382023, India
- Summi Rai - Department of Chemistry, Mahendra Morang Adarsh Multiple Campus, Tribhuvan University, Biratnagar 56613, Nepal
- Notes The authors declare no competing financial interest.
Acknowledgments
N.K.S. acknowledges the Science and Engineering Research Board, Government of India, grant no. SERB/CHE/2021412 for funding. We also express our sincere gratitude to Shri Maneklal M. Patel Institute of Sciences and Research, Kadi Sarva Vishwavidyalaya, Gandhinagar, Gujarat, India for providing necessary facilities.
This article references 161 other publications.
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- 7 Rahman, A. U. ; Khan, A. U. ; Yuan, Q. ; Wei, Y. ; Ahmad, A. ; Ullah, S. ; Khan, Z. U. H. ; Shams, S. ; Tariq, M. ; Ahmad, W. Tuber Extract of Arisaema Flavum Eco-Benignly and Effectively Synthesize Silver Nanoparticles: Photocatalytic and Antibacterial Response against Multidrug Resistant Engineered E. Coli QH4 . Journal of Photochemistry and Photobiology B: Biology 2019 , 193 , 31 – 38 , DOI: 10.1016/j.jphotobiol.2019.01.018 Google Scholar 7 Tuber extract of Arisaema flavum eco-benignly and effectively synthesize silver nanoparticles: Photocatalytic and antibacterial response against multidrug resistant engineered E. coli QH4 Rahman, Aziz Ur; Khan, Arif Ullah; Yuan, Qipeng; Wei, Yun; Ahmad, Aftab; Ullah, Sadeeq; Khan, Zia Ul Haq; Shams, Saira; Tariq, Muhammad; Ahmad, Waqas Journal of Photochemistry and Photobiology, B: Biology ( 2019 ), 193 ( ), 31-38 CODEN: JPPBEG ; ISSN: 1011-1344 . ( Elsevier B.V. ) Biogenic silver nanoparticles (AgNPs) from three fractions of Arisaema flavum tuber ext. were synthesized and characterized by UV-visible spectroscopy, XRD (X-rays diffraction), FT-IR (Fourier transform IR spectroscopy) TEM (transmission electron microscopy) and EDX (Energy dispersive Microscopy). XRD pattern show the fcc. cryst. (Fcc) structure of AgNPs. FTIR spectra confirmed the presence of different Polyphenolic compds. capping the AgNps. UV-visible spectroscopy result confirmed the presence of Ag because of the particular surface plasmon Resonance (SPR) in the area of 400-430 nm. The electron microscope studies revealed the formation of spherical AgNPs with diam. ranging from 12 nm to 20 nm. Strong signals of AgNPs were confirmed with EDX anal. The antibacterial properties of the AgNPs prepd. with various exts. were tested against multi-drug resistant bacteria. Which showed significant antibacterial activity against all the multidrug resistant bacterial strains and esp. multidrug resistant engineered E.ColiQH4. AgNPs synthesized by methanolic, Et Acetate and aq. Exts. of Areseama Flavum exhibited significant Photocatalytic activity to reduce methylene blue. Small size, spherical shape and high dispersion are the key properties due to which the AgNPs are having significant biol. and photocatalytic activity. To the best of our knowledge, it is the first report of biogenic AgNPs regarding antibacterial activity against multidrug resistant Engineered E.Coli QH4. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXjs1Gksb8%253D&md5=477cfccd0644d9833c64ee2d865ed36f
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- 9 Singh, D. ; Chaudhary, D. ; Kumar, V. ; Verma, A. Amelioration of Diethylnitrosamine (DEN) Induced Renal Oxidative Stress and Inflammation by Carissa Carandas Embedded Silver Nanoparticles in Rodents . Toxicol. Rep. 2021 , 8 , 636 – 645 , DOI: 10.1016/j.toxrep.2021.03.014 Google Scholar 9 Amelioration of diethylnitrosamine (DEN) induced renal oxidative stress and inflammation by Carissa carandas embedded silver nanoparticles in rodents Singh, Deepika; Chaudhary, Deepak; Kumar, Vikas; Verma, Amita Toxicology Reports ( 2021 ), 8 ( ), 636-645 CODEN: TROEF9 ; ISSN: 2214-7500 . ( Elsevier B.V. ) Inflammation and oxidative stress are the main factors ascribed with interruption in the process of renal tissue impairment. The toxicity of different types of nitrosamine is well recognized in animals and humans. Administration of the smallest quantities of diethylnitrosamine or dimethylnitrosamine either orally or parenterally results into renal damage. Therapeutic effects of phytofabricated silver nanoparticles of Carissa carandas aq. ext. has been scrutinised in current study for the assessment of renal cancer activity in animal model. Phytofabricated silver nanoparticles were characterized by using different instrumentation. Nephroprotective activity of silver nanoparticles at different doses was evaluated against N-diethylnitrosamine (200 mg/kg b.w., i.p.) in animal model. Serum and renal homogenate were taken to evaluate the renal toxicity markers, oxidative stress, and antioxidant parameter, proinflammatory cytokines and histopathol. study. Significant outcomes of silver nanoparticles in dose dependent manner down regulated the elevated serum marker, tumor marker enzymes and histopathol. observation of repaired tissue assured the renal cancer activity in animals. In addn., profile of enzymic and non-enzymic antioxidant, proinflammatory cytokines and tumor promotion marker also favors the anticancer property of silver nanoparticles. The data of current study reveals silver nanoparticles ameliorates renal oxidative stress and carcinogenesis which was induced by N-diethylnitrosamine and accredited to antioxidant and anticancer activities of phytofabricated nanoparticles by biol. approach. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVOmurvL&md5=05b844f11e12c689dde6ba0ca54feca3
- 10 Philip, D. Honey Mediated Green Synthesis of Gold Nanoparticles . Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2009 , 73 , 650 – 653 , DOI: 10.1016/j.saa.2009.03.007 Google Scholar 10 Honey mediated green synthesis of gold nanoparticles Philip, Daizy Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy ( 2009 ), 73A ( 4 ), 650-653 CODEN: SAMCAS ; ISSN: 1386-1425 . ( Elsevier B.V. ) Bio-directed synthesis of nanoparticles is of interest to biologists, chemists and materials scientists. The biosynthesis of gold nanoparticles has been carried out by several groups of scientists by using plants, fungi and bacteria. Now a greener synthesis of Au nanoparticles is reported by using natural honey as a reducing and capping agent. By adjusting the concns. of HAuCl4 and honey in aq. solns., colloids having a larger propensity of either anisotropic or spherical nanocrystals could be obtained at room temp. The nanoparticles obtained were characterized by UV-visible spectra, high-resoln. TEM and XRD. The spherical particles obtained had a diam. of ∼15 nm as shown by XRD patterns and TEM images. The high crystallinity with the fcc. phase is evidenced by bright circular spots in SAED pattern and clear lattice fringes in the high-resoln. TEM image. FTIR measurements were carried out to identify the possible biomols. responsible for capping and efficient stabilization of the Au nanoparticles synthesized using honey. The carboxylic acid group vibrations and amide I and II bands indicate the binding of protein with Au surfaces through the amine group rather than the carboxyl group. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnt1emtb4%253D&md5=c92e0079c884dc369aa705cf760454c0
- 11 Nidya, M. ; Umadevi, M. ; Sankar, P. ; Rajkumar, B. J. M. L-Glutamic Acid Functionalized Silver Nanoparticles and Its Nonlinear Optical Applications . Journal of Materials Science: Materials in Electronics 2015 , 26 , 4124 – 4131 , DOI: 10.1007/s10854-015-2956-9 Google Scholar 11 L-Glutamic acid functionalized silver nanoparticles and its nonlinear optical applications Nidya, M.; Umadevi, M.; Sankar, Pranitha; Rajkumar, Beulah J. M. Journal of Materials Science: Materials in Electronics ( 2015 ), 26 ( 6 ), 4124-4131 CODEN: JSMEEV ; ISSN: 0957-4522 . ( Springer ) L-Glutamic acid functionalized silver (Glu-Ag) nanoparticles (NPs) were synthesized in the aq. medium and in a sol-gel matrix. Both samples showed different UV/Vis, zeta potential, TEM and SEM profiles. Surface enhanced raman spectra of the colloidal NPs reveal that the amino moiety of Glu is bound on the Ag surface with the charged carboxylate group pointing outwards. In contrast, in the sol-gel media, the attachment of Glu to the Ag NP surface was through the carboxylate group. Intensity-dependent nonlinear optical absorption measured using the open aperture Z-scan technique revealed that the aq. soln. of Glu-Ag is an efficient optical limiter. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXlvVCnt7g%253D&md5=d5d5c0f283f7dcfd0ae95e273ca5693c
- 12 Jacob, J. A. ; Naumov, S. ; Mukherjee, T. ; Kapoor, S. Preparation, Characterization, Surface Modification and Redox Reactions of Silver Nanoparticles in the Presence of Tryptophan . Colloids Surf., B 2011 , 87 , 498 – 504 , DOI: 10.1016/j.colsurfb.2011.06.017 Google Scholar 12 Preparation, characterization, surface modification and redox reactions of silver nanoparticles in the presence of tryptophan Jacob, Jasmine A.; Naumov, Sergej; Mukherjee, Tulsi; Kapoor, Sudhir Colloids and Surfaces, B: Biointerfaces ( 2011 ), 87 ( 2 ), 498-504 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) The synthesis and characterization of water-sol. dispersions of Ag nanoparticles by the redn. of AgNO3 using tryptophan under alk. synthesis conditions are reported. The Ag nanoparticle formation was very slow at low concn. and rapid at extremes. For surface modification and redox reactions, manipulating the interparticles interaction controlled the size of Ag nanoparticles aggregates. Our results suggest that the replacement of the BH4 - ions adsorbed on the nanoparticle surface by tryptophan destabilizes the particles and further caused aggregation. A mechanism is proposed for the formation of silver nanoparticles by tryptophan. The exptl. results are supported by theor. calcns. The Ag nanoparticles were characterized by UV-vis absorption, dynamic light scattering and transmission electron microscopy techniques. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptVyhu74%253D&md5=e40a8278918d627415075cce60a101e7
- 13 Rafey, A. ; Shrivastavaa, K. B. L. ; Iqbal, S. A. ; Khan, Z. Growth of Ag-Nanoparticles Using Aspartic Acid in Aqueous Solutions . J. Colloid Interface Sci. 2011 , 354 , 190 – 195 , DOI: 10.1016/j.jcis.2010.10.046 Google Scholar 13 Growth of Ag-nanoparticles using aspartic acid in aqueous solutions Rafey, Abu; Shrivastavaa, K. B. L.; Iqbal, Sayed Aftab; Khan, Zaheer Journal of Colloid and Interface Science ( 2011 ), 354 ( 1 ), 190-195 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier B.V. ) Spectrophotometric, kinetic, and transmission electron microscopic (TEM) data for the formation of Ag-nanoparticles using aspartic acid (Asp) as reductant are reported for the first time. In the formation of transparent silver sols, an alk. medium is required. The silver nanoparticles are spherical, uniform particle size, and strongly depend on the [Asp]. The apparent rate const. decreases with [Asp] (from 4.0 to 24.0 × 10-4 mol dm-3, the rate consts. decreased from 2.6 × 10-4 to 0.3 × 10-4 s-1). For a certain reaction time, i.e., 30 min, the absorbance of the silver sol first increased until it reached a max., and then decreased with [Asp]. Kinetic and TEM results indicate that the size of the Ag-nanoparticles depends on the [Asp]. It is proposed that the oxidn. of Asp occurs by the adsorbed Ag+ ions on the surface of Ag2O particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFyis7%252FL&md5=07d368b5a24857fa4a066ff93e65f579
- 14 Khan, Z. ; Talib, A. Growth of Different Morphologies (Quantum Dots to Nanorod) of Ag-Nanoparticles: Role of Cysteine Concentrations . Colloids Surf., B 2010 , 76 , 164 – 169 , DOI: 10.1016/j.colsurfb.2009.10.029 Google Scholar 14 Growth of different morphologies (quantum dots to nanorod) of Ag-nanoparticles: Role of cysteine concentrations Khan, Zaheer; Talib, Abou Colloids and Surfaces, B: Biointerfaces ( 2010 ), 76 ( 1 ), 164-169 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) This work describes an easy chem. method for the prepn. of orange-red color silver sol by the cysteine redn. of silver (I) in the presence of cetyltrimethylammonium bromide (CTAB). The obtained sol was found to have very small particles in the order of quantum dots for the first time. Transmission electron microscope (TEM) images show that the silver sol consists of aggregated as well as crosslinking arrangement of spherical silver quantum dots (size in the range ca. ≤16 nm). In addn., the authors obsd. the changes in the morphologies of the Ag-nanoparticles from quantum dots to nanorod of diam. 60 nm and pearl-necklace shaped which occurred due to the crosslinking aggregation of silver quantum dots. For a certain reaction time, i.e., 100 min, the absorbance of reaction mixt. first increased until it reached a max., then decreased with [cysteine]. The rate of Ag-nanoparticles formation decreases with the increase in [cysteine] whereas [CTAB] and [Ag+] have no effect on the reaction rate. Interestingly, at higher [cysteine] (≥20.0 × 10-4 mol dm-3), white ppt. was formed instead of transparent silver sol. Cysteine acts as a reducing, crosslinking, stabilizing and buffering agent during the growth of different shape and size of silver nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXotlSgsA%253D%253D&md5=84ed26736d2c67c93fd131146da4c994
- 15 de Matos, R. A. ; Courrol, L. C. Biocompatible Silver Nanoparticles Prepared with Amino Acids and a Green Method . Amino Acids 2017 , 49 ( 2 ), 379 – 388 , DOI: 10.1007/s00726-016-2371-4 Google Scholar 15 Biocompatible silver nanoparticles prepared with amino acids and a green method de Matos Ricardo Almeida; Courrol Lilia Coronato Amino acids ( 2017 ), 49 ( 2 ), 379-388 ISSN: . The synthesis of nanoparticles is usually carried out by chemical reduction, which is effective but uses many toxic substances, making the process potentially harmful to the environment. Hence, as part of the search for environmentally friendly or green synthetic methods, this study aimed to produce silver nanoparticles (AgNPs) using only AgNO3, Milli-Q water, white light from a xenon lamp (Xe) and amino acids. Nanoparticles were synthetized using 21 amino acids, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by UV-Vis, zeta potential measurements and transmission electron microscopy. The synthesis of silver nanoparticles with tryptophan and tyrosine, methionine, cystine and histidine was possible through photoreduction method. Spherical nanoparticles were produced, with sizes ranging from 15 to 30 nm. Tryptophan does not require illumination nor heating, and the solution color changes immediately after the mixing of reagents if sodium hydroxide is added to the solution (pH = 10). The Xe illumination acts as sodium hydroxide in the nanoparticles synthesis, releases H(+) and allows the reduction of silver ions (Ag(+)) in metallic silver (Ag(0)). >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sjhtlCisw%253D%253D&md5=061cd69078926663ebc2e09c1231c497
- 16 Huang, Y.-F. ; Lin, Y.-W. ; Chang, H.-T. Growth of Various Au–Ag Nanocomposites from Gold Seeds in Amino Acid Solutions . Nanotechnology 2006 , 17 , 4885 – 4894 , DOI: 10.1088/0957-4484/17/19/018 Google Scholar 16 Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions Huang, Yu-Fen; Lin, Yang-Wei; Chang, Huan-Tsung Nanotechnology ( 2006 ), 17 ( 19 ), 4885-4894 CODEN: NNOTER ; ISSN: 0957-4484 . ( Institute of Physics Publishing ) In this paper, we describe an easy procedure for the prepn. of differently shaped and sized Au-Ag nanocomposites from gold nanorod (AuNR) seeds in various amino acid solns.-arginine (Arg), cysteine (Cys), glycine (Gly), glutamate (Glu), glutamine (Gln), histidine (His), lysine (Lys), and methionine (Met), resp.-at values of pH ranging from 8.0 to 11.5. Our results suggest that the pH, the nature of the amino acid, and its concn. all have significant impact on the prepn. of Au-Ag nanocomposites; these factors exhibit their effects mainly through control over the reducing ability of ascorbate and/or its recognition capability, as well as through control over the surface charges of the amino acids on the AuNRs. Depending on the value of pH, we were able to prep. I-shaped, dumbbell-shaped, and/or sphere-shaped Au-Ag nanocomposites in 0.1 M solns. of Arg, Gly, Glu, Gln, Lys, and Met. In His solns. at pH 8.0 and 9.0, we obtained peanut-shaped Au-Ag nanocomposites. Corn-shaped Au-Ag nanocomposites were prepd. in 0.1 M Met solns. (pH 9.0 and 10.0). By controlling the Lys concn. at pH 10.0, we synthesized pearl-necklace-shaped Au-Ag nanoparticles and Au-Ag wires. Based on the TEM images, we conclude that this simple and reproducible synthetic approach allows prepn. of high-quality (>87%, beside >77% in solns.) Au-Ag nanocomposites with various shapes and sizes under different conditions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1Klt7nP&md5=1efa52b3fe8ba9f149b78caa627c81d2
- 17 Mocanu, A. ; Cernica, I. ; Tomoaia, G. ; Bobos, L. D. ; Horovitz, O. ; Tomoaia-Cotisel, M. Self-Assembly Characteristics of Gold Nanoparticles in the Presence of Cysteine . Colloids Surf., A 2009 , 338 , 93 – 101 , DOI: 10.1016/j.colsurfa.2008.12.041 Google Scholar 17 Self-assembly characteristics of gold nanoparticles in the presence of cysteine Mocanu, Aurora; Cernica, Ileana; Tomoaia, Gheorghe; Bobos, Liviu-Dorel; Horovitz, Ossi; Tomoaia-Cotisel, Maria Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2009 ), 338 ( 1-3 ), 93-101 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Gold nanoparticles in aq. dispersions were prepd. by two methods, using sodium citrate as redn. agent, and their interaction with -cysteine was investigated. UV-vis, dynamic light scattering (DLS) and zeta potential measurements were used for phys. and chem. characterization of mixts. with different gold:cysteine ratios, coupled with transmission electron microscopy (TEM) and at. force microscopy (AFM) observations. Even a dild. (0.001 M) cysteine soln. leads to a rapid assembly of gold nanoparticles and a broad absorption band at longer wavelength (characteristic for the aggregation of gold nanoparticles) develops and surpasses rapidly the peak of non-aggregated gold particles. TEM images for gold nanoparticles mixed with a 0.001 M cysteine soln. show randomly arranged aggregates of gold nanoparticles on TEM carbon coated copper grids. AFM images indicate a rather ordered surface of self-assembled monolayers deposited on silanized glass. From thermodn. considerations on the protolytic equil. in aq. cysteine solns., the species present at different pH values were ascertained. A possible model for cysteine binding to gold nanoparticles and for the formation of gold particle assemblies is also suggested. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitF2ntrw%253D&md5=35645d1cdddcabebfd5f588d4c3201e1
- 18 Zare, D. ; Khoshnevisan, K. ; Barkhi, M. ; Tahami, H. V. Fabrication of Capped Gold Nanoparticles by Using Various Amino Acids . J. Exp. Nanosci. 2014 , 9 , 957 – 965 , DOI: 10.1080/17458080.2012.752582 Google Scholar 18 Fabrication of capped gold nanoparticles by using various amino acids Zare, Davood; Khoshnevisan, Kamyar; Barkhi, Mohammad; Tahami, Hamed Vakili Journal of Experimental Nanoscience ( 2014 ), 9 ( 9 ), 957-965 CODEN: JENOBX ; ISSN: 1745-8080 . ( Taylor & Francis Ltd. ) The prodn. of gold nanoparticles (GNPs) by amino acid is one of the most attractive and interesting subjects in nanobiotechnol. In this study, amino acids have been utilized as a reducing agent and also an agent for capping GNPs. The GNPs were prepd. using a redn. soln. contg. gold cations with optimum concn. of gold salt (5 mM), and also functionalised by glutamic acid, phenylalanine and tryptophan with optimum concn. of amino acids (25 mM). The optimum condition of gold soln. and amino acids were achieved by UV-visible spectroscopy. The size of nanoparticles was obtained 5-20, 10-20 and 20-30 nm, resp., by transmission electron microscopy and dynamic light scattering techniques. The results obtained from exptl. and quantum calcns. confirm that amino acids have strong bond while they have anion binding. Moreover, the free carboxylic groups of capped GNPs are one of the suitable and capable beads for binding biol. agents. As a result, the medical applications of amino acids and proteins can be used as a practical method due to the strong interaction of peripheral amine groups with nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXit1Wqtbw%253D&md5=fd8536febae3520771e98dd489bb7892
- 19 Zare, D. ; Akbarzadeh, A. ; Barkhi, M. ; Khoshnevisan, K. ; Bararpour, N. ; Noruzi, M. ; Tabatabaei, M. L-Arginine and L-Glutamic Acid Capped Gold Nanoparticles at Physiological PH: Synthesis and Characterization Using Agarose Gel Electrophoresis . Synth. React. Inorg., Met.-Org., Nano-Met. Chem. 2012 , 42 , 266 – 272 , DOI: 10.1080/15533174.2011.609855 Google Scholar 19 L-Arginine and L-Glutamic Acid Capped Gold Nanoparticles at Physiological pH: Synthesis and Characterization Using Agarose Gel Electrophoresis Zare, Davood; Akbarzadeh, Azim; Barkhi, Mohammad; Khoshnevisan, Kamyar; Bararpour, Nasim; Noruzi, Masumeh; Tabatabaei, Meisam Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry ( 2012 ), 42 ( 2 ), 266-272 CODEN: SRIMDO ; ISSN: 1553-3174 . ( Taylor & Francis, Inc. ) The synthesis of amino-acid-capped gold nanoparticles (GNPs) and their characterization using agarose gel electrophoresis are reported. The GNPs were capped with L-Arginine and L-Glutamic acids at different pH. At the physiol. pH, the results obtained revealed that the interactions between L-Arginine, L-Glutamic acid, and GNPs were of the electrostatic and covalent/ coordinate types, resp. The capped GNPs possessing free amine/carboxylic groups could play an important role in conjugating biomols. (e.g., proteins) in various nanobiotechnol. applications. In addn., if the pH of the target environment is const., capped GNPs bound electrostatically are preferred and when variable, then amino-acid-capped GNPs bound covalently/ coordinately are recommended. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xkslaqu7s%253D&md5=95d6b592f5012385764a51b78f212a8d
- 20 Selvakannan, P. R. ; Mandal, S. ; Phadtare, S. ; Gole, A. ; Pasricha, R. ; Adyanthaya, S. D. ; Sastry, M. Water-Dispersible Tryptophan-Protected Gold Nanoparticles Prepared by the Spontaneous Reduction of Aqueous Chloroaurate Ions by the Amino Acid . J. Colloid Interface Sci. 2004 , 269 , 97 – 102 , DOI: 10.1016/S0021-9797(03)00616-7 Google Scholar 20 Water-dispersible tryptophan-protected gold nanoparticles prepared by the spontaneous reduction of aqueous chloroaurate ions by the amino acid Selvakannan, P. R.; Mandal, Saikat; Phadtare, Sumant; Gole, Anand; Pasricha, Renu; Adyanthaya, S. D.; Sastry, Murali Journal of Colloid and Interface Science ( 2004 ), 269 ( 1 ), 97-102 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Science ) The synthesis of water-dispersible amino-acid-protected gold nanoparticles by the spontaneous redn. of aq. chloroaurate ions by tryptophan is described. Water-dispersible gold nanoparticles may also be obtained by the sequential synthesis of the gold nanoparticles by borohydride redn. of chloroauric acid followed by capping with tryptophan. Comparison of the proton NMR spectroscopic signatures from the tryptophan-protected gold nanoparticles obtained by the two processes indicated that the indole group in tryptophan is responsible for redn. of the aq. chloroaurate ions. The redn. of the metal ions is accompanied by oxidative polymn. of the indole group of the tryptophan mols. and, consequently, some degree of crosslinking of the gold nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXptlCgt74%253D&md5=fae229bad885f957fc499e5367ccb6fc
- 21 Selvakannan, P. R. ; Mandal, S. ; Phadtare, S. ; Pasricha, R. ; Sastry, M. Capping of Gold Nanoparticles by the Amino Acid Lysine Renders Them Water-Dispersible . Langmuir 2003 , 19 , 3545 – 3549 , DOI: 10.1021/la026906v Google Scholar 21 Capping of Gold Nanoparticles by the Amino Acid Lysine Renders Them Water-Dispersible Selvakannan, P. R.; Mandal, Saikat; Phadtare, Sumant; Pasricha, Renu; Sastry, Murali Langmuir ( 2003 ), 19 ( 8 ), 3545-3549 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Capping aq. gold nanoparticles with the amino acid lysine stabilizes the particles in soln. electrostatically and also renders them water-dispersible. The lysine-capped gold nanoparticles may be obtained in the form of a dry powder after evapn. of the aq. component, this powder being extremely stable in air and readily redispersible in water. Development of protocols for the synthesis of water-dispersible nanoparticles has immense application in a variety of fields, but clearly more so in biorelated areas such as biolabeling and biosensing. The amino acid protected gold nanoparticles have been characterized by UV-vis spectroscopy, TEM, thermogravimetric anal. (TGA), and proton NMR spectroscopy. To the best of the authors' knowledge, this is the first report on use of an amino acid for stabilizing and rendering gold nanoparticles water-dispersible. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhslSlt7k%253D&md5=5c2a9c49e39cb7e73e0de4b4ae98778a
- 22 Wangoo, N. ; Bhasin, K. K. ; Mehta, S. K. ; Suri, C. R. Synthesis and Capping of Water-Dispersed Gold Nanoparticles by an Amino Acid: Bioconjugation and Binding Studies . J. Colloid Interface Sci. 2008 , 323 , 247 – 254 , DOI: 10.1016/j.jcis.2008.04.043 Google Scholar 22 Synthesis and capping of water-dispersed gold nanoparticles by an amino acid: Bioconjugation and binding studies Wangoo, Nishima; Bhasin, K. K.; Mehta, S. K.; Suri, C. Raman Journal of Colloid and Interface Science ( 2008 ), 323 ( 2 ), 247-254 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Inc. ) The authors report a novel strategy for the synthesis of aq. stable, carboxylated Au nanoparticles (GNPs) by using glutamic acid as the reducing agent. The ratio of chloroaurate ions, AuCl- 4 to glutamic acid was optimized in the reaction medium to obtain monodispersed GNPs. Glutamic acid reduced Au nanoparticles were characterized by UV-visible, FTIR, dynamic light scattering and TEM, which demonstrated high stability in aq. soln. over a period of time indicating stabilization via surface-bound amino acid. Functionalized nanoparticles were conjugated with protein mols. through electrostatic attraction between the surface-terminated neg. charged carboxylate groups (-COO-) of glutamic acid and the pos. charged amino groups (-NH+3) of the protein. The conjugation efficiency of the GNP:protein conjugates was confirmed qual. and quant. through gel electrophoresis and crit. flocculation concn. anal. The interaction between functionalized GNPs with protein mols. was studied using fluorescence spectroscopy showing the fluorescence quenching of the tryptophan residues of protein mols. after conjugation. CD studies of the conjugates confirmed that the protein undergoes a more flexible conformational state on the boundary surface of GNPs after conjugation. There was substantial conformational transition from α-helix to β-sheet structure after conjugation of protein to GNPs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmvVemu7w%253D&md5=382cd2df4457414516d1214237fce899
- 23 Malik, P. ; Shankar, R. ; Malik, V. ; Sharma, N. ; Mukherjee, T. K. Green Chemistry Based Benign Routes for Nanoparticle Synthesis . J. Nanopart. 2014 , 2014 , 1 – 14 , DOI: 10.1155/2014/302429 Google Scholar There is no corresponding record for this reference.
- 24 Zaheer, Z. ; Malik, M. A. ; Al-Nowaiser, F. M. ; Khan, Z. Preparation of Silver Nanoparticles Using Tryptophan and Its Formation Mechanism . Colloids Surf., B 2010 , 81 , 587 – 592 , DOI: 10.1016/j.colsurfb.2010.08.001 Google Scholar 24 Preparation of silver nanoparticles using tryptophan and its formation mechanism Zaheer, Zoya; Malik, Maqsood Ahmad; Al-Nowaiser, F. M.; Khan, Zaheer Colloids and Surfaces, B: Biointerfaces ( 2010 ), 81 ( 2 ), 587-592 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) A non-toxic route was used for the prepn. of silver nanoparticles using tryptophan (Trp) as reducing/stabilizing agent in the presence of cetyltrimethyl ammonium bromide (CTAB). Role of water sol. neutral polymer poly(vinylpyrrolidone) (PVP) was studied on the growth of yellow color silver nanoparticle formation. The synthesized nanostructures were characterized by UV-Visible absorption spectroscopy, transmission electron microscopy (TEM) by observing the size and distribution of silver nanoparticles. As the reaction proceeded, particles grew up to about 10 and 20 nm in the presence and absence of PVP, resp., as detd. by TEM. The formed nanoparticles showed the highest absorption plasmon band at 425 nm. Rate of silver sol formation increases with the [Trp], [CTAB] and [PVP], reaching a limiting value and then decreases with the increase in concns. of these reagents. It was obsd. that nanoparticles are spherical, aggregated and polydispersed in the absence and presence of PVP, resp. On the basis of kinetic data, a suitable mechanism is proposed and discussed for the silver sol formation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFynsb7I&md5=eba869ddf2647f64267829fcfce27759
- 25 Chandra, A. ; Singh, M. Amino Acid-Functionalized Silver Nanoparticles as Green Catalyst for Methylene Blue Reduction . International Scholarly and Scientific Research & Innovation 2015 , 9 , 1211 – 1217 , DOI: 10.5281/zenodo.1110580 Google Scholar There is no corresponding record for this reference.
- 26 Roy, M. ; Mukherjee, P. ; Mandal, B. P. ; Sharma, R. K. ; Tyagi, A. K. ; Kale, S. P. Biomimetic Synthesis of Nanocrystalline Silver Sol Using Cysteine: Stability Aspects and Antibacterial Activities . RSC Adv. 2012 , 2 , 6496 – 6503 , DOI: 10.1039/c2ra00785a Google Scholar 26 Biomimetic synthesis of nanocrystalline silver sol using cysteine: stability aspects and antibacterial activities Roy, Mainak; Mukherjee, Poulomi; Mandal, Balaji P.; Sharma, Rajendra K.; Tyagi, Avesh K.; Kale, Sharad P. RSC Advances ( 2012 ), 2 ( 16 ), 6496-6503 CODEN: RSCACL ; ISSN: 2046-2069 . ( Royal Society of Chemistry ) The study reports the development of a simple, environmentally benign green chem. route to produce stable silver nanoparticle (Ag-np) sols with excellent antibacterial properties under ambient conditions. The method involves the room temp. redn. of AgNO3 by cysteine (aq) and requires no addnl. capping/stabilizing agent. It essentially mimics the redox reaction that takes place during incubation of the cell-free ext. from Trichoderma asperellum in the presence of AgNO3 (aq) (P. Mukherjee, M. Roy, B. P. Mandal, G. K. Dey, P. K. Mukherjee, J. Ghatak, A. K. Tyagi and S. P. Kale, Nanotechnol., 2008, 19, 075103), wherein cysteine, a biomol. present in the fungal ext., acts as a potential reducing agent. Addnl., cysteine acts as a capping mol. in the present case. Formation of Ag-nps was evidenced from UV-Vis, TEM, XRD and EDS studies. The stability of Ag sols was shown to depend strongly on the concn. of cysteine relative to that of AgNO3. Sols obtained by reacting 0.1 mM of cysteine with 1 mM of AgNO3 remained stable for more than one month at 24 °C. The role of cysteine as capping mol. and the possible modes of its linkages with Ag-nps was studied by FT-IR, XPS and Raman spectroscopy. Bonding of Ag with either or all the 3, thiolate, amino and carboxylate groups of the cysteine mol. via stable PH configuration is believed to have resulted in the stabilization of the Ag-nps. Antibacterial activity of the cysteine capped Ag sol was studied along with that of the Ag sol obtained by fungal route. Both the sols exhibited excellent and comparable efficacies as bactericidal agents against gram neg. bacteria E. coli BW (25113), with one of the lowest min. inhibitory concn. (MIC) and min. bactericidal concn. (MBC) values published so far. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtVeisLrM&md5=c9fbf7c3402404061b659a4534e0bf45
- 27 Csapó, E. ; Patakfalvi, R. ; Hornok, V. ; Tóth, L. T. ; Sipos, Á. ; Szalai, A. ; Csete, M. ; Dékány, I. Effect of PH on Stability and Plasmonic Properties of Cysteine-Functionalized Silver Nanoparticle Dispersion . Colloids Surf., B 2012 , 98 , 43 – 49 , DOI: 10.1016/j.colsurfb.2012.03.036 Google Scholar 27 Effect of pH on stability and plasmonic properties of cysteine-functionalized silver nanoparticle dispersion Csapo, Edit; Patakfalvi, Rita; Hornok, Viktoria; Toth, Laszlo Tamas; Sipos, Aron; Szalai, Aniko; Csete, Maria; Dekany, Imre Colloids and Surfaces, B: Biointerfaces ( 2012 ), 98 ( ), 43-49 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) Citrate-stabilized spherical silver nanoparticles (Ag NPs) with d = 8.25 ± 1.25 nm diam. were prepd. and functionalized with L-cysteine (Cys) in aq. dispersion. The nanosilver-cysteine interactions have been studied by Raman and 1H NMR spectroscopy. The effect of pH on stability of biofunctionalized Ag NPs was studied. The cysteine-capped nanosilver dispersions remain stable at higher pH (pH > 7), while the degree of aggregation increased as the pH decreased. Below pH ∼7, the characteristic surface plasmon band of bare silver nanoparticles was back-shifted from λmeasuredbareAgNP = 391nm to λmeasured1 = 387-391nm, while the presence of a new band at λmeasured2 = 550-600nm was also obsd. depending on pH. Finite element method (FEM) was applied to numerically compute the absorption spectra of aq. dispersions contg. bare and cysteine-functionalized Ag NPs at different pH. Both the dynamic light scattering (DLS) measurements, Zeta potential values and the transmission electron microscopic (TEM) images confirmed the authors' supposition. Namely, electrostatic interaction arose between the deprotonated carboxylate (COO-) and protonated amino groups (NH3 +) of the amino acid resulting in crosslinking network of the Ag NPs between pH ∼3 and 7. If the pH is measurable .ltorsim.3, parallel with the protonation of citrate and L-cysteine mols. the connection of the particles via L-cysteine is partly decompd. resulting in decrease of second plasmon band intensity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XpsVKqsbc%253D&md5=f339cd063f59885d4e0779f08d498d75
- 28 Selvakannan, P. R. ; Swami, A. ; Srisathiyanarayanan, D. ; Shirude, P. S. ; Pasricha, R. ; Mandale, A. B. ; Sastry, M. Synthesis of aqueous Au core– Ag shell nanoparticles using tyrosine as a pH-dependent reducing agent and assembling phase-transferred silver nanoparticles at the air- water interface . Langmuir 2004 , 20 , 7825 – 7836 , DOI: 10.1021/la049258j Google Scholar 28 Synthesis of Aqueous Au Core-Ag Shell Nanoparticles Using Tyrosine as a pH-Dependent Reducing Agent and Assembling Phase-Transferred Silver Nanoparticles at the Air-Water Interface Selvakannan, PR.; Swami, Anita; Srisathiyanarayanan, D.; Shirude, Pravin S.; Pasricha, Renu; Mandale, Anandrao B.; Sastry, Murali Langmuir ( 2004 ), 20 ( 18 ), 7825-7836 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) We demonstrate that the amino acid tyrosine is an excellent reducing agent under alk. conditions and may be used to reduce Ag+ ions to synthesize stable silver nanoparticles in water. The tyrosine-reduced silver nanoparticles may be sepd. out as a powder that is readily redispersible in water. The silver ion redn. at high pH occurs due to ionization of the phenolic group in tyrosine that is then capable of reducing Ag+ ions and is in turn converted to a semi-quinone structure. These silver nanoparticles can easily be transferred to chloroform contg. the cationic surfactant octadecylamine by an electrostatic complexation process. The now hydrophobic silver nanoparticles may be spread on the surface of water and assembled into highly ordered, linear superstructures that could be transferred as multilayers onto suitable supports by the versatile Langmuir-Blodgett technique. Further, tyrosine mols. bound to the surface of Au nanoparticles through amine groups in the amino acid may be used to selectively reduce silver ions at high pH on the surface of the Au nanoparticles, thus leading to a simple strategy for realizing phase-pure Au core-Ag shell nanostructures. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXls1Kkt74%253D&md5=ec3102944fcb4dc19693afd5f1c26574
- 29 Iravani, S. Green Synthesis of Metal Nanoparticles Using Plants . Green Chem. 2011 , 13 , 2638 – 2650 , DOI: 10.1039/c1gc15386b Google Scholar 29 Green synthesis of metal nanoparticles using plants Iravani, Siavash Green Chemistry ( 2011 ), 13 ( 10 ), 2638-2650 CODEN: GRCHFJ ; ISSN: 1463-9262 . ( Royal Society of Chemistry ) A review. In recent years, the development of efficient green chem. methods for synthesis of metal nanoparticles has become a major focus of researchers. They have investigated in order to find an eco-friendly technique for prodn. of well-characterized nanoparticles. One of the most considered methods is prodn. of metal nanoparticles using organisms. Among these organisms plants seem to be the best candidates and they are suitable for large-scale biosynthesis of nanoparticles. Nanoparticles produced by plants are more stable and the rate of synthesis is faster than in the case of microorganisms. Moreover, the nanoparticles are more various in shape and size in comparison with those produced by other organisms. The advantages of using plant and plant-derived materials for biosynthesis of metal nanoparticles have interested researchers to investigate mechanisms of metal ions uptake and bioredn. by plants, and to understand the possible mechanism of metal nanoparticle formation in plants. In this review, most of the plants used in metal nanoparticle synthesis are shown. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVSksb3N&md5=d8fe8cd73ddbf03826145cc6c075b6c9
- 30 Natsuki, J. ; Natsuki, T. ; Hashimoto, Y. A Review of Silver Nanoparticles: Synthesis Methods, Properties and Applications . Int. J. Mater. Sci. Appl. 2015 , 4 , 325 – 332 , DOI: 10.11648/j.ijmsa.20150405.17 Google Scholar 30 A review of silver nanoparticles: synthesis methods, properties and applications Natsuki, Jun; Natsuki, Toshiaki; Hashimoto, Yoshio International Journal of Materials Science and Applications ( 2015 ), 4 ( 5 ), 325-332 CODEN: IJMSM7 ; ISSN: 2327-2643 . ( Science Publishing Group ) In recent years, nanoparticles of noble metals such as gold, silver and palladium have drawn immense attention due to the wide range of new applications in various fields of industry. Particularly, silver nanoparticles have significant interest in medical applications such as very effective antibacterial agents without the toxic effects, and industry application such as inkjet inks contg. well uniform dispersions of nano-sized silver particles that are useful for producing electronic circuits. It is important that the silver nanoparticles require not only the particles to be of nano-size, but also synthesis of the nanoparticles to be produced easily and at low cost. Over the past few decades, many synthetic methods of silver nanoparticles have been studied. This paper aims to review different synthesis routes of silver nanoparticles and their applications. In particular, we mainly present several chem. approaches to prepg. silver nanoparticles and their properties as well as applications based on our recent studies. The focus is on effective and efficient synthesis of pure colloidal silver nanoparticles with high elec. cond. and their potential application. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXlsFyhsLs%253D&md5=81c282bc341cb10cf918df1193cf39c3
- 31 Rauwel, P. ; Küünal, S. ; Ferdov, S. ; Rauwel, E. A review on the green synthesis of silver nanoparticles and their morphologies studied via TEM . Adv. Mater. Sci. Eng. 2015 , 2015 , 1 – 9 , DOI: 10.1155/2015/682749 Google Scholar There is no corresponding record for this reference.
- 32 Siddiqi, K. S. ; Husen, A. ; Rao, R. A. A Review on Biosynthesis of Silver Nanoparticles and Their Biocidal Properties . J. Nanobiotechnol. 2018 , 16 , 1 – 28 , DOI: 10.1186/s12951-018-0334-5 Google Scholar There is no corresponding record for this reference.
- 33 Marambio-Jones, C. ; Hoek, E. M. V. A Review of the Antibacterial Effects of Silver Nanomaterials and Potential Implications for Human Health and the Environment . J. Nanopart. Res. 2010 , 12 , 1531 – 1551 , DOI: 10.1007/s11051-010-9900-y Google Scholar 33 A review of the antibacterial effects of silver nanomaterials and potential implications for human health and the environment Marambio-Jones, Catalina; Hoek, Eric M. V. Journal of Nanoparticle Research ( 2010 ), 12 ( 5 ), 1531-1551 CODEN: JNARFA ; ISSN: 1388-0764 . ( Springer ) Here, we present a review of the antibacterial effects of silver nanomaterials, including proposed antibacterial mechanisms and possible toxicity to higher organisms. For purpose of this review, silver nanomaterials include silver nanoparticles, stabilized silver salts, silver-dendrimer, polymer and metal oxide composites, and silver-impregnated zeolite and activated carbon materials. While there is some evidence that silver nanoparticles can directly damage bacteria cell membranes, silver nanomaterials appear to exert bacteriocidal activity predominantly through release of silver ions followed (individually or in combination) by increased membrane permeability, loss of the proton motive force, inducing de-energization of the cells and efflux of phosphate, leakage of cellular content, and disruption DNA replication. Eukaryotic cells could be similarly impacted by most of these mechanisms and, indeed, a small but growing body of literature supports this concern. Most antimicrobial studies are performed in simple aquatic media or cell culture media without proper characterization of silver nanomaterial stability (aggregation, dissoln., and re-pptn.). Silver nanoparticle stability is governed by particle size, shape, and capping agents as well as soln. pH, ionic strength, specific ions and ligands, and org. macromols.-all of which influence silver nanoparticle stability and bioavailability. Although none of the studies reviewed definitively proved any immediate impacts to human health or the environment by a silver nanomaterial contg. product, the entirety of the science reviewed suggests some caution and further research are warranted given the already widespread and rapidly growing use of silver nanomaterials. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsFOrur0%253D&md5=6aae4aee458d3e417b41f58f98080449
- 34 Kulkarni, S. K. Nanotechnology: Principles and Practices ; Springer International Publishing , 2015 . Google Scholar There is no corresponding record for this reference.
- 35 Tran, Q. H. ; Nguyen, V. Q. ; Le, A.-T. Silver Nanoparticles: Synthesis, Properties, Toxicology, Applications and Perspectives . Advances in Natural Sciences: Nanoscience and Nanotechnology 2013 , 4 , 033001 , DOI: 10.1088/2043-6262/4/3/033001 Google Scholar 35 Silver nanoparticles: synthesis, properties, toxicology, applications and perspective Tran, Quang Huy; Nguyen, Van Quy; Le, Anh-Tuan Advances in Natural Sciences: Nanoscience and Nanotechnology ( 2013 ), 4 ( 3 ), 033001 CODEN: ANSNCK ; ISSN: 2043-6262 . ( IOP Publishing Ltd. ) A review. In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H5N1), diarrhea (Escherichia coli), cholera (-Vibrio cholera), etc throughout the world. The comprehensive treatments of environments contg. infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicol. considerations of Ag-NPs to humans and ecol. are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCjsbw%253D&md5=13357b298b4cb04ededfdc2083fca9d0
- 36 Argueta Figueroa, L. ; Arenas-Arrocena ; Ma, C. ; Díaz-Herrera, A. P. ; García-Benítez, S. V. ; García-Contreras, R. Propiedades Antimicrobianas y Citotóxicas de Un Adhesivo de Uso Ortodóncico Adicionado Con Nanopartículas de Plata . Mundo Nano. Revista Interdisciplinaria en Nanociencias y Nanotecnología 2018 , 12 , 1 , DOI: 10.22201/ceiich.24485691e.2019.22.62550 Google Scholar There is no corresponding record for this reference.
- 37 Xing, M. ; Ge, L. ; Wang, M. ; Li, Q. ; Li, X. ; Ouyang, J. Nanosilver Particles in Medical Applications: Synthesis, Performance, and Toxicity . Int. J. Nanomed. 2014 , 9 , 2399 – 2407 , DOI: 10.2147/IJN.S55015 Google Scholar There is no corresponding record for this reference.
- 38 Cheng, G. ; Dai, M. ; Ahmed, S. ; Hao, H. ; Wang, X. ; Yuan, Z. Antimicrobial Drugs in Fighting against Antimicrobial Resistance . Frontiers in Microbiology 2016 , DOI: 10.3389/fmicb.2016.00470 Google Scholar There is no corresponding record for this reference.
- 39 Raveendran, P. ; Fu, J. ; Wallen, S. L. Completely “Green” Synthesis and Stabilization of Metal Nanoparticles . J. Am. Chem. Soc. 2003 , 125 , 13940 – 13941 , DOI: 10.1021/ja029267j Google Scholar 39 Completely green synthesis and stabilization of metal nanoparticles Raveendran, Poovathinthodiyil; Fu, Jie; Wallen, Scott L. Journal of the American Chemical Society ( 2003 ), 125 ( 46 ), 13940-13941 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A completely green synthetic method for producing silver nanoparticles is introduced. The process is simple, environmentally benign and quite efficient. By gentle heating of an aq. starch soln. contg. silver nitrate and glucose, relatively monodisperse, starched silver nanoparticles are produced. β-D-Glucose serves as the green reducing agent, while starch serves as the stabilization agent. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXot12ms7k%253D&md5=924330e7ba08a32194f54a1875c25898
- 40 Mann, S. Biomineralization and biomimetic materials chemistry. Biomimetic materials chemistry ; Mann, S. , Ed.; VCH Publishers, Inc. : New York, USA , 1996 , 47 . Google Scholar There is no corresponding record for this reference.
- 41 Zhang, X. F. ; Liu, Z. G. ; Shen, W. ; Gurunathan, S. Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches . Int. J. Mol. Sci. 2016 , 17 , 1534 , DOI: 10.3390/ijms17091534 Google Scholar 41 Silver nanoparticles: synthesis, characterization, properties, applications, and therapeutic approaches Zhang, Xi-Feng; Liu, Zhi-Guo; Shen, Wei; Gurunathan, Sangiliyandi International Journal of Molecular Sciences ( 2016 ), 17 ( 9 ), 1534/1-1534/34 CODEN: IJMCFK ; ISSN: 1422-0067 . ( MDPI AG ) Recent advances in nanoscience and nanotechnol. radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in biomedical applications. AgNPs play an important role in nanoscience and nanotechnol., particularly in nanomedicine. Although several noble metals have been used for various purposes, AgNPs have been focused on potential applications in cancer diagnosis and therapy. In this review, we discuss the synthesis of AgNPs using phys., chem., and biol. methods. We also discuss the properties of AgNPs and methods for their characterization. More importantly, we extensively discuss the multifunctional bio-applications of AgNPs; for example, as antibacterial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anti-cancer agents, and the mechanism of the anti-cancer activity of AgNPs. In addn., we discuss therapeutic approaches and challenges for cancer therapy using AgNPs. Finally, we conclude by discussing the future perspective of AgNPs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvF2qs7rM&md5=e40f79b90c36beb092c677d11d137fdd
- 42 Arokiyaraj, S. ; Arasu, M. V. ; Vincent, S. ; Prakash, N. U. ; Choi, S. H. ; Oh, Y. K. ; Choi, K. C. ; Kim, K. H. Rapid Green Synthesis of Silver Nanoparticles from Chrysanthemum Indicum Land Its Antibacterial and Cytotoxic Effects: An in Vitro Study . Int. J. Nanomed. 2014 , 9 , 379 – 388 , DOI: 10.2147/IJN.S53546 Google Scholar There is no corresponding record for this reference.
- 43 Maruyama, T. ; Fujimoto, Y. ; Maekawa, T. Synthesis of Gold Nanoparticles Using Various Amino Acids . J. Colloid Interface Sci. 2015 , 447 , 254 – 257 , DOI: 10.1016/j.jcis.2014.12.046 Google Scholar 43 Synthesis of gold nanoparticles using various amino acids Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya Journal of Colloid and Interface Science ( 2015 ), 447 ( ), 254-257 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier B.V. ) Gold nanoparticles (4-7 nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl-4 soln. with an amino acid at 80°C for 20 min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solns. varied with the amino acids used for the redn. L-Histidine was used as a reducing agent, and the effects of the synthesis conditions on the gold nanoparticles were investigated. The His and AuCl-4 concns. affected the size of the gold nanoparticles and their aggregates. The pH of the reaction soln. also affected the reaction yields and the shape of the gold nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVKgtQ%253D%253D&md5=abc8ab54b03371d9f2bcb4e4228ebc69
- 44 Mu, X. ; Qi, L. ; Qiao, J. ; Ma, H. One-Pot Synthesis of Tyrosine-Stabilized Fluorescent Gold Nanoclusters and Their Application as Turn-on Sensors for Al3+ Ions and Turn-off Sensors for Fe3+ Ions . Anal. Methods 2014 , 6 , 6445 – 6451 , DOI: 10.1039/C4AY01137F Google Scholar 44 One-pot synthesis of tyrosine-stabilized fluorescent gold nanoclusters and their application as turn-on sensors for Al3+ ions and turn-off sensors for Fe3+ ions Mu, Xiaoyu; Qi, Li; Qiao, Juan; Ma, Huimin Analytical Methods ( 2014 ), 6 ( 16 ), 6445-6451 CODEN: AMNEGX ; ISSN: 1759-9679 . ( Royal Society of Chemistry ) The simplicity of the one-pot green synthesis routine and the capability of surface modification of various bioactive mols. make gold nanoclusters (Au NCs) highly suitable as scaffolds for the construction of novel chem. and biol. sensors. In this work, we report a novel strategy to prep. amino acid stabilized fluorescent Au NCs via a green one-pot process. The obtained Au NCs possessed light green fluorescence with max. emission at 498 nm and their quantum yield (QY) was evaluated to be 1.68%. Subsequently, the developed fluorescent Au NC biosensor allowed sensitive and selective detection of Fe3+ ions based on fluorescence quenching with a detection limit of 0.2 μM and Al3+ ions based on enhanced fluorescence with a detection limit of 0.3 μM, resp. Furthermore, we testified the feasibility of applying this fluorescent probe for real sample anal. through the detection of Al3+ ions and Fe3+ ions in lake water, pond water and tap water. These results indicated that the as-prepd. Au NCs had great potential to be developed as the favorable sensor for detection of metal ions in real samples. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFWitrzP&md5=4ebf006d4e70bf5dda41182fac6399ae
- 45 Dubey, K. ; Anand, B. G. ; Badhwar, R. ; Bagler, G. ; Navya, P. N. ; Daima, H. K. ; Kar, K. Tyrosine- and Tryptophan-Coated Gold Nanoparticles Inhibit Amyloid Aggregation of Insulin . Amino Acids 2015 , 47 , 2551 – 2560 , DOI: 10.1007/s00726-015-2046-6 Google Scholar 45 Tyrosine- and tryptophan-coated gold nanoparticles inhibit amyloid aggregation of insulin Dubey, Kriti; Anand, Bibin G.; Badhwar, Rahul; Bagler, Ganesh; Navya, P. N.; Daima, Hemant Kumar; Kar, Karunakar Amino Acids ( 2015 ), 47 ( 12 ), 2551-2560 CODEN: AACIE6 ; ISSN: 0939-4451 . ( Springer-Verlag GmbH ) Here, we have strategically synthesized stable gold (AuNPsTyr, AuNPsTrp) and silver (AgNPsTyr) nanoparticles which are surface functionalized with either tyrosine or tryptophan residues and have examd. their potential to inhibit amyloid aggregation of insulin. Inhibition of both spontaneous and seed-induced aggregation of insulin was obsd. in the presence of AuNPsTyr, AgNPsTyr, and AuNPsTrp nanoparticles. These nanoparticles also triggered the disassembly of insulin amyloid fibrils. Surface functionalization of amino acids appears to be important for the inhibition effect since isolated tryptophan and tyrosine mols. did not prevent insulin aggregation. Bioinformatics anal. predicts involvement of tyrosine in H-bonding interactions mediated by its C=O, -NH2, and arom. moiety. These results offer significant opportunities for developing nanoparticle-based therapeutics against diseases related to protein aggregation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht1SgtbfE&md5=05ac4ada9be9c9fa7694d60cdfa597c1
- 46 Joshi, H. ; Shirude, P. S. ; Bansal, V. ; Ganesh, K. N. ; Sastry, M. Isothermal Titration Calorimetry Studies on the Binding of Amino Acids to Gold Nanoparticles . J. Phys. Chem. B 2004 , 108 , 11535 – 11540 , DOI: 10.1021/jp048766z Google Scholar 46 Isothermal titration calorimetry studies on the binding of amino acids to gold nanoparticles Joshi, Hrushikesh; Shirude, Pravin S.; Bansal, Vipul; Ganesh, K. N.; Sastry, Murali Journal of Physical Chemistry B ( 2004 ), 108 ( 31 ), 11535-11540 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Isothermal titrn. calorimetry (ITC) is a powerful and highly sensitive technique commonly used to study interactions between biomols. in dil. aq. solns., both from thermodn. and kinetics points of view. In this report, we show that ITC may be used to follow the binding of ligands such as amino acids to the surface of inorg. materials such as gold nanoparticles. More specifically, we have studied the binding of one basic amino acid, lysine, and an acidic amino acid, aspartic acid, with aq. gold nanoparticles at physiol. pH. Strong binding of aspartic acid with the gold nanoparticles under these conditions is indicated by ITC, while weak binding was obsd. in the case of lysine. The differences in binding are attributed to protonation of amine groups in lysine at physiol. pH (pI ∼ 9.4) while they are not protonated for aspartic acid (pI ∼ 2.77). That this is the likely mechanism is indicated by the ITC measurement of binding of lysine with nanogold at pH 11 (when the amine groups are not protonated). The binding of the amino acids with gold nanoparticles has been validated with other techniques such as gel electrophoresis and x-ray photoemission spectroscopy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXltl2lsbk%253D&md5=d59c01679f49473373fb26999cd2fb63
- 47 Wang, X. ; Li, Y. Synthesis and Characterization of Lanthanide Hydroxide Single-Crystal Nanowires . Angew. Chem. 2002 , 114 , 4984 – 4987 , DOI: 10.1002/ange.200290048 Google Scholar There is no corresponding record for this reference.
- 48 Mai, H. X. ; Sun, L. D. ; Zhang, Y. W. ; Si, R. ; Feng, W. ; Zhang, H. P. ; Liu, H. C. ; Yan, C. H. Shape-Selective Synthesis and Oxygen Storage Behavior of Ceria Nanopolyhedra, Nanorods, and Nanocubes . J. Phys. Chem. B 2005 , 109 , 24380 – 24385 , DOI: 10.1021/jp055584b Google Scholar 48 Shape-Selective Synthesis and Oxygen Storage Behavior of Ceria Nanopolyhedra, Nanorods, and Nanocubes Mai, Hao-Xin; Sun, Ling-Dong; Zhang, Ya-Wen; Si, Rui; Feng, Wei; Zhang, Hong-Peng; Liu, Hai-Chao; Yan, Chun-Hua Journal of Physical Chemistry B ( 2005 ), 109 ( 51 ), 24380-24385 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Single-cryst. and uniform nanopolyhedra, nanorods, and nanocubes of cubic CeO2 were selectively prepd. by a hydrothermal method at temps. in the range of 100-180 °C under different NaOH concns., using Ce(NO3)3 as the cerium source. According to high-resoln. transmission electron microscopy, they have different exposed crystal planes: {111} and {100} for polyhedra, {110} and {100} for rods, and {100} for cubes. During the synthesis, the formation of hexagonal Ce(OH)3 intermediate species and their transformation into CeO2 at elevated temp., together with the base concn., have been demonstrated as the key factors responsible for the shape evolution. Oxygen storage capacity (OSC) measurements at 400 °C revealed that the oxygen storage takes place both at the surface and in the bulk for the as-obtained CeO2 nanorods and nanocubes, but is restricted at the surface for the nanopolyhedra just like the bulk one, because the {100}/{110}-dominated surface structures are more reactive for CO oxidn. than the {111}-dominated one. This result suggests that high OSC materials might be designed and obtained by shape-selective synthetic strategy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1Omtr3E&md5=e813a9265ad2ef9f6cde8471dad765b1
- 49 Kaneko, K. ; Inoke, K. ; Freitag, B. ; Hungria, A. B. ; Midgley, P. A. ; Hansen, T. W. ; Zhang, J. ; Ohara, S. ; Adschiri, T. Structural and Morphological Characterization of Cerium Oxide Nanocrystals Prepared by Hydrothermal Synthesis . Nano Lett. 2007 , 7 ( 2 ), 421 – 425 , DOI: 10.1021/nl062677b Google Scholar 49 Structural and Morphological Characterization of Cerium Oxide Nanocrystals Prepared by Hydrothermal Synthesis Kaneko, Kenji; Inoke, Koji; Freitag, Bert; Hungria, Ana B.; Midgley, Paul A.; Hansen, Thomas W.; Zhang, Jing; Ohara, Satoshi; Adschiri, Tadafumi Nano Letters ( 2007 ), 7 ( 2 ), 421-425 CODEN: NALEFD ; ISSN: 1530-6984 . ( American Chemical Society ) Colloidal cerium oxide (CeO2) nanocrystals prepd. by hydrothermal synthesis were characterized by high-resoln. transmission electron microscopy (HRTEM) and three-dimensional electron tomog. (3D-ET). HRTEM images of individual CeO2 nanocrystals were then simulated by Blochwave and multislice simulations to det. the at. arrangement and terminating atoms. The edge length distributions were between 5.0 and 8.0 nm with an av. edge length of 6.7 nm. The HRTEM images showed that the CeO2 particles were slightly truncated revealing {220} facets. 3D-ET revealed that the CeO2 nanocrystals exposed predominantly {200} cubic facets. The nanocrystals were truncated at the corners exposing {111} octahedral facets and at the edges {220} dodecahedral facets. Furthermore, 3D-ET revealed the presence of some tetragonal-shaped CeO2 nanocrystals. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXktF2ktQ%253D%253D&md5=330852543d80c9633078c94966d87d5e
- 50 Yang, S. ; Gao, L. Controlled Synthesis and Self-Assembly of CeO 2 Nanocubes . J. Am. Chem. Soc. 2006 , 128 , 9330 – 9331 , DOI: 10.1021/ja063359h Google Scholar 50 Controlled Synthesis and Self-Assembly of CeO2 Nanocubes Yang, Songwang; Gao, Lian Journal of the American Chemical Society ( 2006 ), 128 ( 29 ), 9330-9331 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) CeO2 nanocubes (and nanorods) enclosed by six {200} planes with controlled sizes have been prepd. through a facile one-pot method. The nanocubes have a strong tendency to assemble into 2D and 3D arrays with regular patterns on a substrate, which is probably driven by the dipole-dipole interaction of polar {200} planes. The possible formation mechanism of the nanocubes has been put forward as the oriented aggregation mediated precursor growth. It is possible to use the synthesized nanocubes as building blocks to achieve {200}-perfect-oriented monolayers or thickness-controlled films and to apply the preparative method in the incorporation of heterogeneous atoms or nanoparticles for semiconductor doping or heterogeneous nanostructures. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmsVeks7o%253D&md5=696b56593c4b1e70f41f8366d5549611
- 51 Qian, L. ; Zhu, J. ; Du, W. ; Qian, X. Solvothermal Synthesis, Electrochemical and Photocatalytic Properties of Monodispersed CeO2 Nanocubes . Mater. Chem. Phys. 2009 , 115 , 835 – 840 , DOI: 10.1016/j.matchemphys.2009.02.047 Google Scholar 51 Solvothermal synthesis, electrochemical and photocatalytic properties of monodispersed CeO2 nanocubes Qian, Liwu; Zhu, Jun; Du, Weimin; Qian, Xuefeng Materials Chemistry and Physics ( 2009 ), 115 ( 2-3 ), 835-840 CODEN: MCHPDR ; ISSN: 0254-0584 . ( Elsevier B.V. ) Cubic-like CeO2 nanocrystals were prepd. through an improved-toluene solvothermal process using hexadecylamine (HAD) as a capping agent and CeCl3.7H2O as a precursor at 180° for 24 h. These nanocubes are ≈10 nm in size, and have a tendency to assemble into 2D superstructure. The obtained samples were characterized by x-ray powder diffraction (XRD) and TEM. The water content, the concn. of ligand, and kinds of aliph. amine played important roles in the formation of the novel morphol. A possible formation mechanism was proposed based on the controlling reaction parameters. The electrochem. and photocatalytic properties of the as-prepd. samples exhibited the size/shape-dependent properties and potential applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXltVynsrw%253D&md5=977753f15f7f4af99a6ba986c3c3f0da
- 52 Ke, J. ; Xiao, J. W. ; Zhu, W. ; Liu, H. ; Si, R. ; Zhang, Y. W. ; Yan, C. H. Dopant-Induced Modification of Active Site Structure and Surface Bonding Mode for High-Performance Nanocatalysts: CO Oxidation on Capping-Free (110)-Oriented CeO2:Ln (Ln = La-Lu) Nanowires . J. Am. Chem. Soc. 2013 , 135 , 15191 – 15200 , DOI: 10.1021/ja407616p Google Scholar 52 Dopant-Induced Modification of Active Site Structure and Surface Bonding Mode for High-Performance Nanocatalysts: CO Oxidation on Capping-free (110)-oriented CeO2:Ln (Ln = La-Lu) Nanowires Ke, Jun; Xiao, Jia-Wen; Zhu, Wei; Liu, Haichao; Si, Rui; Zhang, Ya-Wen; Yan, Chun-Hua Journal of the American Chemical Society ( 2013 ), 135 ( 40 ), 15191-15200 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) Active center engineering at at. level is a grand challenge for catalyst design and optimization in many industrial catalytic processes. Exploring new strategies to delicately tailor the structures of active centers and bonding modes of surface reactive intermediates for nanocatalysts is crucial to high-efficiency nanocatalysis that bridges heterogeneous and homogeneous catalysis. Here we demonstrate a robust approach to tune the CO oxidn. activity over CeO2 nanowires (NWs) through the modulation of the local structure and surface state around LnCe' defect centers by doping other lanthanides (Ln), based on the continuous variation of the ionic radius of lanthanide dopants caused by the lanthanide contraction. Homogeneously doped (110)-oriented CeO2:Ln NWs with no residual capping agents were synthesized by controlling the redox chem. of Ce-(III)/Ce-(IV) in a mild hydrothermal process. The CO oxidn. reactivity over CeO2:Ln NWs was dependent on the Ln dopants, and the reactivity reached the max. in turnover rates over Nd-doped samples. On the basis of the results obtained from combined experimentations and d. functional theory simulations, the decisive factors of the modulation effect along the lanthanide dopant series were deduced as surface oxygen release capability and the bonding configuration of the surface adsorbed species (i.e., carbonates and bicarbonates) formed during catalytic process, which resulted in the existence of an optimal doping effect from the lanthanide with moderate ionic radius. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVeksbbM&md5=eacb0b2d2f2ad2e595f2de20093b3461
- 53 Patil, S. ; Sandberg, A. ; Heckert, E. ; Self, W. ; Seal, S. Protein Adsorption and Cellular Uptake of Cerium Oxide Nanoparticles as a Function of Zeta Potential . Biomaterials 2007 , 28 , 4600 – 4607 , DOI: 10.1016/j.biomaterials.2007.07.029 Google Scholar 53 Protein adsorption and cellular uptake of cerium oxide nanoparticles as a function of zeta potential Patil, Swanand; Sandberg, Amanda; Heckert, Eric; Self, William; Seal, Sudipta Biomaterials ( 2007 ), 28 ( 31 ), 4600-4607 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) The surface chem. of biomaterials can have a significant impact on their performance in biol. applications. The recent work suggests that cerium oxide nanoparticles are potent antioxidants in cell culture models and the authors have evaluated several therapeutic applications of these nanoparticles in different biol. systems. Knowledge of protein adsorption and cellular uptake will be very useful in improving the beneficial effects of cerium oxide nanoparticles in biol. In the present study, the authors detd. the effect of zeta potential of cerium oxide nanoparticles on adsorption of bovine serum albumin (BSA) and cellular uptake in adenocarcinoma lung cells (A549). The zeta potential of the nanoparticles was varied by dispersing them in various acidic and basic pH solns. UV-visible spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS) were used for the protein adsorption and cellular uptake studies, resp. Nanoceria samples having pos. zeta potential were found to adsorb more BSA while the samples with neg. zeta potential showed little or no protein adsorption. The cellular uptake studies showed preferential uptake for the neg. charged nanoparticles. These results demonstrate that electrostatic interactions can play an important factor in protein adsorption and cellular uptake of nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXptFygurg%253D&md5=7b40e8f70d0d9f4c01624d21b7d321bd
- 54 Shah, M. ; Fawcett, D. ; Sharma, S. ; Tripathy, S. K. ; Poinern, G. E. J. Green Synthesis of Metallic Nanoparticles via Biological Entities . Materials 2015 , 8 , 7278 – 7308 , DOI: 10.3390/ma8115377 Google Scholar 54 Green synthesis of metallic nanoparticles via biological entities Shah, Monaliben; Fawcett, Derek; Sharma, Shashi; Tripathy, Suraj Kumar; Poinern, Gerrard Eddy Jai Materials ( 2015 ), 8 ( 11 ), 7278-7308 CODEN: MATEG9 ; ISSN: 1996-1944 . ( MDPI AG ) Nanotechnol. is the creation, manipulation and use of materials at the nanometer size scale (1 to 100 nm). At this size scale there are significant differences in many material properties that are normally not seen in the same materials at larger scales. Although nanoscale materials can be produced using a variety of traditional phys. and chem. processes, it is now possible to biol. synthesize materials via environment-friendly green chem. based techniques. In recent years, the convergence between nanotechnol. and biol. has created the new field of nanobiotechnol. that incorporates the use of biol. entities such as actinomycetes algae, bacteria, fungi, viruses, yeasts, and plants in a no. of biochem. and biophys. processes. The biol. synthesis via nanobiotechnol. processes have a significant potential to boost nanoparticles prodn. without the use of harsh, toxic, and expensive chems. commonly used in conventional phys. and chem. processes. The aim of this review is to provide an overview of recent trends in synthesizing nanoparticles via biol. entities and their potential applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXls12isrc%253D&md5=ad52fe8043087d1e502a7a799bb35168
- 55 Xu, S. ; Zhang, J. ; Paquet, C. ; Lin, Y. ; Kumacheva, E. From Hybrid Microgels to Photonic Crystals . Adv. Funct. Mater. 2003 , 13 , 468 – 472 , DOI: 10.1002/adfm.200304338 Google Scholar 55 From hybrid microgels to photonic crystals Xu, Shengqing; Zhang, Jiguang; Paquet, Chantal; Lin, Yuankun; Kumacheva, Eugenia Advanced Functional Materials ( 2003 ), 13 ( 6 ), 468-472 CODEN: AFMDC6 ; ISSN: 1616-301X . ( Wiley-VCH Verlag GmbH & Co. KGaA ) We have synthesized semiconductor and metal nanoparticles (NPs) in the constrained geometry of polymer microgels. We used electrostatically driven attraction between the ionic groups of the microgels and the precursor cations in the bulk liq. medium to introduce the cations in the interior of the microgel. In the second step, the cations in the microgel interior reacted with the anion (to obtain semiconductor NPs) or they were treated with a reducing agent (to obtain metal NPs). Good control over the size and the concn. of the NPs in the microgel particles was achieved by changing the compn. of the corresponding microgel. The doped microgel spheres were heated at pH 4 above the vol.-transition temp. of the polymer to expel the water from the microsphere interior; then the polymer was encapsulated with a hydrophobic polymeric shell. Hybrid core-shell particles were used as the building blocks of the nanostructured material with properties of a photonic crystal. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFeksrg%253D&md5=4935887e3a24f64f7d1508651f0e2adb
- 56 Epifani, M. ; Giannini, C. ; Tapfer, L. ; Vasanelli, L. Sol – Gel Synthesis and Characterization of Ag and Au Nanoparticles in SiO2, TiO2, and ZrO2 thin films . J. Am. Ceram. Soc. 2000 , 83 , 2385 – 2393 , DOI: 10.1111/j.1151-2916.2000.tb01566.x Google Scholar 56 Sol-gel synthesis and characterization of Ag and Au nanoparticles in SiO2, TiO2, and ZrO2 thin films Epifani, Mauro; Giannini, Cinzia; Tapfer, Leander; Vasanelli, Lorenzo Journal of the American Ceramic Society ( 2000 ), 83 ( 10 ), 2385-2393 CODEN: JACTAW ; ISSN: 0002-7820 . ( American Ceramic Society ) Silver and gold nanoparticles were synthesized by the sol-gel process in SiO2, TiO2, and ZrO2 thin films. A versatile method, based on the use of coordination chem., is presented for stabilizing Ag+ and Au3+ ions in sol-gel systems. Various ligands of the metal ions were tested, and for each system it was possible to find a suitable ligand capable of stabilizing the metal ions and preventing gold pptn. onto the film surface. Thin films were prepd. by spin-coating onto glass or fused silica substrates and then heat-treated at various temps. in air or H2 atmosphere for nucleating the metal nanoparticles. The Ag particle size was about 10 nm after heating the SiO2 film at 600°C and the TiO2 and ZrO2 films at 500°C. After heat treatment at 500°C, the Au particle size was 13 and 17 nm in the TiO2 and ZrO2 films, resp. The films were characterized by UV-vis optical absorption spectroscopy and X-ray diffraction, for studying the nucleation and the growth of the metal nanoparticles. The results are discussed with regard to the embedding matrix, the temp., and the atm. of the heat treatment, and it is concluded that crystn. of TiO2 and ZrO2 films may hinder the growth of Ag and Au particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXntlGrsLw%253D&md5=ec0dc5c3d8cd525b926e5f19e8304bb2
- 57 Gupta, N. ; Singh, H. P. ; Sharma, R. K. Single-Pot Synthesis: Plant Mediated Gold Nanoparticles Catalyzed Reduction of Methylene Blue in Presence of Stannous Chloride . Colloids Surf., A 2010 , 367 , 102 – 107 , DOI: 10.1016/j.colsurfa.2010.06.022 Google Scholar 57 Single-pot synthesis: Plant mediated gold nanoparticles catalyzed reduction of methylene blue in presence of stannous chloride Gupta, Nikesh; Singh, Henam Premananda; Sharma, Rakesh Kumar Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2010 ), 367 ( 1-3 ), 102-107 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Gold nanoparticles of about 20 nm in diam. and having λ max at 542 nm is prepd. by addn. of HAuCl4 soln. to green tea leaves ext. at room temp. The synthetic route does not involve any toxic chems. or org. solvent and it is totally aq. phase synthesis; so it is a green approach. The synthesized nanoparticles were used as a catalyst for the redn. of methylene blue dye in the presence of Sn(II) in aq. and micellar media and the rate of redn. is detd. by measuring the decrease in absorbance of the dye at 663 nm spectrophotometrically. The rate of redn. follows the order RateSDS > RateCTAB > Ratewater. The activation energy as detd. using Arrhenius equation for the reaction catalyzed by gold nanoparticles is 38.42 kJ mol-1 and the slow reaction rate of uncatalyzed reaction has been manifested through larger activation energy of about 88.13 kJ mol-1. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtVantLfE&md5=02e32bb6600ec53143643a01aaa3f31a
- 58 Niemeyer, C. M. Nanoparticles, Proteins, and Nucleic Acids: Biotechnology Meets Materials Science . Angew. Chem., Int. Ed. 2001 , 40 , 4128 – 4158 , DOI: 10.1002/1521-3773(20011119)40:22<4128::AID-ANIE4128>3.0.CO;2-S Google Scholar 58 Nanoparticles, proteins, and nucleic acids: biotechnology meets materials science Niemeyer, Christof M. Angewandte Chemie, International Edition ( 2001 ), 40 ( 22 ), 4128-4158 CODEN: ACIEF5 ; ISSN: 1433-7851 . ( Wiley-VCH Verlag GmbH ) A review. Based on fundamental chem., biotechnol. and materials science have developed over the past three decades into today's powerful disciplines which allow the engineering of advanced tech. devices and the industrial prodn. of active substances for pharmaceutical and biomedical applications. This review is focused on current approaches emerging at the intersection of materials research, nanosciences, and mol. biotechnol. This novel and highly interdisciplinary field of chem. is closely assocd. with both the phys. and chem. properties of org. and inorg. nanoparticles, as well as to the various aspects of mol. cloning, recombinant DNA and protein technol., and immunol. Evolutionary optimized biomols. such as nucleic acids, proteins, and supramol. complexes of these components, are utilized in the prodn. of nanostructured and mesoscopic architectures from org. and inorg. materials. The highly developed instruments and techniques of today's materials research are used for basic and applied studies of fundamental biol. processes. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFeisr0%253D&md5=e1198a7f5dce39d222fba59a6713c754
- 59 Shindel, M. M. ; Mohraz, A. ; Mumm, D. R. ; Wang, S. W. Modulating Colloidal Adsorption on a Two-Dimensional Protein Crystal . Langmuir 2009 , 25 , 1038 – 1046 , DOI: 10.1021/la802911p Google Scholar 59 Modulating Colloidal Adsorption on a Two-Dimensional Protein Crystal Shindel, Matthew M.; Mohraz, Ali; Mumm, Daniel R.; Wang, Szu-Wen Langmuir ( 2009 ), 25 ( 2 ), 1038-1046 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) The geometric and physicochem. properties of the protein streptavidin make it a useful building block in the construction and manipulation of nanoscale structures and devices. However, one requirement in exploiting streptavidin for "bottom-up" assembly is the capability to modulate protein-nanoparticle interactions. This work examines the effects of pH and the biotin-streptavidin interaction on the adsorption of colloidal gold onto a two-dimensional streptavidin crystal. Particle deposition was carried out below (pH 6), at (pH 7), and above (pH 8) the protein's isoelec. point with both biotinylated and nonbiotinylated nanoparticles. Particle surface coverage depends on deposition time and pH, and increases by 1.4-10 times when biotin is incorporated onto the particle surface. This coverage is highest for both particle types at pH 6 and decreases monotonically with increasing pH. Calcns. of interparticle potentials based on Derjaguin-Landau-Verwey-Overbeek (DLVO) theory demonstrate that this trend in surface coverage is most likely due to alterations in particle-surface electrostatic interactions and not a result of changes in interparticle electrostatic repulsion. Furthermore, post-adsorption alterations in pH demonstrate that electrostatically adsorbed particles can be selectively desorbed from the surface. Evaluation of the nonspecifically adsorbed fraction of biotinylated particles indicates that the receptor-ligand adsorption mechanism gives a higher rate of attachment to the substrate than nonspecific, electrostatic adsorption. This results in faster adsorption kinetics and higher coverages for biotinylated particles relative to the nonbiotinylated case. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFals7vO&md5=0c4f7ad834fb0b94f88816ce5e85dcb2
- 60 Haruta, M. ; Yamada, N. ; Kobayashi, T. ; Iijima, S. Gold Catalysts Prepared by Coprecipitation for Low-Temperature Oxidation of Hydrogen and of Carbon Monoxide . J. Catal. 1989 , 115 , 301 – 309 , DOI: 10.1016/0021-9517(89)90034-1 Google Scholar 60 Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S. Journal of Catalysis ( 1989 ), 115 ( 2 ), 301-9 CODEN: JCTLA5 ; ISSN: 0021-9517 . Novel Au catalysts were prepd. by copptn. from an aq. soln. of HAuCl4 and the nitrates of various transition metals. Calcination of the coppts. in air at 400° produced ultrafine Au particles <10 nm which were uniformly dispersed on the transition metal oxides. Among them, Au/α-Fe2O3, Au/Co3O4, and Au/NiO were highly active for H2 and CO oxidn., showing markedly enhanced catalytic activities due to the combined effect of Au and the transition metal oxides. For the oxidn. of CO they were active even at a temp. as low as -70°. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhtVamsbY%253D&md5=e5251756c7ba5548ab855a97d979cce4
- 61 Lisiecki, I. ; Pileni, M. P. Synthesis of Copper Metallic Clusters Using Reverse Micelles as Microreactors . J. Am. Chem. Soc. 1993 , 115 , 3887 – 3896 , DOI: 10.1021/ja00063a006 Google Scholar 61 Synthesis of copper metallic clusters using reverse micelles as microreactors Lisiecki, I.; Pileni, M. P. Journal of the American Chemical Society ( 1993 ), 115 ( 10 ), 3887-96 CODEN: JACSAT ; ISSN: 0002-7863 . Reverse micelles were used to synthesize in situ nanometallic Cu particles. Metallic Cu particles are formed in mixed reverse micelles with N2H4 as the reducing agent. Small particles are obtained at low H2O content. The size of the metallic cluster increases 2-10 nm with increasing H2O content. The use of pure Cu surfactant mols. instead of mixed micelles favors the formation of cylindrical metallic particles. Large metallic Cu particles (20-28 nm) are formed by using NaBH4 as a reducing agent (in the absence of O and at low H2O content). The metallic clusters progressively disappear, forming instead Cu oxide particles with increasing H2O content. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVWksLo%253D&md5=8c8d4c3d9895995445147fa5dadd4c99
- 62 Jun, S. H. ; Cha, S. H. ; Kim, J. ; Cho, S. ; Park, Y. Crystalline Silver Nanoparticles by Using Polygala Tenuifolia Root Extract as a Green Reducing Agent . J. Nanosci. Nanotechnol. 2015 , 15 , 1567 – 1574 , DOI: 10.1166/jnn.2015.9031 Google Scholar 62 Crystalline silver nanoparticles by using Polygala tenuifolia root extract as a green reducing agent Jun, Sang Hui; Cha, Song-Hyun; Kim, Jinwoong; Cho, Seonho; Park, Youmie Journal of Nanoscience and Nanotechnology ( 2015 ), 15 ( 2 ), 1567-1574 CODEN: JNNOAR ; ISSN: 1533-4880 . ( American Scientific Publishers ) Due to the emergence of multidrug-resistant bacteria, silver nanoparticles (AgNPs) have found interest as a new category of antibacterial agents. The toxicity of the chems. involved in the commonly employed chem. methods for synthesizing AgNPs present limitations for subsequent pharmaceutical and biomedical applications. In this report, 70% aq. ethanol exts. of Polygala tenuifolia root were used to reduce Ag+1 ions for AgNPs synthesis. The as-synthesized AgNPs were characterized via UV-Visible spectrophotometry, high resoln. transmission electron microscopy, at. force microscopy, X-ray diffraction, and Fourier transform IR spectroscopy. A strong surface plasmon resonance band was obsd. at 414 nm. Images from the high resoln. transmission electron microscopy and at. force microscopy demonstrated the spherical and irregular shapes of the AgNPs were synthesized. The AgNP cryst. structure was confirmed by the strong diffraction peaks in the X-ray diffraction results and by the bright circular spots obsd. in selected-area electron diffraction, whose av. diam. was measured to be 17.97 ± 8.63 nm or 15.12 nm via high resoln. transmission electron microscopy images or X-ray diffraction anal., resp. The as-synthesized AgNPs exerted the highest antibacterial activity against Escherichia coli among the tested Gram-pos. and Gram-neg. bacteria. The current method is eco-friendly, straight-forward, cost-effective, biocompatible, and easily scaled up to produce of AgNPs for applications in the treatment of bacterial infections. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXls1Cms7g%253D&md5=03bc61b74be2f0f6c00573ad799b5e91
- 63 Zhang, Q. W. ; Lin, L. G. ; Ye, W. C. Techniques for Extraction and Isolation of Natural Products: A Comprehensive Review . Chinese Medicine 2018 , DOI: 10.1186/s13020-018-0177-x Google Scholar There is no corresponding record for this reference.
- 64 El Maaiden, E. ; Bouzroud, S. ; Nasser, B. ; Moustaid, K. ; El Mouttaqi, A. ; Ibourki, M. ; Boukcim, H. ; Hirich, A. ; Kouisni, L. ; El Kharrassi, Y. A Comparative Study between Conventional and Advanced Extraction Techniques: Pharmaceutical and Cosmetic Properties of Plant Extracts . Molecules 2022 , 27 , 2074 , DOI: 10.3390/molecules27072074 Google Scholar 64 A Comparative Study between Conventional and Advanced Extraction Techniques: Pharmaceutical and Cosmetic Properties of Plant Extracts El Maaiden, Ezzouhra; Bouzroud, Sarah; Nasser, Boubker; Moustaid, Khadija; El Mouttaqi, Ayoub; Ibourki, Mohamed; Boukcim, Hassan; Hirich, Abdelaziz; Kouisni, Lamfeddal; El Kharrassi, Youssef Molecules ( 2022 ), 27 ( 7 ), 2074 CODEN: MOLEFW ; ISSN: 1420-3049 . ( MDPI AG ) This study aimed to compare the influence of extn. methods on the pharmaceutical and cosmetic properties of medicinal and arom. plants (MAPs). For this purpose, the dried plant materials were extd. using advanced (microwave (MAE), ultrasonic (UAE), and homogenizer (HAE) assisted extns.) and conventional techniques (maceration, percolation, decoction, infusion, and Soxhlet). The tyrosinase, elastase, α-amylase, butyryl, and acetylcholinesterase inhibition were tested by using L-3,4 dihydroxy-phenylalanine, N-Succinyl-Ala-Ala-p-nitroanilide, butyryl, and acetylcholine as resp. substrates. Antioxidant activities were studied by ABTS, DPPH, and FRAP. In terms of extn. yield, advanced extn. techniques showed the highest values (MAE > UAE > HAE). Chem. profiles were dependent on the phenolic compds. tested, whereas the antioxidant activities were always higher, mainly in infusion and decoction as a conventional technique. In relation to the pharmaceutical and cosmetic properties, the highest inhibitory activities against α-amylase and acetylcholinesterase were obsd. for Soxhlet and macerated exts., whereas the highest activity against tyrosinase was obtained with MAE > maceration > Soxhlet. Elastase and butyrylcholinesterase inhibitory activities were in the order of Soxhlet > maceration > percolation, with no activities recorded for the other tested methods. In conclusion, advanced methods afford an ext. with high yield, while conventional methods might be an adequate approach for minimal changes in the biol. properties of the ext. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtVejs77E&md5=243d2c52e13b4d8ba315a9beb12800c3
- 65 Saifullah, M. ; McCullum, R. ; McCluskey, A. ; Vuong, Q. Comparison of Conventional Extraction Technique with Ultrasound Assisted Extraction on Recovery of Phenolic Compounds from Lemon Scented Tea Tree (Leptospermum Petersonii) Leaves . Heliyon 2020 , 6 , e03666 DOI: 10.1016/j.heliyon.2020.e03666 Google Scholar There is no corresponding record for this reference.
- 66 Fotsing Yannick Stéphane, F. ; Kezetas Jean Jules, B. ; El-Saber Batiha, G. ; Ali, I. ; Ndjakou Bruno, L. Extraction of Bioactive Compounds from Medicinal Plants and Herbs ; Natural Medicinal Plants , 2022 . Google Scholar There is no corresponding record for this reference.
- 67 Mahmoodi Esfanddarani, H. ; Abbasi Kajani, A. ; Bordbar, A. Green Synthesis of Silver Nanoparticles Using Flower Extract of Malva Sylvestris and Investigation of Their Antibacterial Activity . IET Nanobiotechnol 2018 , 12 , 412 – 416 , DOI: 10.1049/iet-nbt.2017.0166 Google Scholar 67 Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity Mahmoodi Esfanddarani Hassan; Abbasi Kajani Abolghasem; Bordbar Abdol-Khalegh IET nanobiotechnology ( 2018 ), 12 ( 4 ), 412-416 ISSN: 1751-8741 . High-quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic-force microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20-40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MfjvFCgtQ%253D%253D&md5=300fce194b9b6e7c092fa87366095c49
- 68 Akhtar, M. S. ; Panwar, J. ; Yun, Y. S. Biogenic Synthesis of Metallic Nanoparticles by Plant Extracts . ACS Sustainable. Chem. Eng. 2013 , 1 , 591 – 602 , DOI: 10.1021/sc300118u Google Scholar 68 Biogenic Synthesis of Metallic Nanoparticles by Plant Extracts Akhtar, Mohd Sayeed; Panwar, Jitendra; Yun, Yeoung-Sang ACS Sustainable Chemistry & Engineering ( 2013 ), 1 ( 6 ), 591-602 CODEN: ASCECG ; ISSN: 2168-0485 . ( American Chemical Society ) A review. In recent years, nanobiotechnol. has emerged as an elementary division of modern science and a novel epoch in the fields of material science and is receiving global attention due to its ample applications. Various phys., chem., and biol. methods have been employed to synthesize nanomaterials. Biol. systems such as bacteria, fungi, actinomycetes, yeasts, viruses, and plants have been reported to synthesize various metal and metal oxide nanoparticles. Among these, biosynthesis of nanoparticles from plants seems to be a very effective method in developing a rapid, clean, nontoxic, and eco-friendly technol. The use of plant biomass or exts. for the biosynthesis of novel metal nanoparticles (silver, gold, platinum, and palladium) would be more significant if the nanoparticles were synthesized extracellularly and in a controlled manner according to their dispersity of shape and size. Owing to the rich biodiversity of plants, their potential use toward the synthesis of these noble metal nanoparticles is yet to be explored. The aim of this review is to provide the recent trends involved in the phytosynthesis of nobel metal nanoparticles in the past decade. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltVCksr0%253D&md5=1bd67ecddd252fff33d1735637a20a05
- 69 Saravanakumar, K. ; Chelliah, R. ; Shanmugam, S. ; Varukattu, N. B. ; Oh, D. H. ; Kathiresan, K. ; Wang, M. H. Green Synthesis and Characterization of Biologically Active Nanosilver from Seed Extract of Gardenia Jasminoides Ellis . Journal of Photochemistry and Photobiology B: Biology 2018 , 185 , 126 – 135 , DOI: 10.1016/j.jphotobiol.2018.05.032 Google Scholar 69 Green synthesis and characterization of biologically active nanosilver from seed extract of Gardenia jasminoides Ellis Saravanakumar, Kandasamy; Chelliah, Ramachandran; Shanmugam, Sabarathinam; Varukattu, Nipun Babu; Oh, Deog-Hwan; Kathiresan, Kandasamy; Wang, Myeong-Hyeon Journal of Photochemistry and Photobiology, B: Biology ( 2018 ), 185 ( ), 126-135 CODEN: JPPBEG ; ISSN: 1011-1344 . ( Elsevier B.V. ) This article reports the utilization of seed ext. (GSE) from Gardenia jasminoides Ellis. in the synthesis of silver nanoparticles (Gs-AgNPs) with versatile biol. activities. The synthesized Gs-AgNPs were spherical in shape, crystal lattice with an av. size of 20nm as confirmed by UV-vis spectrum, X-ray diffractometer (XRD), Transmission electron microscopy with Energy dispersive X-ray spectroscopy (TEM-EDS) and particle size analyses (PSA). Phenolic compds., proteins, and terpenoids were likely involved in the Gs-AgNPs synthesis, as indicated by Fourier-transform IR spectroscopy (FTIR) anal. The MBC of the Gs-AgNPs induced >70% bacterial cell death within 60min, as confirmed by growth curve anal. followed by Confocal laser scanning microscope (CLSM). Gs-AgNPs showed the highest scavenging activity for 1, 2-diphenyl-1-picrylhydrazyl DPPH radical (92.3±0.86%), Nitric oxide (NO) radical (72.5±2.15%), and Hydrogen peroxide H2O2 radical (85.25±1.45%). The Gs-AgNPs generated high reactive oxygen species (ROS) resulting in induced apoptosis as evident by up-regulation of apoptosis-related protein. In addn., the photocatalytic results revealed about 92% of the redn. in Coomassie Brilliant Blue dye color with Gs-AgNPs. Hence, this work provided economically viable and ecol. sustainable Gs-AgNPs as an alternative biomaterial for future therapeutic applications as antimicrobial, antioxidant, anti-cancer agents and in dye degrdn. for water remediation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtFSgt7nL&md5=941c5fb8bad3a6e720f4595445e0b207
- 70 Behravan, M. ; Hossein Panahi, A. ; Naghizadeh, A. ; Ziaee, M. ; Mahdavi, R. ; Mirzapour, A. Facile Green Synthesis of Silver Nanoparticles Using Berberis Vulgaris Leaf and Root Aqueous Extract and Its Antibacterial Activity . Int. J. Biol. Macromol. 2019 , 124 , 148 – 154 , DOI: 10.1016/j.ijbiomac.2018.11.101 Google Scholar 70 Facile green synthesis of silver nanoparticles using Berberis vulgaris leaf and root aqueous extract and its antibacterial activity Behravan, Mahmoodreza; Hossein Panahi, Ayat; Naghizadeh, Ali; Ziaee, Masood; Mahdavi, Roya; Mirzapour, Aliyar International Journal of Biological Macromolecules ( 2019 ), 124 ( ), 148-154 CODEN: IJBMDR ; ISSN: 0141-8130 . ( Elsevier B.V. ) Most recently, silver nanoparticles due to antibacterial properties have been considered in medical science. So the aim of the study was green synthesis of silver nanoparticles using Berberis vulgaris leaf and root aq. ext. and its antibacterial activity. After collection, identification and extn. of Berberis vulgaris was performed prodn. of silver nanoparticles. In the study effect of parameters such as AgNO3 concn. (0.5, 1, 3, 10 mM), aq. ext. (3, 5, 10, 15, 30 mL) and contact time (1, 2, 6, 12, 24 h) were investigated in the synthesis of nanoparticles and also the antibacterial effect of these nanoparticles was studied on Escherichia coli and Staphylococcus aureus bacteria by Disk diffusion test and Min. Inhibitory Concn. test (MIC). According to XRD results and anal. of TEM, nanoparticles have spherical shapes and size of 30 to 70 nm. On the other hand antibacterial tests showed these nanoparticles have more antibacterial activity more than other exts. Result showed the biosynthesis of silver nanoparticles using aq. ext. of Berberis vulgaris is a clean, inexpensive and safe method that has not been used any toxic substance and consequently does not side effects and this nanoparticles has a high antibacterial activity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlenu7%252FN&md5=aaa414ca2a6cbc26f6885014c0226f29
- 71 Fardsadegh, B. ; Jafarizadeh-Malmiri, H. Aloe Vera Leaf Extract Mediated Green Synthesis of Selenium Nanoparticles and Assessment of Their in Vitro Antimicrobial Activity against Spoilage Fungi and Pathogenic Bacteria Strains . Green. Process. Synth. 2019 , 8 , 399 – 407 , DOI: 10.1515/gps-2019-0007 Google Scholar 71 Aloe vera leaf extract mediated green synthesis of selenium nanoparticles and assessment of their In vitro antimicrobial activity against spoilage fungi and pathogenic bacteria strains Fardsadegh, Borna; Jafarizadeh-Malmiri, Hoda Green Processing and Synthesis ( 2019 ), 8 ( 1 ), 399-407 CODEN: GPSREC ; ISSN: 2191-9550 . ( Walter de Gruyter GmbH ) Selenium as an essential trace element for the health of the humans was used to hydrothermally synthesis of selenium nanoparticle (Se NPs) using Aloe vera leaf ext. (ALE). Effects of synthesis parameters namely; amt. of ALE (1-5 mL) and amt. of Na2SeO3 soln. (10-30 mL), on the particle size and color intensity of the soln. contg. Se NPs were studied using response surface methodol. FT-IR spectroscopy, UV-Vis spectrophotometry, DLS analyzer and TEM were used to det. the specifications of the ALE and synthesized Se NPs. Obtained results indicated that the ALE contained several bioactive compds., which they had hydroxyl and amide I groups in their structures and these two functional groups had key roles in the redn. of the selenium ions to form Se NPs and stabilizing of them. Furthermore, spherical fabricated Se NPs using obtained optimum synthesis parameters, 4.92 mL of ALE and 13.03 mL of Na2SeO3 soln., had color intensity, mean particle size, zeta potential and polydispersity index values of 3.0% a.u., 50 nm, -18 mV and 0.344, resp. according to the DLS anal. The synthesized Se NPs had also high antibacterial and antifungal activities against 4 selected pathogenic bacteria and spoilage fungi strains. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitlansbjL&md5=c151c16ba3be0c2264308a1d316be85e
- 72 Bergeson, L. L. Sustainable Nanomaterials: Emerging Governance Systems . ACS Sustainable. Chem. Eng. 2013 , 1 , 724 – 730 , DOI: 10.1021/sc4000863 Google Scholar 72 Sustainable Nanomaterials: Emerging Governance Systems Bergeson, Lynn L. ACS Sustainable Chemistry & Engineering ( 2013 ), 1 ( 7 ), 724-730 CODEN: ASCECG ; ISSN: 2168-0485 . ( American Chemical Society ) A review concerning domestic and international laws, regulations, policies, and government and private-party governance programs and oversight systems to assess regulatory initiatives addressing potential enhancement of nanomaterial risks and their utility to nurture commercialization of nanoscale materials, is given. Whether existing laws are adequate to address potential risks from nanoscale materials and promote their sustainable use will inspire debate and governance initiatives for years to come. Topics discussed include: background; green nanotechnol.; emerging governance frameworks (adequacy of existing legal authorities, federal regulatory initiatives, state and local regulatory initiatives, key std.-setting initiatives, key private-sector stewardship initiatives [describe material and application; profile life cycle(s); evaluate risks; assess risk management;, decide, document, and act; review and adapt]); fostering and promoting green nanotechnol. (develop a life cycle assessment appropriate for green nanoproducts, establish performance and branding stds. for green nanotechnol., provide tax and related business incentives to innovators to encourage application of green nanotechnol., increase patent term protection for green nanoproducts, establish a Design for Environment green nano category, provide greater funding for green nano research, convene a forum to develop and implement green nano principles in a systematic way, actively promote green nano in regulatory and voluntary initiatives); and conclusions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpsFWqsL8%253D&md5=fd2c1e765ac035e1ea932392c30e0145
- 73 Hutchison, J. E. Greener Nanoscience: A Proactive Approach to Advancing Applications and Reducing Implications of Nanotechnology . ACS Nano 2008 , 2 , 395 – 402 , DOI: 10.1021/nn800131j Google Scholar 73 Greener Nanoscience: A Proactive Approach to Advancing Applications and Reducing Implications of Nanotechnology Hutchison, James E. ACS Nano ( 2008 ), 2 ( 3 ), 395-402 CODEN: ANCAC3 ; ISSN: 1936-0851 . ( American Chemical Society ) Nanotechnol. continues to offer new materials and applications that will benefit society, yet there is growing concern about the potential health and environmental impacts of prodn. and use of nanoscale products. Although hundreds of studies of nanomaterial hazards were reported, due (largely) to the complexity of the nanomaterials, there is no consensus about the impact these hazards will have. This focus describes the need for a research agenda that addresses these nanomaterial complexities through coordinated research on the applications and implications of new materials, wherein nanomaterials scientists play a central role in the move from understanding to minimizing nanomaterial hazards. Greener nanoscience is presented as an approach to detg. and implementing the design rules for safer nanomaterials and safer, more efficient processes. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjsF2ktLo%253D&md5=df5c52801fb2a75d813aad46c6d230d8
- 74 Dahl, J. A. ; Maddux, B. L. S. ; Hutchison, J. E. Toward Greener Nanosynthesis . Chem. Rev. 2007 , 107 , 2228 – 2269 , DOI: 10.1021/cr050943k Google Scholar 74 Toward Greener Nanosynthesis Dahl, Jennifer A.; Maddux, Bettye L. S.; Hutchison, James E. Chemical Reviews (Washington, DC, United States) ( 2007 ), 107 ( 6 ), 2228-2269 CODEN: CHREAY ; ISSN: 0009-2665 . ( American Chemical Society ) A review of application of green chem. principles in nanosynthesis. Green nanoscience, application of the principles of green chem. to nanoscience,toward greener synthetic methods for functionalized metal nanoparticles (citrate reactions, direct synthesis of ligand-stabilized nanoparticles, seeded growth and shape control of nanoparticles, and emerging approaches in nanoparticle synthesis), toward greener prepns. of semiconductor and inorg. oxide nanoparticles (cadmium selenide and cadmium sulfide, zinc nanoparticles, and iron oxides), alternate solvents and energy source for nanoparticle synthesis (supercrit. fluids, ionic liqs., sonochem., laser ablation, and microwave), bio-based approaches (shape control with biomols., and whole organism approaches), functionalization (postsynthetic modification of the ligand shell, and ligand exchange), and nanoparticle assembly (assembly of extended nanoparticle-based array in soln. and directed assembly on surfaces and scaffolds) are considered. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXmtlaks7s%253D&md5=7f9114f08863ae6d684bff60d78a65e7
- 75 Korbekandi, H. ; Iravani, S. ; Abbasi, S. Production of Nanoparticles Using Organisms . Crit. Rev. Biotechnol. 2009 , 29 , 279 – 306 , DOI: 10.3109/07388550903062462 Google Scholar 75 Production of nanoparticles using organisms Korbekandi, Hassan; Iravani, Siavash; Abbasi, Sajjad Critical Reviews in Biotechnology ( 2009 ), 29 ( 4 ), 279-306 CODEN: CRBTE5 ; ISSN: 0738-8551 . ( Informa Healthcare ) A review. Recent developments in the biosynthesis of nanomaterials have demonstrated the important role of biol. systems and microorganisms in nanoscience and nanotechnol. These organisms show a unique potential in environmentally friendly prodn. and accumulation of nanoparticles with different shapes and sizes. Therefore, researchers in the field of nanoparticle synthesis are focusing their attention to biol. systems. In order to obtain different applied chem. compns., controlled monodispersity, desired morphologies (e.g., amorphous, spherical, needles, cryst., triangular, and hexagonal), and interested particle size, they have investigated the biol. mechanism and enzymic process of nanoparticle prodn. In this review, most of these organisms used in nanoparticle synthesis are shown. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyjtLfP&md5=6c24aa5f16cde3070d4d82f99bdef4a8
- 76 Virkutyte, J. ; Varma, R. S. Green Synthesis of Nanomaterials: Environmental Aspects . ACS Symp. Ser. 2013 , 11–39 . Google Scholar There is no corresponding record for this reference.
- 77 Sujoy, K. ; Marsili, E. Bioinspired Metal Nanoparticle: Synthesis, Properties and Application . Nanomaterials 2011 , DOI: 10.5772/25305 Google Scholar There is no corresponding record for this reference.
- 78 Fabrega, J. ; Luoma, S. N. ; Tyler, C. R. ; Galloway, T. S. ; Lead, J. R. Silver Nanoparticles: Behaviour and Effects in the Aquatic Environment . Environ. Int. 2011 , 37 , 517 – 531 , DOI: 10.1016/j.envint.2010.10.012 Google Scholar 78 Silver nanoparticles: Behaviour and effects in the aquatic environment Fabrega, Julia; Luoma, Samuel N.; Tyler, Charles R.; Galloway, Tamara S.; Lead, Jamie R. Environment International ( 2011 ), 37 ( 2 ), 517-531 CODEN: ENVIDV ; ISSN: 0160-4120 . ( Elsevier Ltd. ) This review summaries and evaluates the present knowledge on the behavior, the biol. effects and the routes of uptake of silver nanoparticles (Ag NPs) to organisms, with considerations on the nanoparticle physicochem. in the ecotoxicity testing systems used. Different types of Ag NP syntheses, characterization techniques and predicted current and future concns. in the environment are also outlined. Rapid progress in this area has been made over the last few years, but there is still a crit. lack of understanding of the need for characterization and synthesis in environmental and ecotoxicol. studies. Concn. and form of nanomaterials in the environment are difficult to quantify and methodol. progress is needed, although sophisticated exposure models show that predicted environmental concns. (PECs) for Ag NPs in different environmental compartments are at the range of ng L-1 to mg kg-1. The ecotoxicol. literature shows that concns. of Ag NPs below the current and future PECs, as low as just a few ng L-1, can affect prokaryotes, invertebrates and fish indicating a significant potential, though poorly characterized, risk to the environment. Mechanisms of toxicity are still poorly understood although it seems clear that in some cases nanoscale specific properties may cause biouptake and toxicity over and above that caused by the dissolved Ag ion. This review concludes with a set of recommendations for the advancement of understanding of the role of nanoscale silver in environmental and ecotoxicol. research. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFCjtr8%253D&md5=01ba858a5e7e8496b7a875d075af5ae8
- 79 Hassellöv, M. ; Readman, J. W. ; Ranville, J. F. ; Tiede, K. Nanoparticle Analysis and Characterization Methodologies in Environmental Risk Assessment of Engineered Nanoparticles . Ecotoxicology 2008 , 17 , 344 – 361 , DOI: 10.1007/s10646-008-0225-x Google Scholar 79 Nanoparticle analysis and characterization methodologies in environmental risk assessment of engineered nanoparticles Hassellov Martin; Readman James W; Ranville James F; Tiede Karen Ecotoxicology (London, England) ( 2008 ), 17 ( 5 ), 344-61 ISSN: 0963-9292 . Environmental risk assessments of engineered nanoparticles require thorough characterization of nanoparticles and their aggregates. Furthermore, quantitative analytical methods are required to determine environmental concentrations and enable both effect and exposure assessments. Many methods still need optimization and development, especially for new types of nanoparticles in water, but extensive experience can be gained from the fields of environmental chemistry of natural nanomaterials and from fundamental colloid chemistry. This review briefly describes most methods that are being exploited in nanoecotoxicology for analysis and characterization of nanomaterials. Methodological aspects are discussed in relation to the fields of nanometrology, particle size analysis and analytical chemistry. Differences in both the type of size measures (length, radius, aspect ratio, etc.), and the type of average or distributions afforded by the specific measures are compared. The strengths of single particle methods, such as electron microscopy and atomic force microscopy, with respect to imaging, shape determinations and application to particle process studies are discussed, together with their limitations in terms of counting statistics and sample preparation. Methods based on the measurement of particle populations are discussed in terms of their quantitative analyses, but the necessity of knowing their limitations in size range and concentration range is also considered. The advantage of combining complementary methods is highlighted. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czktFOitA%253D%253D&md5=9cc89abcea0d3c24b5f762b70ef75d83
- 80 Stuart, B. H. Biological Applications of Infrared Spectroscopy ; John Wiley & Sons , 1997 . Google Scholar There is no corresponding record for this reference.
- 81 Lee, D. C. ; Chapman, D. Infrared Spectroscopic Studies of Biomembranes and Model Membranes . Biosci. Rep. 1986 , 6 , 235 – 256 , DOI: 10.1007/BF01115153 Google Scholar 81 Infrared spectroscopic studies of biomembranes and model membranes Lee, David C.; Chapman, Dennis Bioscience Reports ( 1986 ), 6 ( 3 ), 235-56 CODEN: BRPTDT ; ISSN: 0144-8463 . A review with many refs. The application of IR spectroscopy to the study of membrane lipids, membrane proteins, and lipid-protein interactions is discussed. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28Xktlynsrs%253D&md5=e90a984efbc1bfa73ba717e4082e8bc1
- 82 Schmitt, J. ; Flemming, H. C. FTIR-Spectroscopy in Microbial and Material Analysis . Int. Biodeterior. Biodegrad. 1998 , 41 , 1 – 11 , DOI: 10.1016/S0964-8305(98)80002-4 Google Scholar 82 FTIR-spectroscopy in microbial and material analysis Schmitt, Jurgen; Flemming, Hans-Curt International Biodeterioration & Biodegradation ( 1998 ), 41 ( 1 ), 1-11 CODEN: IBBIES ; ISSN: 0964-8305 . ( Elsevier Science Ltd. ) The investigation of the development and the properties of biofilms is difficult because classical microbiol. does not offer non-destructive methods other than microscopical observations. This paper discusses the use of different Fourier transform IR spectroscopy (FTIR-spectroscopy) techniques as a means to investigate microorganisms in biofilms. FTIR-spectroscopy is suitable for the identification of microorganisms and presents a new addn. to taxonomic and genetic methods. The FTIR anal. of bacterial isolates provides fingerprint spectra, allowing the rapid characterization of microbial strains. Secondly, the FTIR-attenuated total reflection (ATR) technique can be used for the observation of biofilms forming directly on the interface of an ATR crystals such as germanium. These crystals can be coated to obtain a surface more relevant to study interfacial processes. Spectra can be acquired non-destructively, in situ and in real time. This method is suitable for fundamental biofilm research, as well as for monitoring of biofilm formation, e.g., in an ultrapure or drinking water systems. Furthermore, FTIR-ATR also allows the rapid anal. of deposits on surfaces, e.g., filtration membranes. The anal. discrimination between microorganisms, inorg. material or other foulants can be obtained. Thirdly, with the diffuse reflectance technique (DRIFT) it is possible to investigate reflecting surfaces like metals or very small samples. The compn. of surface coatings like biomass or other surface contaminants can be detected. These different measurement techniques demonstrate that FTIR -spectroscopy is suitable for biofilm and surface anal. and can be applied in many different ways. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXktFOkt74%253D&md5=5fa35e7f310a6ea30c914c4994aea6f0
- 83 Mathieu, J. P. Optics ; Pergamon Press : Oxford, NY , 1975 . Google Scholar There is no corresponding record for this reference.
- 84 Rani, P. ; Kumar, V. ; Singh, P. P. ; Matharu, A. S. ; Zhang, W. ; Kim, K. H. ; Singh, J. ; Rawat, M. Highly Stable AgNPs Prepared via a Novel Green Approach for Catalytic and Photocatalytic Removal of Biological and Non-Biological Pollutants . Environ. Int. 2020 , 143 , 105924 , DOI: 10.1016/j.envint.2020.105924 Google Scholar 84 Highly stable AgNPs prepared via a novel green approach for catalytic and photocatalytic removal of biological and non-biological pollutants Rani, Pooja; Kumar, Vanish; Singh, Prit Pal; Matharu, Avtar Singh; Zhang, Wei; Kim, Ki-Hyun; Singh, Jagpreet; Rawat, Mohit Environment International ( 2020 ), 143 ( ), 105924 CODEN: ENVIDV ; ISSN: 0160-4120 . ( Elsevier Ltd. ) Increases in biol. and non-biol. pollutants pose a significant threat to environmental systems. In an effort to develop an effective means to treat such pollutants, the use of Phaseolus vulgaris (kidney beans) as reducing and capping agents is proposed for the green synthesis of highly stable silver nanoparticles (AgNPs) with a face-centered cubic (fcc) cryst. structure (size range: 10-20 nm). The potent role of the resulting AgNPs was found as triple platforms (photocatalyst, catalyst, and antimicrobial disinfectant). AgNPs were able to photocatalytically degrade approx. 97% of reactive red-141 (RR-141) dye within 150 min of exposure (quantum efficiency of 3.68 x 10-6 mol.photon-1 and a removal reaction kinetic rate of 1.13 x 10-2 mmol g-1 h-1). The role of specific reactive oxygen species (ROS) in the photocatalytic process and complete mineralization of dye was also explored through scavenger and COD (COD) expts., resp. As an catalyst, AgNPs were also capable of reducing 4-nitrophenol to 4-aminophenol within 15 min. Overall, AgNPs showed excellent stability as catalyst and photocatalyst even after five test cycles. As an antimicrobial agent, the AgNPs are effective against both gram-pos. (Bacillus subtilis) and -neg. bacteria (Escherichia coli), with the zones of clearance as 15 and 18 mm, resp. Thus, the results of this study validate the triple role of AgNPs derived via green synthesis as a photocatalyst, catalyst, and antimicrobial agent for effective environmental remediation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2isbjJ&md5=663bc1cac04b4282fb262b311aad405d
- 85 Uddin, A. K. M. R. ; Siddique, M. A. B. ; Rahman, F. ; Ullah, A. K. M. A. ; Khan, R. Cocos Nucifera Leaf Extract Mediated Green Synthesis of Silver Nanoparticles for Enhanced Antibacterial Activity . J. Inorg. Organomet. Polym. Mater. 2020 , 30 , 3305 – 3316 , DOI: 10.1007/s10904-020-01506-9 Google Scholar 85 Cocos nucifera Leaf Extract Mediated Green Synthesis of Silver Nanoparticles for Enhanced Antibacterial Activity Uddin, A. K. M. Royhan; Siddique, Md. Abu Bakar; Rahman, Farjana; Ullah, A. K. M. Atique; Khan, Rahat Journal of Inorganic and Organometallic Polymers and Materials ( 2020 ), 30 ( 9 ), 3305-3316 CODEN: JIOPAY ; ISSN: 1574-1443 . ( Springer ) In this work, we have successfully green synthesized the AgNPs using Cocos nucifera leaf aq. ext. as the natural reducing and stabilizing agent, and aq. silver nitrate (AgNO3) soln. as a precursor by a newly developed technique. The synthesized AgNPs were identified by XRD anal. as a cubic crystal system with an av. crystallite size of 14.2 nm. The aq. colloidal suspension of AgNPs shows a UV-Vis absorption maxima of 380 nm indicating its formation. FT-IR anal. identified the C-N, -OH and N-H as the major and probable functional groups in the leaf ext. responsible for the prodn. of stable AgNPs. The results of antibacterial studies of the material showed the considerable zones of inhibition against both Gram-pos. (Staphylococcus aureus and Bacillus subtilis) and Gram-neg. (Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Citrobacter freundii) bacteria ranging from 10 to 20 mm with less inhibition for the former than the latter. The max. (20 mm) and min. (10 mm) inhibition zone was shown by C. freundii and Bacillus subtilis, resp. and P. aeruginosa shows the second-highest zone of inhibition (19 mm). The antibacterial performance of the material implies that the C. nucifera leaf ext. mediated green synthesized AgNPs can be regarded as a potential candidate for antimicrobial application appreciably. Graphic Abstr.: [graphic not available: see fulltext]. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlt1WjtL0%253D&md5=1a81ec1aa941f16fa2073577f7280bac
- 86 AlMasoud, N. ; Alomar, T. S. ; Awad, M. A. ; El-Tohamy, M. F. ; Soliman, D. A. Multifunctional green silver nanoparticles in pharmaceutical and biomedical applications . Green Chem. Lett. Rev. 2020 , 13 , 316 – 327 , DOI: 10.1080/17518253.2020.1839572 Google Scholar 86 Multifunctional green silver nanoparticles in pharmaceutical and biomedical applications Almasoud, Najla; Alomar, Taghrid S.; Awad, Manal A.; El-Tohamy, Maha F.; Soliman, Dina A. Green Chemistry Letters and Reviews ( 2020 ), 13 ( 4 ), 316-327 CODEN: GCLRAI ; ISSN: 1751-7192 . ( Taylor & Francis Ltd. ) The present study concerned with the use of an aq. ginger ext. as naturally and ecofriendly reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs). The unique physicochem. characteristics of green synthesized AgNPs exhibit high potential antimicrobial activity and displayed an impact role in pharmaceutical detns. To confirm the nanoscale of green synthesized AgNPs, various microscopic and spectroscopic techniques were performed. The synthesized nanoparticles were screened for their antimicrobial activity against several strains of bacteria and fungi. The obtained results showed excellent bactericidal and fungicidal effects. Also, the spectrofluorimetric anal. of anastrozole drug in bulk powder and dosage form was investigated. The suggested method displayed linear relationship between the drug concns. and the fluorescence intensity between 2 and 100μgmL-1 with regression equation was IFL = 9.1917C+ 65.945, n = 10 and r = 0.9995 at λex 390 and λem 440 nm. The green synthesized AgNPs using ginger ext. demonstrated a potential activity in pharmaceutical and biomedical fields. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXjsFKqtw%253D%253D&md5=fe81995e83d8a86342eeb7a46e1d9cfb
- 87 Awad, M. A. ; Hendi, A. ; Ortashi, K. M. ; Alzahrani, B. ; Soliman, D. ; Alanazi, A. ; Alenazi, W. ; Taha, R. M. ; Ramadan, R. ; El-Tohamy, M. ; AlMasoud, N. ; Alomar, T. S. Biogenic Synthesis of Silver Nanoparticles Using Trigonella Foenum-Graecum Seed Extract: Characterization, Photocatalytic and Antibacterial Activities . Sensors and Actuators A: Physical 2021 , 323 , 112670 , DOI: 10.1016/j.sna.2021.112670 Google Scholar 87 Biogenic synthesis of silver nanoparticles using Trigonella foenum-graecum seed extract: Characterization, photocatalytic and antibacterial activities Awad, Manal A.; A. Hendi, Awatif; Ortashi, Khalid Mustafa; Alzahrani, Batool; Soliman, Dina; Alanazi, Amnah; Alenazi, Wadha; Taha, Rasha Mohammed; Ramadan, Rasha; El-Tohamy, Maha; AlMasoud, Najla; Alomar, Taghrid S. Sensors and Actuators, A: Physical ( 2021 ), 323 ( ), 112670 CODEN: SAAPEB ; ISSN: 0924-4247 . ( Elsevier B.V. ) A biogenic approach in the synthesis of nanoparticles has been the current trend in nanoscience attributed to the fact that it is an environmentally benign process which is safe to be used in biomedical applications. The present study describes a green mode of synthesis of silver nanoparticles using Trigonella foenum-graecum(fenugreek) with minimal scale size and ultra-stable features. The synthesized nanoparticles were characterized using UV-vis spectroscopy which showed a max. absorption peak at 443 nm. The electronmicrographs of transmission and scanning electron microscopes predominantly spherical and not aggregated nanoparticles with an irregular array of an av. diam. of 82.53 nm. The photocatalytic activity of silver nanoparticles was assessed by depredating Rhodamine B dye under light irradn. The photodegrdn. of Rhodamine B dye was time-dependent followed by a complete photodegrdn. (nearly 93%) with decoloration after 216 h. Further, the antibacterial activity of the silver nanoparticles was evaluated using three different bacterial strains and the zones of inhibition were shown to be (14, 2.0 mm), (5.0, 2.0 mm) and (10, 0.9 mm) for E. coli, S. aureus and Bacillus cereus, resp. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmtFKnur0%253D&md5=ebfa00977fa3435abc36187d38d49582
- 88 Devaraj, P. ; Kumari, P. ; Aarti, C. ; Renganathan, A. Synthesis and Characterization of Silver Nanoparticles Using Cannonball Leaves and Their Cytotoxic Activity against MCF-7 Cell Line . J. Nanotechnol. 2013 , 2013 , 1 – 5 , DOI: 10.1155/2013/598328 Google Scholar There is no corresponding record for this reference.
- 89 Capaldi Arruda, S. C. ; Diniz Silva, A. L. ; Moretto Galazzi, R. ; Antunes Azevedo, R. ; Zezzi Arruda, M. A. Nanoparticles Applied to Plant Science: A Review . Talanta 2015 , 131 , 693 – 705 , DOI: 10.1016/j.talanta.2014.08.050 Google Scholar 89 Nanoparticles applied to plant science: A review Capaldi Arruda, Sandra Cristina; Diniz Silva, Alisson Luiz; Moretto Galazzi, Rodrigo; Antunes Azevedo, Ricardo; Zezzi Arruda, Marco Aurelio Talanta ( 2015 ), 131 ( ), 693-705 CODEN: TLNTA2 ; ISSN: 0039-9140 . ( Elsevier B.V. ) A review. The present review addresses certain important aspects regarding nanoparticles and the environment, with an emphasis on plant science. The prodn. and characterization of nanoparticles is the focus of this review, providing an idea of the range and the consolidation of these aspects in the literature, with modifications on the routes of synthesis and the application of the anal. techniques for characterization of the nanoparticles (NPs). Addnl., aspects related to the interaction between the NPs and plants, their toxicities, and the phytoremediation process, among others, are also discussed. Future trends are also presented, supplying evidence for certain possibilities regarding new research involving nanoparticles and plants. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVKmsrrF&md5=51eba7f84e29e60f8d984c811aa47fb8
- 90 Oves, M. ; Aslam, M. ; Rauf, M. A. ; Qayyum, S. ; Qari, H. A. ; Khan, M. S. ; Alam, M. Z. ; Tabrez, S. ; Pugazhendhi, A. ; Ismail, I. M. I. Antimicrobial and Anticancer Activities of Silver Nanoparticles Synthesized from the Root Hair Extract of Phoenix Dactylifera . Materials Science and Engineering: C 2018 , 89 , 429 – 443 , DOI: 10.1016/j.msec.2018.03.035 Google Scholar 90 Antimicrobial and anticancer activities of silver nanoparticles synthesized from the root hair extract of Phoenix dactylifera Oves, Mohammad; Aslam, Mohammad; Rauf, Mohd. Ahmar; Qayyum, Shariq; Qari, Huda A.; Khan, Mohd. Shahnawaz; Alam, Mohammad Zubair; Tabrez, Shams; Pugazhendhi, Arivalagan; Ismail, Iqbal M. I. Materials Science & Engineering, C: Materials for Biological Applications ( 2018 ), 89 ( ), 429-443 CODEN: MSCEEE ; ISSN: 0928-4931 . ( Elsevier B.V. ) There is a continuous rise in the rate of medicine consumption because of the development of drug resistance by microbial pathogens. In the last one decade, silver nanoparticles (AgNPs) have become a remarkable choice for the development of new drugs due to their excellent broad-spectrum antimicrobial activity. In the current piece of work, we have synthesized AgNPs from the root ext. of Phoenix dactylifera to test their antimicrobial and anti-cancer potential. UV-visible spectra showed the surface plasmon resonance peak at 420 nm λmax corresponding to the formation of silver nanoparticles, FTIR spectra further confirmed the involvement of biol. moieties in AgNPs synthesis. Moreover, XRD anal. showed the cryst. nature of AgNPs and predicted the crystallite size of 15 to 40 nm. Electron microscopy analyses confirmed their spherical shape. In addn., synthesized AgNPs was also found to control the growth of C. albicans and E. coli on solid nutrient medium with 20 and 22 mm zone of inhibition, resp. The 100% potency at 40μg/mL AgNPs concn. was obsd. against E. coli and C. albicans after 4 h and 48 h incubation resp. Importantly, AgNPs were also found to decrease the cell viability of MCF7 cell lines in vitro with IC50 values of 29.6μg/mL and could act as a controlling agent of human breast cancer. Based on our results, we conclude that biol. synthesized AgNPs exhibited multifunctional properties and could be used against human cancer and other infectious diseases. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFSqt74%253D&md5=7ddd515aa4039ae844cdf5f7285e8164
- 91 Nakhjavani, M. ; Nikkhah, V. ; Sarafraz, M. M. ; Shoja, S. ; Sarafraz, M. Green Synthesis of Silver Nanoparticles Using Green Tea Leaves: Experimental Study on the Morphological, Rheological and Antibacterial Behaviour . Heat Mass Transfer 2017 , 53 , 3201 – 3209 , DOI: 10.1007/s00231-017-2065-9 Google Scholar 91 Green synthesis of silver nanoparticles using green tea leaves: Experimental study on the morphological, rheological and antibacterial behaviour Nakhjavani, Maryam; Nikkhah, V.; Sarafraz, M. M.; Shoja, Saeed; Sarafraz, Marzieh Heat and Mass Transfer ( 2017 ), 53 ( 10 ), 3201-3209 CODEN: HMTRF8 ; ISSN: 0947-7411 . ( Springer ) In this paper, silver nanoparticles are produced via green synthesis method using green tea leaves. The introduced method is cost-effective and available, which provides condition to manipulate and control the av. nanoparticle size. The produced particles were characterized using x-ray diffraction, scanning electron microscopic images, UV visualization, digital light scattering, zeta potential measurement and thermal cond. measurement. Results demonstrated that the produced samples of silver nanoparticles are pure in structure (based on the x-ray diffraction test), almost identical in terms of morphol. (spherical and to some extent cubic) and show longer stability when dispersed in deionized water. The UV-visualization showed a peak in 450 nm, which is in accordance with the previous studies reported in the literature. Results also showed that small particles have higher thermal and antimicrobial performance. As green tea leaves are used for extg. the silver nanoparticles, the method is eco-friendly. The thermal behavior of silver nanoparticle was also analyzed by dispersing the nanoparticles inside the deionized water. Results showed that thermal cond. of the silver nano-fluid is higher than that of obtained for the deionized water. Activity of Ag nanoparticles against some bacteria was also examd. to find the suitable antibacterial application for the produced particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsV2qurk%253D&md5=7e6c7b1bc7664cc1e1c6834c048fec48
- 92 Sastry, M. ; Patil, V. ; Sainkar, S. R. Electrostatically Controlled Diffusion of Carboxylic Acid Derivatized Silver Colloidal Particles in Thermally Evaporated Fatty Amine Films . J. Phys. Chem. B 1998 , 102 , 1404 – 1410 , DOI: 10.1021/jp9719873 Google Scholar 92 Electrostatically Controlled Diffusion of Carboxylic Acid Derivatized Silver Colloidal Particles in Thermally Evaporated Fatty Amine Films Sastry, Murali; Patil, Vijaya; Sainkar, S. R. Journal of Physical Chemistry B ( 1998 ), 102 ( 8 ), 1404-1410 CODEN: JPCBFK ; ISSN: 1089-5647 . ( American Chemical Society ) It was recently demonstrated that carboxylic acid derivatized silver colloidal particles can be incorporated in thermally evapd. fatty amine films by immersion of the films in the silver sol and that the process is controlled through electrostatic interactions (M. Sastry et. al. (1997)). In this paper, the influence of colloidal particle concn., soln. pH, and film thickness on the kinetics of cluster incorporation in thermally evapd. fatty amine films is analyzed from quartz-crystal microgravimetry (QCM) measurements in terms of a one-dimensional (1-D) Fickian-type diffusion model. Although it is found that 1-D diffusion adequately represents the cluster mass uptake kinetics obsd. using QCM, an interesting film-thickness dependence on the diffusivity was obsd. The nature of the cluster-diffusion curves were quite different for amine films annealed prior to immersion in the colloidal soln. In these cases, the 1-D-diffusion model with a single diffusivity fails, indicating the possible occurrence of addnl. diffusion channels for cluster incorporation. In situ QCM and optical absorption spectroscopy measurements have been made to elucidate the mechanism for cluster diffusion in the thermally evapd. films. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFyjtw%253D%253D&md5=71aededc0f5b3306bf916ddf9993732d
- 93 Henglein, A. Physicochemical Properties of Small Metal Particles in Solution: “Microelectrode” Reactions, Chemisorption, Composite Metal Particles, and the Atom-to-Metal Transition . J. Phys. Chem. 1993 , 97 , 5457 – 5471 , DOI: 10.1021/j100123a004 Google Scholar 93 Physicochemical properties of small metal particles in solution: "microelectrode" reactions, chemisorption, composite metal particles, and the atom-to-metal transition Henglein, Arnim Journal of Physical Chemistry ( 1993 ), 97 ( 21 ), 5457-71 CODEN: JPCHAX ; ISSN: 0022-3654 . The study of nanometer and subnanometer colloidal metal particles in aq. soln. complements the study of small particles in mol. beams, frozen solns., and inorg. clusters. The electronic properties of the metal particles are changed by surface modification, for example by chemisorption of a nucleophilic mol. or by deposition of a 2nd metal. The resulting changes in the chem., photochem., and optical properties are discussed. Methods are described which enable one to store excess electrons or pos. holes on the particles in a controlled manner and to study the accompanying changes in the optical properties. Metal particles carrying excess electrons initiate electrochem. reactions such as the redn. of H2O or the deposition of metals. Concentric bimetallic and trimetallic particles can be synthesized this way. The transition from the atom to the metal can be studied by pulse radiolysis: a known concn. of atom is generated by a pulse and the development of the metal absorption spectrum is then recorded as a function of time as the atoms coalesce to yield larger particles. It is often obsd. that the absorption spectrum of the metal is reached after only a few coalescence steps, i.e. at agglomeration nos. of ∼10. In the case of Ag, 2 magic clusters which are not metallic and having long lifetimes (100 s and 15 min) are obsd. during the coalescence. These clusters have giant absorption bands at wavelengths distinctly shorter than that of the 380-nm plasmon band of metallic Ag particles. The clusters live for hours and days in the presence of polyanions. They have reducing properties and also react eagerly with nucleophilic reagents. They can be fragmented upon illumination and photoemit electrons with quantum yields >0.1. The dependence of the std. redox potential on particle size is also discussed. The atom-to-metal transition manifests itself also in the colloid chem. properties of metal particle (transition from complex formation with anions of oligomeric clusters to double layer formation around larger particles). 80 Refs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVChurc%253D&md5=d44f6b41d652cd508f10fed199c1e443
- 94 Sastry, M. ; Mayya, K. S. ; Bandyopadhyay, K. PH Dependent Changes in the Optical Properties of Carboxylic Acid Derivatized Silver Colloidal Particles . Colloids Surf., A 1997 , 127 , 221 – 228 , DOI: 10.1016/S0927-7757(97)00087-3 Google Scholar 94 pH dependent changes in the optical properties of carboxylic acid derivatized silver colloidal particles Sastry, Murali; Mayya, K. S.; Bandyopadhyay, K. Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 1997 ), 127 ( 1-3 ), 221-228 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier ) The optical properties of Ag colloidal particles derivatized using an arom. bifunctional mol., 4-carboxythiophenol, are presented. The capping mol. forms a thiolate bond with the Ag colloidal particle yielding a carboxylic acid terminal functionality which may then be charged to varying degrees by controlling the Ag hydrosol pH. A progressive red shift together with a damping and broadening of the surface plasmon feature (λmax) of the Ag particles is obsd. as the pH is reduced 10-3. Ag colloidal particles with high surface coverage of the bifunctional mol. showed negligible flocculation with time at high soln. pH indicating good stabilization due to Coulombic repulsive interactions. At low pH, considerable flocculation was obsd. even for high surface coverage due to lack of Coulombic stabilization. A tentative explanation is put forward to explain changes in the optical properties of the colloidal particles due to variation in the pH dependent surface charge of the particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXltFSrs7c%253D&md5=e89fa76e92941d2bf292c0d36a525e27
- 95 Sultana, N. ; Raul, P. K. ; Goswami, D. ; Das, D. ; Islam, S. ; Tyagi, V. ; Das, B. ; Gogoi, H. K. ; Chattopadhyay, P. ; Raju, P. S. Bio-Nanoparticle Assembly: A Potent on-Site Biolarvicidal Agent against Mosquito Vectors . RSC Adv. 2020 , 10 , 9356 – 9368 , DOI: 10.1039/C9RA09972G Google Scholar 95 Bio-nanoparticle assembly: a potent on-site biolarvicidal agent against mosquito vectors Sultana, Nazima; Raul, Prasanta K.; Goswami, Diganta; Das, Dipankar; Islam, Saidul; Tyagi, Varun; Das, Bodhaditya; Gogoi, Hemanta K.; Chattopadhyay, Pronobesh; Raju, Pakalapati S. RSC Advances ( 2020 ), 10 ( 16 ), 9356-9368 CODEN: RSCACL ; ISSN: 2046-2069 . ( Royal Society of Chemistry ) Vector-borne diseases such as malaria, dengue, yellow fever, encephalitis and filariasis are considered serious human health concerns in the field of medical entomol. Controlling the population of mosquito vectors is one of the best strategies for combating such vector-borne diseases. However, the use of synthetic insecticides for longer periods of time increases mosquito resistance to the insecticides. Recently, the search for new environmentally friendly and efficient insecticides has attracted major attention globally. With the evolution of material sciences, researchers have reported the effective control of such diseases using various sustainable resources. The present investigation demonstrates a potent on-site biolarvicidal agent against different mosquito vectors such as Aedes albopictus, Anopheles stephensi and Culex quinquefasciatus. Stable and photo-induced colloidal silver nanoparticles were generated via the surface functionalization of the root ext. of Cyprus rotundas. Characterizations of the nanoparticles were performed using assorted techniques, such as UV-visible spectroscopy, FTIR spectroscopy, DLS and HRTEM. The bioefficacy of the synthesized nanoparticles was investigated against different species of mosquito larvae through the evaluation of their life history trait studies, fecundity and hatchability rate of the treated larvae. Histopathol. and polymerase chain reaction-random amplified polymorphic DNA (RAPD) analyses of the treated larvae were also examd. to establish the cellular damage. The synthesized nanoparticles showed remarkable larvicidal activity against mosquito larvae in a very low concn. range (0.001-1.00) mg L-1. The histopathol. study confirmed that the present nanoparticles could easily enter the cuticle membrane of mosquito larvae and subsequently obliterate their complete intestinal system. Furthermore, RAPD anal. of the treated larvae could assess the damage of the DNA banding pattern. The present work demonstrates a potent biolarvicidal agent using sustainable bioresources of the aq. Cyprus rotundas root ext. The results showed that the synthesized nanoparticles were stable under different physiol. conditions such as temp. and photo-induced oxidn. The effectiveness of these materials against mosquito larvae was quantified at very low dose concns. The present biolarvicidal agent can be considered as an environmentally benign material to control the mosquito vectors with an immense potential for on-site field applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksVWgtro%253D&md5=aefb44759eae426f0b19f2c19714e85e
- 96 Alomar, T. S. ; AlMasoud, N. ; Awad, M. A. ; El-Tohamy, M. F. ; Soliman, D. A. An Eco-Friendly Plant-Mediated Synthesis of Silver Nanoparticles: Characterization, Pharmaceutical and Biomedical Applications . Mater. Chem. Phys. 2020 , 249 , 123007 , DOI: 10.1016/j.matchemphys.2020.123007 Google Scholar 96 An eco-friendly plant-mediated synthesis of silver nanoparticles: Characterization, pharmaceutical and biomedical applications Alomar, Taghrid S.; AlMasoud, Najla; Awad, Manal A.; El-Tohamy, Maha F.; Soliman, Dina A. Materials Chemistry and Physics ( 2020 ), 249 ( ), 123007 CODEN: MCHPDR ; ISSN: 0254-0584 . ( Elsevier B.V. ) The current study focused on green chem. approach to synthesize eco-friendly AgNPs using an aq. ext. of Peganum harmala leaves. The formed AgNPs were characterized using different spectroscopic and microscopic analyses: UV-visible spectrophotometry (UV-Vis), Fluorolog 3 spectrometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier transform IR spectroscopy (FTIR), techniques using a Zetasizer. The resulted nanoparticles were screened for their biomedical and pharmaceutical properties. They investigated for antimicrobial activity against various strains of bacteria and fungi. The synthesized AgNPs showed a higher antibacterial potential against Gram neg. pathogen E. coli with inhibition zone of 65 mm rather than both Gram pos. pathogens S. aureus and B. cereus of inhibition zone 50 mm. Meanwhile, no inhibition zone was obsd. for E. faecalis. Furthermore, the formed AgNPs were applied to enhance the sensitivity and selectivity of the spectrophotometric detn. of the antibiotic Rifaximin in bulk powder or tablet form with a λmax of 340 nm. The proposed spectrophotometric technique for detg. Rifaximin in the presence of silver nanoparticles showed a linear relationship in the concn. ranges of 5-80μg/mL and followed the linear regression equation A = 0.039C-0.166 (r = 0.9997), with low limits of detection and quantification of 1.75 and 5.0μg mL -1, resp. According to the ICH guidelines, the proposed technique was validated. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXmslehtrY%253D&md5=5cdefd726312e68607f350db46eb6ec3
- 97 Varghese Alex, K. ; Tamil Pavai, P. ; Rugmini, R. ; Shiva Prasad, M. ; Kamakshi, K. ; Sekhar, K. C. Green Synthesized Ag Nanoparticles for Bio-Sensing and Photocatalytic Applications . ACS Omega 2020 , 5 , 13123 – 13129 , DOI: 10.1021/acsomega.0c01136 Google Scholar 97 Green Synthesized Ag Nanoparticles for Bio-Sensing and Photocatalytic Applications Varghese Alex, Kevin; Tamil Pavai, Parthiban; Rugmini, Radhasaran; Shiva Prasad, Madavi; Kamakshi, Koppole; Sekhar, Koppole Chandra ACS Omega ( 2020 ), 5 ( 22 ), 13123-13129 CODEN: ACSODF ; ISSN: 2470-1343 . ( American Chemical Society ) In this work, sensing and photocatalytic activities of green synthesized silver nanoparticles (Ag NPs) are investigated. Ag NPs have been synthesized by the redn. of silver nitrate (AgNO3) using different leaf exts. An optimum surface plasmon resonance (SPR) behavior is obtained for neem leaf exts. because of the presence of a high concn. of diterpenoids, as evidenced from gas chromatog. mass spectroscopy results. The underlying mechanism for the formation of Ag NPs is highlighted. The Ag NPs are in spherical shape and exhibit the hexagonal crystal phase and also show a good stability. The biosensing property of the Ag NPs is evaluated using mancozeb (MCZ) agro-fungicide, and the SPR peak position exhibited a linear response with MCZ concn. The sensitivity is found to be 39.1 nm/mM. Further, the photocatalytic activity of Ag NPs is tested using 0.5 mM MCZ soln. as a model under UV-visible illumination. It is obsd. that photocatalytic activity is caused by the formation of reactive oxygen species. Therefore, the green synthesized Ag NPs are potential candidates for biosensing and photocatalytic applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtVSgtL7J&md5=9643816f01b12ca04c9b4dec53682bad
- 98 Parit, S. B. ; Karade, V. C. ; Patil, R. B. ; Pawar, N. v. ; Dhavale, R. P. ; Tawre, M. ; Pardesi, K. ; Jadhav, U. U. ; Dawkar, V. v. ; Tanpure, R. S. ; Kim, J. H. ; Jadhav, J. P. ; Chougale, A. D. Bioinspired Synthesis of Multifunctional Silver Nanoparticles for Enhanced Antimicrobial and Catalytic Applications with Tailored SPR Properties . Mater. Today Chem. 2020 , 17 , 100285 , DOI: 10.1016/j.mtchem.2020.100285 Google Scholar 98 Bioinspired synthesis of multifunctional silver nanoparticles for enhanced antimicrobial and catalytic applications with tailored SPR properties Parit, S. B.; Karade, V. C.; Patil, R. B.; Pawar, N. V.; Dhavale, R. P.; Tawre, M.; Pardesi, K.; Jadhav, U. U.; Dawkar, V. V.; Tanpure, R. S.; Kim, J. H.; Jadhav, J. P.; Chougale, A. D. Materials Today Chemistry ( 2020 ), 17 ( ), 100285 CODEN: MTCAD8 ; ISSN: 2468-5194 . ( Elsevier Ltd. ) In the developing nanotechnol. world, numerous attempts have been made to prep. the nobel metallic nanoparticles (NPs), which can improve their applicability in diverse fields. In the present work, the biosynthesis of silver (Ag) NPs has been successfully achieved through the medicinal plant ext. (PE) of G. resinifera and effectively used for the catalytic and antibacterial applications. The size dependant tuneable surface plasmon resonance (SPR) properties attained through altering precursor concns. The X-ray and selected area diffraction pattern for Ag NPs revealed the high cryst. nature of pure Ag NPs with dominant (111) phase. Accordingly, the dual-band SPR spectrum is situated in the UV-Vis spectra validating the non-spherical shape of Ag NPs. The functional group present on the Ag NPs surface was analyzed by FT-IR confirms the capping and reducing ability of methanolic PE G. resinifera. Further, the mechanism of antimicrobial activity studied using electron microscope showed the morphol. changes with destructed cell walls of E. coli NCIM 2931 and S. aureus NCIM 5021 cells, when they treated with Ag NPs. The Ag NPs were more effective against S. aureus and E. coli with MIC 128μg/mL as compared to P. aeruginosa NCIM 5029 with MIC 256μg/mL. Apart from this, the redn. of toxic org. pollutant 4-NP to 4-AP within 20 min reveals the excellent catalytic activity of Ag NPs with rate const. k = 15.69 s-1. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtFCju7bL&md5=95db3ecc85a7246d73998d7a38eaebe9
- 99 Barchi, J., Jr. Introduction to Comprehensive Glycoscience: The Good, the Better and What’s to Come ; Elsevier Science , 2021 ; pp 1 – 20 . Google Scholar There is no corresponding record for this reference.
- 100 De Roo, J. ; Yazdani, N. ; Drijvers, E. ; Lauria, A. ; Maes, J. ; Owen, J. S. ; van Driessche, I. ; Niederberger, M. ; Wood, V. ; Martins, J. C. ; Infante, I. ; Hens, Z. Probing Solvent-Ligand Interactions in Colloidal Nanocrystals by the NMR Line Broadening . Chem. Mater. 2018 , 30 , 5485 – 5492 , DOI: 10.1021/acs.chemmater.8b02523 Google Scholar 100 Probing Solvent-Ligand Interactions in Colloidal Nanocrystals by the NMR Line Broadening De Roo, Jonathan; Yazdani, Nuri; Drijvers, Emile; Lauria, Alessandro; Maes, Jorick; Owen, Jonathan S.; Van Driessche, Isabel; Niederberger, Markus; Wood, Vanessa; Martins, Jose C.; Infante, Ivan; Hens, Zeger Chemistry of Materials ( 2018 ), 30 ( 15 ), 5485-5492 CODEN: CMATEX ; ISSN: 0897-4756 . ( American Chemical Society ) Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation, and assembly, there is currently no direct method to study this. Here the authors examine the broadening of 1H NMR resonances assocd. with bound ligands and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. The line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent, and the latter results from solvent-ligand interactions. The authors' model is supported by exptl. and theor. evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide, and selenide nanocrystals. The authors' findings thus put forward NMR line-shape anal. as an indispensable tool to form, study, and manipulate nanocolloids. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVeit7rF&md5=3f4ad127ad928d05b4b89d906ee03730
- 101 Fiurasek, P. ; Reven, L. Phosphonic and Sulfonic Acid-Functionalized Gold Nanoparticles: A Solid-State NMR Study . Langmuir 2007 , 23 , 2857 – 2866 , DOI: 10.1021/la0629781 Google Scholar 101 Phosphonic and Sulfonic Acid-Functionalized Gold Nanoparticles: A Solid-State NMR Study Fiurasek, Petr; Reven, Linda Langmuir ( 2007 ), 23 ( 5 ), 2857-2866 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Gold nanoparticles capped with 11-mercaptoundecanylphosphonic acid (MUP) and sodium 10-mercaptodecanesulfonic acid (MDS) were characterized by a range of techniques which included solid-state 31P and 13C NMR spectroscopies. Despite similar core sizes and alkyl chain lengths, the conformational and dynamic properties of the capping ligands are very different for the two types of nanoparticles. Whereas MDS produces disordered monolayers on planar gold surfaces, the MDS-capped nanoparticles show a high degree of chain order with the onset of reversible chain disordering occurring just above room temp. The alkyl chains of MUP adsorbed on the gold nanoparticles are more ordered and motionally restricted than the unbound solid surfactant due to strong intramonolayer and interparticle hydrogen bonds. This conformational order is thermally stable, and disordering only occurs upon decompn. and desorption of MUP from the gold core. Solid-state 31P NMR is a sensitive probe of the interactions of the PO3H2 terminal groups. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXktF2luw%253D%253D&md5=4b26e299d334dad3b4ed31e2cf0b6048
- 102 Sadasivan, S. ; Khushalani, D. ; Mann, S. Synthesis and Shape Modification of Organo-Functionalised Silica Nanoparticles with Ordered Mesostructured Interiors . J. Mater. Chem. 2003 , 13 , 1023 – 1029 , DOI: 10.1039/b300851g Google Scholar 102 Synthesis and shape modification of organo-functionalized silica nanoparticles with ordered mesostructured interiors Sadasivan, Sajanikumari; Khushalani, Deepa; Mann, Stephen Journal of Materials Chemistry ( 2003 ), 13 ( 5 ), 1023-1029 CODEN: JMACEP ; ISSN: 0959-9428 . ( Royal Society of Chemistry ) Organo-functionalized MCM-41 nanoparticles have been prepd. by a diln./neutralisztion method involving the surfactant-templated co-condensation of 3-aminopropyltriethoxysilane, allyltriethoxysilane or 3-mercaptopropyltriethoxysilane with tetraethoxysilane under alk. conditions. The presence of covalently coupled org. groups within the hexagonally ordered silica mesophase was confirmed by solid-state 13C and 29Si MAS NMR spectroscopy. TEM studies show that amine- and allyl-functionalized nanoparticles are single-domain oblate ellipsoidal crystals, in which the cylindrical micelles are aligned parallel to the morphol. minor axis. In contrast, the thiol-functionalized nanoparticles were synthesized in the form of nanofilaments elongated specifically along the channel direction of the MCM-41 hexagonal mesostructure. A mechanism is proposed in which changes in the nanoparticle morphol. are attributed predominantly to an increase in surface charge assocd. with the anionic mercaptopropyl groups that inhibits the side-on attachment of silica-surfactant micelles to partially ordered primary nanoclusters. In contrast, nanoparticles with neutral side chains, such as amino and allyl moieties, as well as unfunctionalized MCM-41, develop by side-on attachment to radially arranged defect sites of a modulated hexagonal mesophase assocd. with the oblate ellipsoidal morphol. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtVCntLY%253D&md5=b79a42eccccbe2c22a25a31258646890
- 103 Marbella, L. E. ; Millstone, J. E. NMR Techniques for Noble Metal Nanoparticles . Chem. Mater. 2015 , 27 , 2721 – 2739 , DOI: 10.1021/cm504809c Google Scholar 103 NMR Techniques for Noble Metal Nanoparticles Marbella, Lauren E.; Millstone, Jill E. Chemistry of Materials ( 2015 ), 27 ( 8 ), 2721-2739 CODEN: CMATEX ; ISSN: 0897-4756 . ( American Chemical Society ) Soln. phase noble metal nanoparticle growth reactions are comprised of deceptively simple steps. Anal. methods with high chem., spatial, and temporal resoln. are crucial to understanding these reactions and subsequent nanoparticle properties. However, approaches for the characterization of solid inorg. materials and soln. phase mol. species are often disparate. One powerful technique to address this gap is NMR spectroscopy, which can facilitate routine, direct, mol.-scale anal. of nanoparticle formation and morphol. in situ, in both the soln. and the solid phase. A growing body of work indicates that NMR analyses should yield an exciting complement to the existing canon of routine nanoparticle characterization methods such as electron microscopy and optical absorption spectroscopy. Recent developments in the application of NMR techniques to the study of noble metal nanoparticle growth, surface chem., and phys. properties are discussed. Specifically, the authors describe the unique capabilities of NMR in resolving hard-soft matter interfaces with both high chem. and high spatial resoln. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkt1Oisbs%253D&md5=3d84a29057d3d85506d74308e1a6f189
- 104 Li, Y. ; Jin, R. Seeing Ligands on Nanoclusters and in Their Assemblies by X-Ray Crystallography: Atomically Precise Nanochemistry and Beyond . J. Am. Chem. Soc. 2020 , 142 , 13627 – 13644 , DOI: 10.1021/jacs.0c05866 Google Scholar 104 Seeing Ligands on Nanoclusters and in Their Assemblies by X-ray Crystallography: Atomically Precise Nanochemistry and Beyond Li, Yingwei; Jin, Rongchao Journal of the American Chemical Society ( 2020 ), 142 ( 32 ), 13627-13644 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A review. Ligands are of tremendous importance for colloidal nanoparticles (NPs) in terms of surface protection, size and shape control, tailoring properties, self-assembly, and applications. However, it is very challenging to obtain unambiguous information on the ligands and their interactions and patterning on NPs. The recent advent of atomically precise nanochem. has opened new horizons. One can now see ligands with at. resoln. and understand their behavior on the surface of ultrasmall NPs (1-3 nm) and also in their assemblies. Such atomically precise NPs (or nanoclusters, NCs) bridge up with conventional NPs by providing unprecedented opportunities to reveal the specific patterns formed by intra- and inter-particle ligand interactions. In this Perspective, we first discuss how to achieve atomically precise NCs and det. their total structures. Then, we highlight the intra-particle ligand interactions (i.e., the ligand shell), including the various patterns formed on the NCs, the ligand patterning modes on facets and edges, and some aesthetic patterns assembled by ligands that are akin to biomol. organization. The inter-particle ligand interactions and their roles in directing the self-assembly of NCs into coherent superlattices are also discussed, which provides a deep understanding of assembly mechanisms, with the insights from atomically precise NCs hinting for the assembly of conventional NPs. Overall, the success in achieving atomically precise NCs is expected to bring new opportunities to fields beyond nanochem., esp. to materials design, engineering, and applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlyjsr%252FN&md5=c3b785e350fec39a04a943427415f730
- 105 Sakthivel, N. A. ; Shabaninezhad, M. ; Sementa, L. ; Yoon, B. ; Stener, M. ; Whetten, R. L. ; Ramakrishna, G. ; Fortunelli, A. ; Landman, U. ; Dass, A. The Missing Link: Au191(SPh- TBu)66Janus Nanoparticle with Molecular and Bulk-Metal-like Properties . J. Am. Chem. Soc. 2020 , 142 , 15799 – 15814 , DOI: 10.1021/jacs.0c05685 Google Scholar 105 The Missing Link: Au191(SPh-tBu)66 Janus Nanoparticle with Molecular and Bulk-Metal-like Properties Sakthivel, Naga Arjun; Shabaninezhad, Masoud; Sementa, Luca; Yoon, Bokwon; Stener, Mauro; Whetten, Robert L.; Ramakrishna, Guda; Fortunelli, Alessandro; Landman, Uzi; Dass, Amala Journal of the American Chemical Society ( 2020 ), 142 ( 37 ), 15799-15814 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) Understanding the evolution of the structure and properties in metals from mol.-like to bulk-like was a long sought fundamental question in science, since Faraday's 1857 work. The authors report the discovery of a Janus nanomol., Au191(SPh-tBu)66 having both mol. and metallic characteristics, explored crystallog. and optically and modeled theor. Au191 has an anisotropic, singly twinned structure with an Au155 core protected by a ligand shell made of 24 monomeric [-S-Au-S-] and 6 dimeric [-S-Au-S-Au-S-] staples. The Au155 core is composed of an 89-atom inner core and 66 surface atoms, arranged as [Au3@Au23@Au63]@Au66 concentric shells of atoms. The inner core has a monotwinned/stacking-faulted fcc. structure. Structural evolution in metal nanoparticles was known to progress from multiply twinned, icosahedral, structures in smaller mol. sizes to untwinned bulk-like fcc. monocryst. nanostructures in larger nanoparticles. The monotwinned inner core structure of the ligand capped Au191 nanomol. provides the crit. missing link, and bridges the size-evolution gap between the mol. multiple-twinning regime and the bulk-metal-like particles with untwinned fcc. structure. The Janus nature of the nanoparticle is demonstrated by its optical and electronic properties, with metal-like electron-phonon relaxation and mol.-like long-lived excited states. First-principles theor. explorations of the electronic structure uncovered electronic stabilization through the opening of a shell-closing gap at the top of the occupied manifold of the delocalized electronic superatom spectrum of the inner core. The electronic stabilization together with the inner core geometric stability and the optimally stapled ligand-capping anchor and secure the stability of the entire nanomol. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhslant7vP&md5=a2178d30533b0730e3b1a9e93b6066ab
- 106 Sapsford, K. E. ; Tyner, K. M. ; Dair, B. J. ; Deschamps, J. R. ; Medintz, I. L. Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques . Anal. Chem. 2011 , 83 , 4453 – 4488 , DOI: 10.1021/ac200853a Google Scholar 106 Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques Sapsford, Kim E.; Tyner, Katherine M.; Dair, Benita J.; Deschamps, Jeffrey R.; Medintz, Igor L. Analytical Chemistry (Washington, DC, United States) ( 2011 ), 83 ( 12 ), 4453-4488 CODEN: ANCHAM ; ISSN: 0003-2700 . ( American Chemical Society ) A review with major sections on purifn., characterization (sepn. techniques, scattering techniques, microscopy, and spectroscopy), modeling, and emerging technologies and instrumentation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXls1ekt7w%253D&md5=0a45ab29e7a9e9003899247720acd8e5
- 107 Cao, G. ; Wang, Y. Characterization and Properties of Nanomaterials . Nanostructures and Nanomaterials 2011 , 433 – 508 , DOI: 10.1142/9789814340571_0008 Google Scholar There is no corresponding record for this reference.
- 108 Chapman, H. N. ; Fromme, P. ; Barty, A. ; White, T. A. ; Kirian, R. A. ; Aquila, A. ; Hunter, M. S. ; Schulz, J. ; Deponte, D. P. ; Weierstall, U. Femtosecond X-Ray Protein Nanocrystallography . Nature 2011 , 470 , 73 – 77 , DOI: 10.1038/nature09750 Google Scholar 108 Femtosecond X-ray protein nanocrystallography Chapman, Henry N.; Fromme, Petra; Barty, Anton; White, Thomas A.; Kirian, Richard A.; Aquila, Andrew; Hunter, Mark S.; Schulz, Joachim; DePonte, Daniel P.; Weierstall, Uwe; Doak, R. Bruce; Maia, Filipe R. N. C.; Martin, Andrew V.; Schlichting, Ilme; Lomb, Lukas; Coppola, Nicola; Shoeman, Robert L.; Epp, Sascha W.; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Holl, Peter; Liang, Mengning; Barthelmess, Miriam; Caleman, Carl; Boutet, Sebastien; Bogan, Michael J.; Krzywinski, Jacek; Bostedt, Christoph; Bajt, Sasa; Gumprecht, Lars; Rudek, Benedikt; Erk, Benjamin; Schmidt, Carlo; Hoemke, Andre; Reich, Christian; Pietschner, Daniel; Strueder, Lothar; Hauser, Guenter; Gorke, Hubert; Ullrich, Joachim; Herrmann, Sven; Schaller, Gerhard; Schopper, Florian; Soltau, Heike; Kuehnel, Kai-Uwe; Messerschmidt, Marc; Bozek, John D.; Hau-Riege, Stefan P.; Frank, Matthias; Hampton, Christina Y.; Sierra, Raymond G.; Starodub, Dmitri; Williams, Garth J.; Hajdu, Janos; Timneanu, Nicusor; Seibert, M. Marvin; Andreasson, Jakob; Rocker, Andrea; Joensson, Olof; Svenda, Martin; Stern, Stephan; Nass, Karol; Andritschke, Robert; Schroeter, Claus-Dieter; Krasniqi, Faton; Bott, Mario; Schmidt, Kevin E.; Wang, Xiaoyu; Grotjohann, Ingo; Holton, James M.; Barends, Thomas R. M.; Neutze, Richard; Marchesini, Stefano; Fromme, Raimund; Schorb, Sebastian; Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Andersson, Inger; Hirsemann, Helmut; Potdevin, Guillaume; Graafsma, Heinz; Nilsson, Bjoern; Spence, John C. H. Nature (London, United Kingdom) ( 2011 ), 470 ( 7332 ), 73-77 CODEN: NATUAS ; ISSN: 0028-0836 . ( Nature Publishing Group ) X-ray crystallog. provides the vast majority of macromol. structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been detd. despite their importance in all living cells. Here we present a method for structure detn. where single-crystal X-ray diffraction snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (∼200 nm to 2 μm in size). We mitigate the problem of radiation damage in crystallog. by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure detn. of macromols. that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVyguro%253D&md5=0fc5b6f7c78cf49893dc15704db706a7
- 109 Majeed Khan, M. A. ; Kumar, S. ; Ahamed, M. ; Alrokayan, S. A. ; AlSalhi, M. S. Structural and Thermal Studies of Silver Nanoparticles and Electrical Transport Study of Their Thin Films . Nanoscale Res. Lett. 2011 , 6 , 1 – 8 , DOI: 10.1186/1556-276X-6-434 Google Scholar There is no corresponding record for this reference.
- 110 Upadhyay, S. ; Parekh, K. ; Pandey, B. Influence of Crystallite Size on the Magnetic Properties of Fe3O4 Nanoparticles . J. Alloys Compd. 2016 , 678 , 478 – 485 , DOI: 10.1016/j.jallcom.2016.03.279 Google Scholar 110 Influence of crystallite size on the magnetic properties of Fe3O4 nanoparticles Upadhyay, Sneha; Parekh, Kinnari; Pandey, Brajesh Journal of Alloys and Compounds ( 2016 ), 678 ( ), 478-485 CODEN: JALCEU ; ISSN: 0925-8388 . ( Elsevier B.V. ) Structural and magnetic properties of chem. synthesized magnetite nanoparticles have been studied using X-ray diffraction, Transmission Electron Microscopy and Vibrating Sample Magnetometer. Magnetically the synthesized nanoparticles are ranging from superparamagnetic to multi domain state. Av. crystallite size of the synthesized magnetite nanoparticles were detd. using X-ray line broadening and are found to be in the range of 9-53 nm. On the other hand, the TEM images show that the size is ranging between 7.9 and 200 nm with the transition from spherical superparamagnetic particles to faceted cubic multi domain particles. Magnetic parameters of the samples show a strong dependence on av. crystallite size. The ratio of coercive field at 20 K to that at 300 K (Hc (20 K)/Hc (300 K)) increased sharply with decrease in crystallite size. A crit. crystallite diam. of order 36 nm may be inferred as boundary between single domain to multi domain transition. Zero-field-cooled (ZFC) and field-cooled (FC) measurements at 10 Oe field validate the same for smallest and largest size samples, confirming that the anisotropy energy is greater than thermal energy up to 300 K temp. For 9 nm sample broad ZFC curve with overlapping of FC curve is obsd. just at 300 K, indicating the effect of strong dipolar field in superparamagnetic system. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmtVOlsL8%253D&md5=e98f4e353e1962bbcc19d27aa62c50ed
- 111 Fissan, H. ; Ristig, S. ; Kaminski, H. ; Asbach, C. ; Epple, M. Comparison of Different Characterization Methods for Nanoparticle Dispersions before and after Aerosolization . Anal. Methods 2014 , 6 , 7324 – 7334 , DOI: 10.1039/C4AY01203H Google Scholar 111 Comparison of different characterization methods for nanoparticle dispersions before and after aerosolization Fissan, Heinz; Ristig, Simon; Kaminski, Heinz; Asbach, Christof; Epple, Matthias Analytical Methods ( 2014 ), 6 ( 18 ), 7324-7334 CODEN: AMNEGX ; ISSN: 1759-9679 . ( Royal Society of Chemistry ) A well-known and accepted aerosol measurement technique, the scanning mobility particle sizer (SMPS), is applied to characterize colloidally dispersed nanoparticles. To achieve a transfer from dispersed particles to aerosolized particles, a newly developed nebulizer (N) is used that, unlike commonly used atomizers, produces significantly smaller droplets and therefore reduces the problem of the formation of residual particles. The capabilities of this new instrument combination (N + SMPS) for the anal. of dispersions were investigated, using three different dispersions, i.e. gold-PVP nanoparticles (∼20 nm), silver-PVP nanoparticles (∼70 nm) and their 1 : 1 (m : m) mixt. The results are compared to SEM measurements and two frequently applied techniques for characterizing colloidal systems: Dynamic light scattering (DLS) and anal. disk centrifugation (ADC). The differences, advantages and disadvantages of each method are discussed, esp. with respect to the size resoln. of the techniques and their ability to distinguish the particle sizes of the mixed dispersion. While DLS is, as expected, unable to resolve the binary dispersion, SEM, ADC and SMPS are able to give quant. information on the two particle sizes. However, while the high-resolving ADC is limited due to the dependency on a predefined d. of the investigated system, the transfer of dispersed particles into an aerosol and subsequent anal. with SMPS are an adequate way to characterize binary systems, independent of the d. of concerned particles, but matching the high resoln. of the ADC. We show that it is possible to use the well-established aerosol measurement technique (N + SMPS) in colloid science with all its advantages concerning size resoln. and accuracy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFOks7nO&md5=164ae5103811776a21db0a50f631f2c3
- 112 Surface Analysis Methods in Materials Science . In Springer Series in Surface Sciences ; O’Connor, D. J. , Sexton, B. A. , St, R. , Smart, C. , Eds.; Springer Berlin Heidelberg , 2003 . Google Scholar There is no corresponding record for this reference.
- 113 Veisi, H. ; Dadres, N. ; Mohammadi, P. ; Hemmati, S. Green Synthesis of Silver Nanoparticles Based on Oil-Water Interface Method with Essential Oil of Orange Peel and Its Application as Nanocatalyst for A3 Coupling . Materials Science and Engineering: C 2019 , 105 , 110031 , DOI: 10.1016/j.msec.2019.110031 Google Scholar 113 Green synthesis of silver nanoparticles based on oil-water interface method with essential oil of orange peel and its application as nanocatalyst for A3 coupling Veisi, Hojat; Dadres, Nahid; Mohammadi, Pourya; Hemmati, Saba Materials Science & Engineering, C: Materials for Biological Applications ( 2019 ), 105 ( ), 110031 CODEN: MSCEEE ; ISSN: 0928-4931 . ( Elsevier B.V. ) Silver (Ag) nanoparticles (NPs) were prepd. through a biol. procedure where the essential oils of orange peel were used as a capper and reducing agent. Characterization of these Ag/EOs orange NPs was carried out using X-ray diffraction, Fourier transformed IR spectroscopy, field emission SEM, energy dispersive X-ray spectroscopy, transmission electron microscopy, UV-visible spectroscopy and thermogravimetric anal. (TGA). These NPs were utilized as an effective heterogeneous nanocatalyst for the three-component A3 coupling reaction of secondary amines, aldehydes and terminal alkynes for the synthesis of propargylamines RC≡CCH(R1)(NR2R3) [R = n-hexyl, Ph; R1 = n-Pr, Ph, 2-thienyl, etc.; R2 = R3 = Et, Bn; R2R3 = (CH2)4, (CH2)5, (CH2)2O(CH2)2]. Different ranges with high performance were achieved for propargylamines. Moreover, the isolation and recovery of Ag/EOs orange NPs was very easy, efficient and cost effective. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFWlsbbL&md5=1cb6409048149d381b81de2ba250b6e3
- 114 Yoo, J. ; So, H. ; Yang, M. H. ; Lee, K. J. Effect of Chloride Ion on Synthesis of Silver Nanoparticle Using Retrieved Silver Chloride as a Precursor from the Electronic Scrap . Appl. Surf. Sci. 2019 , 475 , 781 – 784 , DOI: 10.1016/j.apsusc.2019.01.032 Google Scholar 114 Effect of chloride ion on synthesis of silver nanoparticle using retrieved silver chloride as a precursor from the electronic scrap Yoo, Juyeon; So, Hyeongsub; Yang, Min-Ho; Lee, Kun-Jae Applied Surface Science ( 2019 ), 475 ( ), 781-784 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) Retrieving silver from available resources, esp. the electronic scraps (E-scraps), is becoming more important due to increasing demand for electronic industry and rapid growth in disposal problems of the E-scraps. Although chem. leaching has been extensively employed to retrieve the silver, the purity issue still remains. In this work, the silver nanoparticles (Ag NPs) with high purity are synthesized using the retrieved silver chloride (AgCl) from the E-scraps via chem. leaching and selective pptn. These particles show an av. diam. of 68 nm and narrow size distribution. The effect of Cl- ions on particles synthesis are also investigated, resulting in variation in shape and size of particles due to selective etching and slow growth rate. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXpvF2jsg%253D%253D&md5=d697253d58440512ce985fa2ae98b494
- 115 Choma, J. ; Jamioła, D. ; Ludwinowicz, J. ; Jaroniec, M. Deposition of Silver Nanoparticles on Silica Spheres and Rods . Colloids Surf., A 2012 , 411 , 74 – 79 , DOI: 10.1016/j.colsurfa.2012.07.004 Google Scholar 115 Deposition of silver nanoparticles on silica spheres and rods Choma, Jerzy; Jamiola, Dominik; Ludwinowicz, Jowita; Jaroniec, Mietek Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2012 ), 411 ( ), 74-79 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Spherical and rod-like silica particles were used as cores to deposit shells of silver nanoparticles. Prior silver deposition the siliceous cores were modified with 3-aminopropyltrimetoxysilane to facilitate Ag deposition on the surface of silica particles. The process of Ag deposition was carried out in two consecutive steps: first, silver nanoparticles were deposited on the silica cores from silver nitrate soln. in the presence of ammonia and Sn2+ ions. Next, further deposition of silver was achieved by reducing silver cations with formaldehyde. This process led to the formation of a densely packed silver layer that consisted of non-uniform silver nanoparticles (size from several to about 100 nm), on the surface of spherical and rod-like siliceous cores. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOmsb7F&md5=39360fb93184918c789fc1e3188dd3a6
- 116 Liu, K. G. ; Abbasi, A. R. ; Azadbakht, A. ; Hu, M. L. ; Morsali, A. Deposition of Silver Nanoparticles on Polyester Fiber under Ultrasound Irradiations . Ultrason. Sonochem. 2017 , 34 , 13 – 18 , DOI: 10.1016/j.ultsonch.2016.04.006 Google Scholar 116 Deposition of silver nanoparticles on polyester fiber under ultrasound irradiations Liu, Kuan-Guan; Abbasi, Amir Reza; Azadbakht, Azadeh; Hu, Mao-Lin; Morsali, Ali Ultrasonics Sonochemistry ( 2017 ), 34 ( ), 13-18 CODEN: ULSOER ; ISSN: 1350-4177 . ( Elsevier B.V. ) The polyester fiber contg. Ag nanoparticles was prepd. through the chem. redn. under ultrasound irradn. Influences of redn. reagents on the morphol. properties of Ag nanoparticles@polyester fiber were studied. The sizes of metallic nanoparticles vary significantly with the types of redn. reagents used in the synthesis. A strong redn. reaction promotes a fast reaction rate and favors the formation of smaller nanoparticle. A weak redn. reagent induces a slow reaction rate and favors relatively larger particles. The products were investigated by means of SEM and X-ray powder diffraction (XRPD). >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XotV2gtL8%253D&md5=5b23a9f177fafc7601055d5a72551a6d
- 117 Shahid-ul-Islam ; Butola, B. S. ; Verma, D. Facile Synthesis of Chitosan-Silver Nanoparticles onto Linen for Antibacterial Activity and Free-Radical Scavenging Textiles . Int. J. Bio. Macromol. 2019 , 133 , 1134 – 1141 , DOI: 10.1016/j.ijbiomac.2019.04.186 Google Scholar 117 Facile synthesis of chitosan-silver nanoparticles onto linen for antibacterial activity and free-radical scavenging textiles Shahid-ul-Islam; Butola, B. S.; Verma, Deepali International Journal of Biological Macromolecules ( 2019 ), 133 ( ), 1134-1141 CODEN: IJBMDR ; ISSN: 0141-8130 . ( Elsevier B.V. ) In this work, we present a straightforward and rapid green chem.-based method to fabricate chitosan-based silver nanoparticles onto linen fabric in the presence of pineapple crown ext. biomols. such as sucrose, fructose and glucose. The resultant nanoparticles were studied by UV-vis, TEM, EDX, and their coating onto linen was supported by results from SEM, EDX with mapping images, FTIR spectroscopy and TGA technique. This one step process yields spherical particles that are well dispersed and non-aggregated. Using chitosan polysaccharide, the coloring, antibacterial and radical scavenging activity of Ag nanoparticles (NPs) could be transferred to the linen fabric surface. Chitosan not only favors coating and stabilization of the silver ions, but synergistically with silver nanoparticles also exhibited strong antibacterial and antioxidant effects onto linen surface. The coloring properties of coated linen fabrics were measured in terms of CIELa*b* values using reflectance spectroscopy. The coated linen was also screened for their antibacterial activity against E. coli and S. aureus, while as antioxidant activity was investigated photometrically by DPPH assay. The results demonstrate that chitosan-silver nanoparticles can be used as safer and greener alternative to chem. functional agents currently being practiced. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptVSktrc%253D&md5=09a90eb05c053f115df84b6cc69acf34
- 118 Yu, X. Y. ; Arey, B. ; Chatterjee, S. ; Chun, J. Improving in Situ Liquid SEM Imaging of Particles . Surf. Interface Anal. 2019 , 51 , 1325 – 1331 , DOI: 10.1002/sia.6700 Google Scholar 118 Improving in situ liquid SEM imaging of particles Yu, Xiao-Ying; Arey, Bruce; Chatterjee, Sayandev; Chun, Jaehun Surface and Interface Analysis ( 2019 ), 51 ( 13 ), 1325-1331 CODEN: SIANDQ ; ISSN: 0142-2421 . ( John Wiley & Sons Ltd. ) This work presents in situ imaging of synthesized boehmite (γ-AlOOH) particles ranging from 20 to 100 nm, suspended in liq., in a vacuum compatible microfluidic sample holder using a SEM under the high vacuum mode and highlights the advantage of in situ liq. imaging of colloids. Nanometer-sized boehmite particles in high-level radioactive wastes at the Hanford site are known to be difficult to dissolve and cause rheol. problems for processing in the nuclear waste treatment plant. Therefore, it is important to characterize boehmite particles and understand how they form aggregates in the liq. state. Several tech. advancements are made to optimize in situ liq. SEM chem. imaging resulting in the improved ability to obtain secondary electron (SE), backscattered electron (BSE) images, and energy dispersive X-ray spectroscopy (EDX) spectra. Moreover, our results show mixed particles could be studied and identified based on the particle shape and elemental compn. using in situ SEM imaging and EDX. Thus, we provide a new and improved approach to observe the evolution of particle dispersion and stability in liq. under conditions similar to those in the waste tank. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs12gsL7J&md5=e15f260069fe826152bc1ac12e43ccee
- 119 Sekine, R. ; Moore, K. L. ; Matzke, M. ; Vallotton, P. ; Jiang, H. ; Hughes, G. M. ; Kirby, J. K. ; Donner, E. ; Grovenor, C. R. M. ; Svendsen, C. ; Lombi, E. Complementary Imaging of Silver Nanoparticle Interactions with Green Algae: Dark-Field Microscopy, Electron Microscopy, and Nanoscale Secondary Ion Mass Spectrometry . ACS Nano 2017 , 11 , 10894 – 10902 , DOI: 10.1021/acsnano.7b04556 Google Scholar 119 Complementary Imaging of Silver Nanoparticle Interactions with Green Algae: Dark-Field Microscopy, Electron Microscopy, and Nanoscale Secondary Ion Mass Spectrometry Sekine, Ryo; Moore, Katie L.; Matzke, Marianne; Vallotton, Pascal; Jiang, Haibo; Hughes, Gareth M.; Kirby, Jason K.; Donner, Erica; Grovenor, Chris R. M.; Svendsen, Claus; Lombi, Enzo ACS Nano ( 2017 ), 11 ( 11 ), 10894-10902 CODEN: ANCAC3 ; ISSN: 1936-0851 . ( American Chemical Society ) Increasing consumer use of engineered nanomaterials has led to significantly increased efforts to understand their potential impact on the environment and living organisms. Currently, no individual technique can provide all the necessary information such as their size, distribution and chem. in complex biol. systems. Consequently, there is a need to develop complementary instrumental imaging approaches that provide enhanced understanding of these "bio-nano" interactions to overcome the limitations of individual techniques. Here we used a multimodal imaging approach incorporating dark-field light microscopy, high resoln. electron microscopy and nanoscale secondary ion mass spectrometry (NanoSIMS). The aim was to gain insight into the bio-nano interactions of surface functionalised silver nanoparticles (Ag-NPs) with the green algae Raphidocelis subcapitata, by combining the fidelity, spatial resoln., and elemental identification offered by the three techniques, resp. Each technique revealed that Ag-NPs interact with the green algae with a dependence on the size (10 nm vs. 60 nm) and surface functionality (tannic acid and branched polyethyleneimine, bPEI) of the NPs. Dark-field light microscopy revealed the presence of strong light-scatterers on the algal cell surface, and SEM imaging confirmed their nanoparticulate nature and localization at nanoscale resoln. NanoSIMS imaging confirmed their chem. identity as Ag, with the majority of signal concd. at the cell surface. Furthermore, SEM and NanoSIMS provided evidence of 10 nm bPEI Ag-NP internalization at higher concns. (40 μg/L), correlating with the highest toxicity obsd. from these NPs. This multimodal approach thus demonstrated an effective approach to complement dose-response studies in nano-(eco)-toxicol. investigations. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhslSit7rL&md5=4a4808e8ed35bcc4092f59da8cc9ba49
- 120 Guehrs, E. ; Schneider, M. ; Günther, C. M. ; Hessing, P. ; Heitz, K. ; Wittke, D. ; López-Serrano Oliver, A. ; Jakubowski, N. ; Plendl, J. ; Eisebitt, S. ; Haase, A. Quantification of Silver Nanoparticle Uptake and Distribution within Individual Human Macrophages by FIB/SEM Slice and View . J. Nanobiotechnol. 2017 , 15 , 1 – 11 , DOI: 10.1186/s12951-017-0255-8 Google Scholar There is no corresponding record for this reference.
- 121 Stabentheiner, E. ; Zankel, A. ; Pölt, P. Environmental Scanning Electron Microscopy (ESEM)─a Versatile Tool in Studying Plants . Protoplasma 2010 , 246 ( 1 ), 89 – 99 , DOI: 10.1007/s00709-010-0155-3 Google Scholar 121 Environmental scanning electron microscopy (ESEM)--a versatile tool in studying plants Stabentheiner Edith; Zankel Armin; Polt Peter Protoplasma ( 2010 ), 246 ( 1-4 ), 89-99 ISSN: . Environmental scanning electron microscopy (ESEM) enables the investigation of hydrated and uncoated plant samples and the in situ observation of dynamic processes. Water vapor in the microscope chamber takes part in secondary electron detection and charge prevention. Two ESEM modes are available and offer a broad spectrum of applications. The environmental or wet mode prevents sample dehydration by the combination of sample cooling (5°C) and a vapor pressure of 4-6 Torr. In the low vacuum mode, the maximum chamber pressure is limited to 1 Torr (corresponding to about 5% relative humidity in the chamber) and allows the simultaneous use of a backscattered electron detector for imaging material contrast. A selection of characteristic plant samples and various applications are presented as a guide to ESEM for plant scientists. Leaf surfaces, trichomes, epicuticular waxes, and inorganic surface layers represent samples being comparatively resistant to dehydration, whereas callus cells and stigmatic tissue are examples for dehydration- and beam-sensitive samples. The potential of investigating dynamic processes in situ is demonstrated by studying anther opening, by tensile testing of leaves, and by performing hydration/dehydration experiments by changing the vapor pressure. Additionally, automated block-face imaging and serial sectioning using in situ ultramicrotomy is presented. The strengths and weaknesses of ESEM are discussed and it is shown that ESEM is a versatile tool in plant science. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3cflsVOksA%253D%253D&md5=bfa17a0249df8096107d333a837d6e6a
- 122 Agressott, E. V. H. ; Blätte, D. ; Cunha, F. A. ; Noronha, V. T. ; Ciesielski, R. ; Hartschuh, A. ; Paula, A. J. de ; Fechine, P. B. A. ; Souza Filho, A. G. ; Paschoal, A. R. Vibrational Spectroscopy and Morphological Studies on Protein-Capped Biosynthesized Silver Nanoparticles . ACS Omega 2020 , 5 , 386 – 393 , DOI: 10.1021/acsomega.9b02867 Google Scholar 122 Vibrational Spectroscopy and Morphological Studies on Protein-Capped Biosynthesized Silver Nanoparticles Agressott, Enzo Victorino Hernandez; Blatte, Dominic; Cunha, Francisco Afranio; Noronha, Victor T.; Ciesielski, Richard; Hartschuh, Achim; de Paula, Amauri Jardim; Fechine, Pierre Basilio Almeida; Souza Filho, Antonio Gomes; Paschoal, Alexandre Rocha ACS Omega ( 2020 ), 5 ( 1 ), 386-393 CODEN: ACSODF ; ISSN: 2470-1343 . ( American Chemical Society ) Silver nanoparticles (AgNPs) have a large no. of applications in technol. and phys. and biol. sciences. These nanomaterials can be synthesized by chem. and biol. methods. The biol. synthesis using fungi represents a green approach for nanomaterial prodn. that has the advantage of biocompatibility. This work studies silver nanoparticles (AgNPs) produced by fungi Rhodotorula glutinis and Rhodotorula mucilaginosa found in ordinary soil of the Universidade Federal do Cear´a campus (Brazil). The biosynthesized AgNPs have a protein-capping layer involving a metallic Ag core. The focus of this paper is to investigate the size and structure of the capping layer, how it interacts with the Ag core, and how sensitive the system (core + protein) is to visible light illumination. For this, we employed SEM, AFM, photoluminescence spectroscopy, SERS, and dark-field spectroscopy. The AgNPs were isolated, and SEM measurements showed the av. size diam. between 58 nm for R. glutinis and 30 nm for R. mucilaginosa. These values are in agreement with the AFM measurements, which also provided the av. size diam. of 85 nm for R. glutinis and 56 nm for R. mucilaginosa as well as addnl. information about the av. size of the protein-capping layers, whose found values were 24 and 21 nm for R. mucilaginosa and R. glutinis nanoparticles, resp. The protein-capping layer structure seemed to be easily disturbed, and the SERS spectra were unstable. It was possible to identify Raman peaks that might be related to α-helix, β-sheet, and protein mixed structures. Finally, dark-field microscopy showed that the silver cores are very stable, but some are affected by the laser energy due to heating or melting. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsVCjsA%253D%253D&md5=611e45b2c8f2cfe57914563f3f794e2a
- 123 Williams, D. B. ; Carter, C. B. The Transmission Electron Microscope . In Transmission Electron Microscopy ; Springer US , 1996 ; pp 3 – 17 . Google Scholar There is no corresponding record for this reference.
- 124 Reymond-Laruinaz, S. ; Saviot, L. ; Potin, V. ; Marco de Lucas, M. C. Protein–Nanoparticle Interaction in Bioconjugated Silver Nanoparticles: A Transmission Electron Microscopy and Surface Enhanced Raman Spectroscopy Study . Appl. Surf. Sci. 2016 , 389 , 17 – 24 , DOI: 10.1016/j.apsusc.2016.07.082 Google Scholar 124 Protein-nanoparticle interaction in bioconjugated silver nanoparticles: A transmission electron microscopy and surface enhanced Raman spectroscopy study Reymond-Laruinaz, Sebastien; Saviot, Lucien; Potin, Valerie; Marco de Lucas, Maria del Carmen Applied Surface Science ( 2016 ), 389 ( ), 17-24 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) Understanding the mechanisms of interaction between proteins and noble metal nanoparticles (NPs) is crucial to extend the use of NPs in biol. applications and nanomedicine. We report the synthesis of Ag-NPs:protein bioconjugates synthesized in total absence of citrates or other stabilizing agents in order to study the NP-protein interaction. Four common proteins (lysozyme, bovine serum albumin, cytochrome-C and Hb) were used in this work. Transmission electron microscopy (TEM) and surface enhanced Raman spectroscopy (SERS) were mainly used to study these bioconjugated NPs. TEM images showed Ag NPs with sizes in the 5-40 nm range. The presence of a protein layer surrounding the Ag NPs was also obsd. by TEM. Moreover, the compn. at different points of single bioconjugated NPs was probed by electron energy loss spectroscopy (EELS). The thickness of the protein layer varies in the 3-15 nm range and the Ag NPs are a few nanometers away. This allowed to obtain an enhancement of the Raman signal of the proteins in the anal. of water suspensions of bioconjugates. SERS results showed a broadening of the Raman bands of the proteins which we attribute to the contribution of different configurations of the proteins adsorbed on the Ag NPs surface. Moreover, the assignment of an intense and sharp peak in the low-frequency range to Ag-N vibrations points to the chemisorption of the proteins on the Ag-NPs surface. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFyms77F&md5=24076cfb18cdd0a485e6159151a0befb
- 125 Qin, D. ; Yang, G. ; Wang, Y. ; Zhou, Y. ; Zhang, L. Green Synthesis of Biocompatible Trypsin-Conjugated Ag Nanocomposite with Antibacterial Activity . Appl. Surf. Sci. 2019 , 469 , 528 – 536 , DOI: 10.1016/j.apsusc.2018.11.057 Google Scholar 125 Green synthesis of biocompatible trypsin-conjugated Ag nanocomposite with antibacterial activity Qin, Dezhi; Yang, Guangrui; Wang, Yabo; Zhou, Yanbiao; Zhang, Li Applied Surface Science ( 2019 ), 469 ( ), 528-536 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) In this work, water-sol. Ag nanoparticles were prepd. in aq. soln. by using trypsin as reducing and capping agent. The protein-assisted synthetic strategy eliminates the need of intermediate protecting and linking agents compared with organometallic approach, which is simple, effect, less energy consuming, and closer to the requirements of green chem. The morphol., size and antibacterial activity properties could be controlled by varying exptl. conditions. The results of FT-IR and SDS-PAGE anal. indicated that trypsin mols. could control the nucleation and growth of nanocrystals through chem. interaction between Ag and functional groups of trypsin. The binding of trypsin on the surface of Ag nanoparticles significantly reduced nano-toxicity through capping effect. The trypsin-conjugated Ag nanoparticles exhibited strong antibacterial activity toward both Gram-pos. and Gram-neg. bacteria due to small size and specific morphologies. Compared with traditional antibacterial materials, the water-soly. and biocompatibility make the products more suitable for the application in biol. and medical science. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1eisLzK&md5=2f0e6ad63a7430d4bbd4f9a957088777
- 126 Min, Y. ; Akbulut, M. ; Kristiansen, K. ; Golan, Y. ; Israelachvili, J. The Role of Interparticle and External Forces in Nanoparticle Assembly . Nat. Mater. 2008 , 7 , 527 – 538 , DOI: 10.1038/nmat2206 Google Scholar 126 The role of interparticle and external forces in nanoparticle assembly Min, Younjin; Akbulut, Mustafa; Kristiansen, Kai; Golan, Yuval; Israelachvili, Jacob Nature Materials ( 2008 ), 7 ( 7 ), 527-538 CODEN: NMAACR ; ISSN: 1476-1122 . ( Nature Publishing Group ) A review. The past 20 years have witnessed simultaneous multidisciplinary explosions in exptl. techniques for synthesizing new materials, measuring and manipulating nanoscale structures, understanding biol. processes at the nanoscale, and carrying out large-scale computations of many-atom and complex macromol. systems. These advances have led to the new disciplines of nanoscience and nanoengineering. For reasons that are discussed here, most nanoparticles do not 'self-assemble' into their thermodynamically lowest energy state, and require an input of energy or external forces to 'direct' them into particular structures or assemblies. We discuss why and how a combination of self- and directed-assembly processes, involving interparticle and externally applied forces, can be applied to produce desired nanostructured materials. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXnslKqsrc%253D&md5=53d6916315dccf43b9d72be033f6453a
- 127 Velegol, D. Assembling Colloidal Devices by Controlling Interparticle Forces . J. Nanophotonics 2007 , 1 , 012502 , DOI: 10.1117/1.2759184 Google Scholar There is no corresponding record for this reference.
- 128 Nel, A. ; Xia, T. ; Mädler, L. ; Li, N. Toxic Potential of Materials at the Nanolevel . Science 2006 , 311 , 622 – 627 , DOI: 10.1126/science.1114397 Google Scholar 128 Toxic Potential of Materials at the Nanolevel Nel, Andre; Xia, Tian; Maedler, Lutz; Li, Ning Science (Washington, DC, United States) ( 2006 ), 311 ( 5761 ), 622-627 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) A review. Nanomaterials are engineered structures with at least one dimension of 100 nm or less. These materials are increasingly being used for com. purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and drug carriers. Materials in this size range may approach the length scale at which some specific phys. or chem. interactions with their environment can occur. As a result, their properties differ substantially from those bulk materials of the same compn., allowing them to perform exceptional feats of cond., reactivity, and optical sensitivity. Possible undesirable results of these capabilities are harmful interactions with biol. systems and the environment, with the potential to generate toxicity. The establishment of principles and test procedures to ensure safe manuf. and use of nanomaterials in the marketplace is urgently required and achievable. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XptVyrsg%253D%253D&md5=584e4f8683594cff5ed7bcd039b7cdf3
- 129 Dagastine, R. R. ; Manica, R. ; Carnie, S. L. ; Chan, D. Y. C. ; Stevens, G. W. ; Grieser, F. Dynamic Forces between Two Deformable Oil Droplets in Water . Science 2006 , 313 , 210 – 213 , DOI: 10.1126/science.1125527 Google Scholar 129 Dynamic Forces Between Two Deformable Oil Droplets in Water Dagastine, Raymond R.; Manica, Rogerio; Carnie, Steven L.; Chan, D. Y. C.; Stevens, Geoffrey W.; Grieser, Franz Science (Washington, DC, United States) ( 2006 ), 313 ( 5784 ), 210-213 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) The understanding of static interactions in colloidal suspensions is well established, whereas dynamic interactions more relevant to biol. and other suspended soft-matter systems are less well understood. We present the direct force measurement and quant. theor. description for dynamic forces for liq. droplets in another immiscible fluid. Anal. of this system demonstrates the strong link between interfacial deformation, static surface forces, and hydrodynamic drainage, which govern dynamic droplet-droplet interactions over the length scale of nanometers and over the time scales of Brownian collisions. The results and anal. have direct bearing on the control and manipulation of suspended droplets in soft-matter systems ranging from the emulsions in shampoo to cellular interactions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xmslagu7s%253D&md5=bebc6cc5c21a65e8d934339ac47dc5eb
- 130 Kim, H. Y. ; Sofo, J. O. ; Velegol, D. ; Cole, M. W. ; Lucas, A. A. Van Der Waals Dispersion Forces between Dielectric Nanoclusters . Langmuir 2007 , 23 , 1735 – 1740 , DOI: 10.1021/la061802w Google Scholar 130 Van der Waals Dispersion Forces between Dielectric Nanoclusters Kim, Hye-Young; Sofo, Jorge O.; Velegol, Darrell; Cole, Milton W.; Lucas, Amand A. Langmuir ( 2007 ), 23 ( 4 ), 1735-1740 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Various methods are evaluated for their ability to calc. accurate van der Waals (VDW) dispersion forces between nanoclusters. We compare results for spheres using several methods: the simple Hamaker two-body method, the Lifshitz (DLP) theory with the Derjaguin approxn., the Langbein result for spheres, and our "coupled dipole method" (CDM). The assumptions and shortcomings of each method are discussed. The CDM accounts for all n-body forces, does not assume a continuous and homogeneous dielec. function in each material, accounts for the discreteness of atoms in the particles, can be used for particles of arbitrary shape, and can exactly include the effects of various media. At present, the CDM does not account for retardation. Even for spheres, methods other than the CDM often give errors of 20% or more for VDW dispersion forces between typical dielec. materials. A related calcn. for metals reveals an error in the Hamaker two-body result of nearly a factor of 2. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlektLvE&md5=dcaf19b0de6e014dab68be8d5bf691f6
- 131 Word, J. M. ; Lovell, S. C. ; Richardson, J. S. ; Richardson, D. C. Asparagine and Glutamine: Using Hydrogen Atom Contacts in the Choice of Side-Chain Amide Orientation . J. Mol. Bio. 1999 , 285 , 1735 – 1747 , DOI: 10.1006/jmbi.1998.2401 Google Scholar 131 Asparagine and Glutamine: Using Hydrogen Atom Contacts in the Choice of Side-chain Amide Orientation Word, J. Michael; Lovell, Simon C.; Richardson, Jane S.; Richardson, David C. Journal of Molecular Biology ( 1999 ), 285 ( 4 ), 1735-1747 CODEN: JMOBAK ; ISSN: 0022-2836 . ( Academic Press ) Small-probe contact dot surface anal., with all explicit hydrogen atoms added and their van der Waals contacts included, was used to choose between the two possible orientations for each of 1554 asparagine (Asn) and glutamine (Gln) side-chain amide groups in a dataset of 100 unrelated, high-quality protein crystal structures at 0.9 to 1.7 Å resoln. For the movable-H groups, each connected, closed set of local H-bonds was optimized for both H-bonds and van der Waals overlaps. In addn. to the Asn/Gln "flips", this process included rotation of OH, SH, NH3+, and methionine Me H atoms, flip and protonation state of histidine rings, interaction with bound ligands, and a simple model of water interactions. However, except for switching N and O identity for amide flips (or N and C identity for His flips), no non-H atoms were shifted. Even in these very high-quality structures, about 20 % of the Asn/Gln side-chains required a 180° flip to optimize H-bonding and/or to avoid NH2 clashes with neighboring atoms (incorporating a conservative score penalty which, for marginal cases, favors the assignment in the original coordinate file). The programs Reduce, Probe, and Mage provide not only a suggested amide orientation, but also a numerical score comparison, a categorization of the marginal cases, and a direct visualization of all relevant interactions in both orientations. Visual examn. allowed confirmation of the raw score assignment for about 40 % of those Asn/Gln flips placed within the "marginal" penalty range by the automated algorithm, while uncovering only a small no. of cases whose automated assignment was incorrect because of special circumstances not yet handled by the algorithm. It seems that the H-bond and the at.-clash criteria independently look at the same structural realities: when both criteria gave a clear answer, they agreed every time. But consideration of van der Waals clashes settled many addnl. cases for which H-bonding was either absent or approx. equiv. for the two main alternatives. With this extra information, 86 % of all side-chain amide groups could be oriented quite unambiguously. In the absence of further exptl. data, it would probably be inappropriate to assign many more than this. Some of the remaining 14 % are ambiguous because of coordinate error or inadequacy of the theor. model, but the great majority of ambiguous cases probably occur as a dynamic mix of both flip states in the actual protein mol. The software and the 100 coordinate files with all H atoms added and optimized and with amide flips cor. are publicly available. (c) 1999 Academic Press. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXhtV2ht7g%253D&md5=a3bd044a8652a5ac03e2eb7b9414c2e0
- 132 Arai, T. ; Norde, W. The Behavior of Some Model Proteins at Solid-Liquid Interfaces 1. Adsorption from Single Protein Solutions . Colloids Surf. 1990 , 51 ( C ), 1 – 15 , DOI: 10.1016/0166-6622(90)80127-P Google Scholar 132 The behavior of some model proteins at solid-liquid interfaces. 1. Adsorption from single protein solutions Arai, Takaaki; Norde, Willem Colloids and Surfaces ( 1990 ), 51 ( ), 1-15 CODEN: COSUD3 ; ISSN: 0166-6622 . The adsorption of proteins of similar mol. size and shape on various well-defined surfaces is discussed. The hydrophobicity and the elec. charge d. of both the protein mol. and the sorbent surface as well as the structure stability of the protein mol. were taken as the exptl. variables. The adsorption process was studied by detg. adsorption isotherms and by measuring electrophoretic mobilities and heats of adsorption at varying degrees of coverage of the sorbent surface by the protein. It appeared that proteins of which the structure is stabilized by a large Gibbs energy behave like hard particles: they adsorb on hydrophobic interfaces under all conditions of charge interaction and on hydrophilic surfaces only if electrostatically attracted. Soft proteins, i.e., proteins characterized by a lower structure stability, adsorb on hydrophobic and hydrophilic surfaces under attractive and repulsive electrostatic conditions. These proteins contain an extra driving force for adsorption, related to structure rearrangements in the mol., that outweighs the unfavorable contributions form hydrophilic dehydration and electrostatic repulsion. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXmvFOnuw%253D%253D&md5=0be38d305742fa4a562fc51edff91bee
- 133 Norde, W. ; Giacomelli, C. E. BSA Structural Changes during Homomolecular Exchange between the Adsorbed and the Dissolved States . J. Biotechnol. 2000 , 79 ( 3 ), 259 – 268 , DOI: 10.1016/S0168-1656(00)00242-X Google Scholar 133 BSA structural changes during homomolecular exchange between the adsorbed and the dissolved states Norde, W.; Giacomelli, C. E. Journal of Biotechnology ( 2000 ), 79 ( 3 ), 259-268 CODEN: JBITD4 ; ISSN: 0168-1656 . ( Elsevier Science Ltd. ) The secondary structure and the thermostability of bovine serum albumin (BSA), before adsorption and after homomol. displacement from silica and polystyrene particles, are studied by CD spectroscopy and differential scanning calorimetry. The structural perturbations induced by the hydrophilic silica surface are reversible, i.e. BSA completely regains the native structure and stability after being exchanged. On the other hand, the adsorption on, and subsequent desorption from, polystyrene particles causes irreversible changes in the stability and (secondary) structure of BSA. The exchanged proteins have a higher denaturation temp. and a lower enthalpy of denaturation than native BSA. The α-helix content is reduced while the β-turn fraction is increased in the exchanged mols. Both effects are more pronounced when the protein is displaced from less crowded sorbent surfaces. The irreversible surface-induced conformational change may be related to some aggregation of BSA mols. after being exposed to a hydrophobic surface. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXktV2rtrs%253D&md5=eab9e55e71de8cb4901562775bb82969
- 134 Aubin-Tam, M. E. ; Hamad-Schifferli, K. Gold Nanoparticle-Cytochrome c Complexes: The Effect of Nanoparticle Ligand Charge on Protein Structure . Langmuir 2005 , 21 , 12080 – 12084 , DOI: 10.1021/la052102e Google Scholar 134 Gold Nanoparticle-Cytochrome c Complexes: The Effect of Nanoparticle Ligand Charge on Protein Structure Aubin-Tam, Marie-Eve; Hamad-Schifferli, Kimberly Langmuir ( 2005 ), 21 ( 26 ), 12080-12084 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) We report the effect of nanoparticle ligand charge on the structure of a covalently, site-specifically linked protein. Au nanoparticles with pos., neg., and neutral ligands were appended to a specific cysteine, C102, of Saccharomyces cerevisiae cytochrome c. Conjugates were purified by HPLC or gel electrophoresis. CD spectroscopy shows that changing the nanoparticle ligand dramatically influences the attached cytochrome c structure. The protein retains its structure with neutral ligands but denatures in the presence of charged species. This is rationalized by the electrostatic interaction of amino acids in the local vicinity of C102 with the endgroups of the ligand. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1SgtrfI&md5=75d480b3eb03450e07dd8bee2cf0db56
- 135 Jalab, J. ; Abdelwahed, W. ; Kitaz, A. ; Al-Kayali, R. Green Synthesis of Silver Nanoparticles Using Aqueous Extract of Acacia Cyanophylla and Its Antibacterial Activity . Heliyon 2021 , 7 , e08033 DOI: 10.1016/j.heliyon.2021.e08033 Google Scholar There is no corresponding record for this reference.
- 136 Ghanbar, F. ; Mirzaie, A. ; Ashrafi, F. ; Noorbazargan, H. ; Dalirsaber Jalali, M. ; Salehi, S. ; Sadat Shandiz, S. A. Antioxidant, Antibacterial and Anticancer Properties of Phyto-Synthesised Artemisia Quttensis Podlech Extract Mediated AgNPs . IET Nanobiotechnol 2017 , 11 ( 4 ), 485 – 492 , DOI: 10.1049/iet-nbt.2016.0101 Google Scholar 136 Antioxidant, antibacterial and anticancer properties of phyto-synthesised Artemisia quttensis Podlech extract mediated AgNPs Ghanbar Farinaz; Ashrafi Fatemeh; Mirzaie Amir; Sadat Shandiz Seyed Ataollah; Noorbazargan Hassan; Dalirsaber Jalali Mojgan; Salehi Soheil IET nanobiotechnology ( 2017 ), 11 ( 4 ), 485-492 ISSN: 1751-8741 . The focus of this study is on a rapid and cost-effective approach for the synthesis of silver nanoparticles (AgNPs) using Artemisia quttensis Podlech aerial parts extract and assessment of their antioxidant, antibacterial and anticancer activities. The prepared AgNPs were determined by ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infra-red spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and dynamic light scattering and zeta-potential analysis. The AgNPs and A. quttensis extract were evaluated for their antiradical scavenging activity by 2, 2-diphenyl, 1-picryl hydrazyl assay and anticancer activity against colon cancer (human colorectal adenocarcinoma cell line 29) compared with normal human embryonic kidney (HEK293) cells. Also, the prepared AgNPs were studied for its antibacterial activity. The AgNPs revealed a higher antioxidant activity compared with A. quttensis extract alone. The phyto-synthesised AgNPs and A. quttensis extract showed a dose-response cytotoxicity effect against HT29 and HEK293 cells. As evidenced by Annexin V/propidium iodide staining, the number of apoptotic HT29 cells was significantly enhanced, following treatment with AgNPs as compared with untreated cells. Besides, the antibacterial property of the AgNPs indicated a significant effect against the selected pathogenic bacteria. These present obtained results show the potential applications of phyto-synthesised AgNPs using A. quttensis aerial parts extract. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1crpvVKlug%253D%253D&md5=c1a01e27839657fc35cb452084fc58af
- 137 Emam, M. ; el Raey, M. A. ; Eisa, W. H. ; El- Haddad, A. E. ; Osman, S. M. ; El-Ansari, M. A. ; Rabie, A. G. M. Green Synthesis of Silver Nanoparticles from Caesalpinia Gilliesii (Hook) Leaves: Antimicrobial Activity and in Vitro Cytotoxic Effect against BJ-1 and MCF-7 Cells . J. Appl. Pharm. Sci. 2017 , 7 , 226 – 233 , DOI: 10.7324/JAPS.2017.70831 Google Scholar 137 Green synthesis of silver nanoparticles from Caesalpinia gilliesii (Hook) leaves: antimicrobial activity and in vitro cytotoxic effect against BJ-1 and MCF-7 cells Emam, Mahmoud; el Raey, Mohamed A.; Eisa, Wael H.; El-Haddad, Alaadin E.; Osman, Samir M.; El-Ansari, Mohamed A.; Rabie, Abdel-Gawad M. Journal of Applied Pharmaceutical Science ( 2017 ), 7 ( 8 ), 226-233 CODEN: JAPSHX ; ISSN: 2231-3354 . ( Journal of Applied Pharmaceutical Science ) Green synthesis of silver nanoparticles using Caesalpinia gilliesii (Hook) leaves ext. (70% MeOH) for the first time as a reducing agent were investigated for their antimicrobial and cytotoxic activity (using the MTT assay). After exposing the oxidizing agent of silver ions to C. gilliesii leaves ext., the rapid redn. in the soln. is obsd. due to the construction of silver nanoparticles. The prepd. nanoparticles were elucidated by using UV-visible spectroscopy, Fourier Transforms IR spectroscopy (FT-IR) and transmission electron microscope (TEM). The purified silver nanoparticles demonstrated promising antimicrobial activity against tested pathogens than hydroalcoholic ext. Cell viability by using the MTT assay demonstrated cytotoxic activity of the synthesized Ag NPs with C. gilliesii against normal skin fibroblast (BJ-1) and human breast cancer cell (MCF-7) with IC50= 80.1 and 36.5 μg/mL at 48 h incubation, resp. Depending on the phenolic and flavonoid contents, C. gilliesii could be used for simple, nonhazardous, eco-friendly, cost-effective and efficient synthesis of Ag NPs that can be applied into medicinal field. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisVOrtLzO&md5=28377dce2fd51180b6a859bc2fe2dd7e
- 138 Geetha, N. ; Geetha, T. S. ; Manonmani, P. ; Thiyagarajan, M. Green Synthesis of Silver Nanoparticles Using Cymbopogan Citratus (Dc) Stapf. Extract and Its Antibacterial Activity . Aust.J.Basic Appl. Sci. 2014 , 8 , 324 – 331 , DOI: 10.7324/JAPS.2017.70831 Google Scholar 138 Green synthesis of silver nanoparticles using Cymbopogan citratus (Dc) Stapf. extract and its antibacterial activity Geetha, Natesan; Geetha, Thangarajan Sarojini; Manonmani, Pandiyan; Thiyagarajan, M. Australian Journal of Basic and Applied Sciences ( 2014 ), 8 ( 3 ), 324-331, 8 CODEN: AJBAB3 ; ISSN: 1991-8178 . ( AENSI Publications ) Background: There is an increasing com. demand for nanoparticles due to their wide applicability in different fields such as catalysis, photonics, electronics, biol. labeling, biosensing, drug delivery, antibacterial, and antiviral and gene therapy. Physicochem. methods of nanoparticle synthesis causes environment hazards, so biol. approach has emerged as eco-friendly and alternative method. Cymbopogan citratus (DC) stapf. is commonly known as lemon grass belongs to a family Poaceae. It is a native arom. herb from India and is also cultivated in other tropical and subtropical countries. Objective: The main objective of the study is synthesis and characterization of silver nanoparticles in lemon grass leaves and to study its antibacterial activity. Results: The silver nanoparticles were formed after 3 h of incubation at 37°C using aq. soln. of 5 mM silver nitrate (AgNO3) and synthesized silver nanoparticles were characterized by UV-vis, XRD, SEM,EDS and FTIR. The antibacterial activity of synthesized silver nanoparticles was investigated by disk diffusion method. Conclusion: In the present study silver nanoparticles was synthesized by green route and significant antibacterial activity was also obsd. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtleqsL%252FI&md5=e86406fbd3f51a690d21cd3c11fcc634
- 139 Singh, H. ; Du, J. ; Singh, P. ; Yi, T. H. Ecofriendly Synthesis of Silver and Gold Nanoparticles by Euphrasia Officinalis Leaf Extract and Its Biomedical Applications . Artif. Cells, Nanomed., Biotechnol. 2018 , 46 ( 6 ), 1163 – 1170 , DOI: 10.1080/21691401.2017.1362417 Google Scholar 139 Ecofriendly synthesis of silver and gold nanoparticles by Euphrasia officinalis leaf extract and its biomedical applications Singh, Hina; Du, Juan; Singh, Priyanka; Yi, Tae Hoo Artificial Cells, Nanomedicine, and Biotechnology ( 2018 ), 46 ( 6 ), 1163-1170 CODEN: ACNBCI ; ISSN: 2169-141X . ( Taylor & Francis Ltd. ) Biogenic synthesis of silver (AgNPs) and gold nanoparticles (AuNPs) using aq. ext. of Euphrasia officinalis has been reported. Stable AgNPs and AuNPs were formed on adding aq. solns. of silver nitrate and chloroauric acid with E. officinalis leaf ext., in 19 min and 2 min, resp. The synthesis method used in present study was simple, reliable, rapid, cost effective and ecofriendly. The synthesized nanoparticles were characterized with field emission transmission electron microscopy (FE-TEM), elemental mapping, selected area diffraction pattern (SAED), energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform IR spectroscopy (FTIR). The UV-Vis spectrum confirmed the synthesis of nanoparticles as the absorption band was obsd. at 450 nm for AgNPs and at 558 nm for AuNPs. The TEM images revealed quasi-spherical shape of AgNPs and AuNPs. The size of nanoparticles was detd. to be 40.37 ± 1.8 nm for AgNPs and 49.72 ± 1.2 nm for AuNPs. The zeta potential value demonstrated the neg. surface charge and stable nature of nanoparticles. Cryst. nature of the nanoparticles in the face-centered cubic (fcc) structure was confirmed by the peaks in the XRD pattern and SAED pattern. FTIR results showed the functional groups involved in redn. of silver and gold ions to metal nanoparticles. For biomedical application, the nanoparticles have been explored for anticancer, antibacterial and biofilm inhibition activities. It was obsd. that AgNPs exert anticancer activity against human lung cancer (A549) and human cervical cancer (HeLa) cell lines. On the other hand, AuNPs were able to inhibit only human cervical cancer cells. Furthermore, the AgNPs were active against clin. isolated human pathogens like Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Vibrio parahaemolyticus. Addnl., AgNPs also showed biofilm inhibition activity against S. aureus and P. aeruginosa. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht12lt7bP&md5=0fcb4f5714bc67f6f4e19556dcbb1a2f
- 140 Suchithra, M. R. ; Bhuvaneswari, S. ; Sampathkumar, P. ; Dineshkumar, R. ; Chithradevi, K. ; Beevi farhana noor, M. ; Madhumitha, R. ; Kavisri, M. In Vitro Study of Antioxidant, Antidiabetic and Antiurolithiatic Activity of Synthesized Silver Nanoparticles Using Stem Bark Extracts of Hybanthus Enneaspermus . Biocatal. Agric. Biotechnol. 2021 , 38 , 102219 , DOI: 10.1016/j.bcab.2021.102219 Google Scholar 140 In vitro study of antioxidant, antidiabetic and antiurolithiatic activity of synthesized silver nanoparticles using stem bark extracts of Hybanthus enneaspermus Suchithra, M. R.; Bhuvaneswari, S.; Sampathkumar, P.; Dineshkumar, R.; Chithradevi, K.; Beevi farhana noor, M.; Madhumitha, R.; Kavisri, M. Biocatalysis and Agricultural Biotechnology ( 2021 ), 38 ( ), 102219 CODEN: BABICA ; ISSN: 1878-8181 . ( Elsevier Ltd. ) Diabetes mellitus is an endocrine disorder that affects 85% of the people because of higher sugar level in blood. Due to this metabolic disorder and improper function of organs esp. kidney results in urinary tract infection causing struvite urinary stone. So, in the present study was carried out to study the green synthesized silver nanoparticles using Hybanthus enneaspermus stem bark exts. on antioxidant, antidiabetic and antiurolithiatic activity under in vitro conditions. By the treatment of aq. soln. of 5 mM silver nitrate (AgNO3) with stem bark exts., silver nanoparticles could be quickly synthesized within 1 h. These silver nanoparticles were characterized using UV-Visible spectroscopy, Fourier Transform IR Spectroscopy (FT-IR), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and Dynamic Light Scattering (DLS) for further confirmation. TEM anal. found that the silver nanoparticles are spherical in shape. X-ray diffraction confirmed that silver nanostructure exhibit a fcc. crystal structure. DLS showed that the nanoparticles size is 644.2 nm. By increasing the concn. of silver nanoparticles, wt. of the formed crystals reduced from 0.94 g to 0.13 g in struvite crystals and analyzed by FTIR analyses. This multidisciplinary approach showed a better percentage of inhibition such as antioxidant, antidiabetic and antiurolithiatic activity of silver nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XmvVKkurg%253D&md5=cca6aeec751dbd5326a8c618076575c3
- 141 Schön, G. ; Simon, U. A Fascinating New Field in Colloid Science: Small Ligand-Stabilized Metal Clusters and Their Possible Application in Microelectronics - Part II: Future Directions . Colloid Polym. Sci. 1995 , 273 , 202 – 218 , DOI: 10.1007/BF00657826 Google Scholar There is no corresponding record for this reference.
- 142 Brus, L. Electronic Wave Functions in Semiconductor Clusters: Experiment and Theory . J. Phys. Chem. 1986 , 90 , 2555 – 2560 , DOI: 10.1021/j100403a003 Google Scholar 142 Electronic wave functions in semiconductor clusters: experiment and theory Brus, Louis Journal of Physical Chemistry ( 1986 ), 90 ( 12 ), 2555-60 CODEN: JPCHAX ; ISSN: 0022-3654 . Recent exptl. and theor. work in the size-dependent development of bulk electronic properties in semiconductor crystallites of ∼15 to several hundred are critically reviewed and discussed. Semiconducting electronic properties are explained in chem. valence terminol. These crystallites can be termed "clusters" because they are too small to have bulblike electronic wave functions even though they exhibit bulklike crystal structure. The principal exptl. evidence comes from the recent discovery that liq.-phase pptn. reactions can be controlled to make and stabilize cryst. semiconductor clusters in this size range. The cluster electronic properties can be studied optically in dil. colloidal solns. The cluster internal crystal structure is directly revealed by transmission electron microscopy. The results indicate that the approach of cluster electronic wave functions to the bulk Bloch MOs is exceedingly slow as a function of cluster size. This result can be anal. predicted in terms of the intrinsic electron delocalization present in cryst. materials with strong, directional chem. bonding. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XktFagtr0%253D&md5=480cab9cd92fd4d95d8be577a9bf7e0a
- 143 Wang, Y. ; Herron, N. Nanometer-Sized Semiconductor Clusters: Materials Synthesis, Quantum Size Effects, and Photophysical Properties . J. Phys. Chem. 1991 , 95 , 525 – 532 , DOI: 10.1021/j100155a009 Google Scholar 143 Nanometer-sized semiconductor clusters: materials synthesis, quantum size effects, and photophysical properties Wang, Ying; Herron, N. Journal of Physical Chemistry ( 1991 ), 95 ( 2 ), 525-32 CODEN: JPCHAX ; ISSN: 0022-3654 . A review with 67 refs. Recent advances in the synthesis of semiconductor clusters open a doorway for the systematic study of size-dependent cluster properties in the condensed phase. The size effect on the optical and photophys. properties are discussed. Fundamental concepts are discussed and a discussion is given of recent progress toward the understanding of the quantum size effect and dielec. confinement effect. The current status is discussed of materials synthesis and the prospect for making monodisperse clusters of well-defined surfaces. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXntFWqsw%253D%253D&md5=88fdf459b82252eaf95ab153f495eb6a
- 144 Chen, D. H. ; Chen, Y. Y. Synthesis of Strontium Ferrite Nanoparticles by Coprecipitation in the Presence of Polyacrylic Acid . Mater. Res. Bull. 2002 , 37 , 801 – 810 , DOI: 10.1016/S0025-5408(01)00590-6 Google Scholar 144 Synthesis of strontium ferrite nanoparticles by coprecipitation in the presence of polyacrylic acid Chen, Dong-Hwang; Chen, Yuh-Yuh Materials Research Bulletin ( 2002 ), 37 ( 4 ), 801-810 CODEN: MRBUAC ; ISSN: 0025-5408 . ( Elsevier Science Inc. ) Sr ferrite (SrFe12O19) nanoparticles were prepd. by copptn. in a PAA aq. soln. The av. diam. of the mixed hydroxide ppts. was 3.1 nm. From the thermal anal. by TGA/DTA and the phase anal. by XRD, the appropriate molar ratio of Sr/Fe in aq. soln. was 1/8 and the precursor could yield pure Sr ferrite after calcination at >700°. The av. diams. of the Sr ferrite nanoparticles calcined at 700 and 800° were 34 and 41 nm, resp. The magnetic measurements indicated that their satn. magnetization (57-59 emu/g) reached 85-88% of the theor. one and increased with the decrease of temp. at 5-400 K Their coercivity values (55-67 Oe) were much lower than those reported earlier, revealing the resultant nanoparticles were superparamagnetic. All the magnetic properties obsd. reflected the nature of nanoparticles and also concerned with their morphol. and microstructure. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xis1eiuro%253D&md5=1d458335f0ea2f435e88d47317e092db
- 145 Sharma, R. K. ; Sharma, P. ; Maitra, A. Size-Dependent Catalytic Behavior of Platinum Nanoparticles on the Hexacyanoferrate(III)/Thiosulfate Redox Reaction . J. Colloid Interface Sci. 2003 , 265 , 134 – 140 , DOI: 10.1016/S0021-9797(03)00463-6 Google Scholar 145 Size-dependent catalytic behavior of platinum nanoparticles on the hexacyanoferrate(III)/thiosulfate redox reaction Sharma, Rakesh Kumar; Sharma, Parvesh; Maitra, Amarnath Journal of Colloid and Interface Science ( 2003 ), 265 ( 1 ), 134-140 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Science ) Pt nanoparticles prepd. in reverse micelles were used as catalysts for the electron transfer reaction between hexacyanoferrate(III) and thiosulfate ions. Nanoparticles of av. diam. ranging between 10 and 80 nm were used as catalysts. The kinetic study of the catalytic reaction showed that for a fixed mass of catalyst the catalytic rate did not increase proportionately to the decrease in particle size over the whole range from 10 to 80 nm. The max. reaction rate was obsd. for av. particle diam. of ∼38 nm. Particles below diam. 38 nm exhibit a trend of decreasing reaction rate with the decrease in particle size, while those above diam. 38 nm show a steady decline of reaction rate with increasing size. It was postulated that in the case of particles of av. size <38 nm diam., a downward shift of Fermi level with a consequent increase of band gap energy takes place. As a result, the particles require more energy to pump electrons to the adsorbed ions for the electron transfer reaction. This leads to a reduced reaction rate catalyzed by smaller particles. However, for nanoparticles above diam. 38 nm, the change of Fermi level is not appreciable. These particles exhibit less surface area for adsorption as the particle size is increased. As a result, the catalytic efficiency of the particles is also decreased with increased particle size. The activation energies for the reaction catalyzed by Pt nanoparticles of diams. 12 and 30 nm are ∼18 and 4.8 kJ/mol, resp., indicating that the catalytic efficiency of 12-nm-diam. Pt particles is less than that of particles of diam. 30 nm. Extremely slow reaction rate of uncatalyzed reaction was manifested through a larger activation energy of ∼40 kJ/mol for the reaction. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmtFansrc%253D&md5=1c3b27d76823f90a38fb28cb8a40c71a
- 146 Gao, J. ; Fu, J. ; Lin, C. ; Lin, J. ; Han, Y. ; Yu, X. ; Pan, C. Formation and Photoluminescence of Silver Nanoparticles Stabilized by a Two-Armed Polymer with a Crown Ether Core . Langmuir 2004 , 20 , 9775 – 9779 , DOI: 10.1021/la049197p Google Scholar 146 Formation and Photoluminescence of Silver Nanoparticles Stabilized by a Two-Armed Polymer with a Crown Ether Core Gao, Junpeng; Fu, Jun; Lin, Cuikun; Lin, Jun; Han, Yanchun; Yu, Xiang; Pan, Caiyuan Langmuir ( 2004 ), 20 ( 22 ), 9775-9779 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Ag nanoparticles were synthesized using a two-armed polymer with a crown ether core [poly(styrene)]-dibenzo-18-crown-6-[poly(styrene)] based on the flexibility of the polymer chains and the complex effect of crown ether with Ag+ and Ag. The size of Ag nanoparticles could be tailored by controlling the initial concns. of the polymer and Ag+, and the mol. wt. of the polymer. The emission of Ag nanoparticles was blue-shifted, and the intensity of the photoluminescence of Ag nanoparticles stabilized by the polymer was significantly increased due to the complex effect between the crown ether embedded in the polymer and the Ag nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnvFGns78%253D&md5=bec9fd10e51f49105758d73081eaa161
- 147 Kuo, P. L. ; Chen, W. F. Formation of Silver Nanoparticles under Structured Amino Groups in Pseudo-Dendritic Poly(Allylamine) Derivatives . J. Phys. Chem. B 2003 , 107 , 11267 – 11272 , DOI: 10.1021/jp030116s Google Scholar 147 Formation of Silver Nanoparticles under Structured Amino Groups in Pseudo-dendritic Poly(allylamine) Derivatives Kuo, Ping-Lin; Chen, Wei-Fu Journal of Physical Chemistry B ( 2003 ), 107 ( 41 ), 11267-11272 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) The syntheses of silver nanoparticles stabilized by poly(allylamine) (PAA) and by polyethyleneiminated poly(allylamine) (PAA(EI)n (n = 2, 5.8)) are reported. The architectural effects in particle on the nanoparticle size, size distribution, and agglomeration behavior are detd. from the UV-vis plasmon absorption band and transmission electron microscopic (TEM) analyses. The data show that PAA(EI)n display better stabilizing effects than PAA to prevent silver particles from agglomeration. Different phenomena of the polymer-protected nanoparticles at various silver ion concns. are obsd. and are explained in terms of a mechanism of structure-dependent stabilization. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnsVOjs7c%253D&md5=a3058a27f3f78a79f5c2153989a2c326
- 148 Yan, W. ; Chen, B. ; Mahurin, S. M. ; Schwartz, V. ; Mullins, D. R. ; Lupini, A. R. ; Pennycook, S. J. ; Dai, S. ; Overbury, S. H. Preparation and Comparison of Supported Gold Nanocatalysts on Anatase, Brookite, Rutile, and P25 Polymorphs of TiO 2 for Catalytic Oxidation of CO . J. Phys. Chem. B 2005 , 109 , 10676 – 10685 , DOI: 10.1021/jp044091o Google Scholar 148 Preparation and Comparison of Supported Gold Nanocatalysts on Anatase, Brookite, Rutile, and P25 Polymorphs of TiO2 for Catalytic Oxidation of CO Yan, Wenfu; Chen, Bei; Mahurin, S. M.; Schwartz, V.; Mullins, D. R.; Lupini, Andrew R.; Pennycook, S. J.; Dai, Sheng; Overbury, S. H. Journal of Physical Chemistry B ( 2005 ), 109 ( 21 ), 10676-10685 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Nanosized anatase (≤10 nm), rutile (≤10 nm), and brookite (∼70 nm) titania particles have been successfully synthesized via sonication and hydrothermal methods. Gold was deposited with high dispersion onto the surfaces of anatase, rutile, brookite, and com. titania (P25) supports through a deposition-pptn. (D-P) process. All catalysts were exposed to an identical sequence of treatment and measurements of catalytic CO oxidn. activity. The as-synthesized catalysts have high activity with concomitant Au redn. upon exposure to the reactant stream. Mild redn. at 423 K produces comparably high activity catalysts for every support. Deactivation of the four catalysts was obsd. following a sequence of treatments at temps. up to 573 K. The brookite-supported gold catalyst sustains the highest catalytic activity after all treatments. XRD and TEM results indicate that the gold particles supported on brookite are smaller than those on the other supports following the reaction and pretreatment sequences. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFWgsb8%253D&md5=23b537cb7751e3457a7664ec946b1678
- 149 Ma, H. ; Yin, B. ; Wang, S. ; Jiao, Y. ; Pan, W. ; Huang, S. ; Chen, S. ; Meng, F. Synthesis of Silver and Gold Nanoparticles by a Novel Electrochemical Method . ChemPhysChem 2004 , 5 , 68 – 75 , DOI: 10.1002/cphc.200300900 Google Scholar 149 Synthesis of silver and gold nanoparticles by a novel electrochemical method Ma, Houyi; Yin, Bingsheng; Wang, Shuyun; Jiao, Yongli; Pan, Wei; Huang, Shaoxin; Chen, Shenhao; Meng, Fanjun ChemPhysChem ( 2004 ), 5 ( 1 ), 68-75 CODEN: CPCHFT ; ISSN: 1439-4235 . ( Wiley-VCH Verlag GmbH & Co. KGaA ) Spherical silver and gold nanoparticles with narrow size distributions were conveniently synthesized in aq. soln. by a novel electrochem. method. The technol. keys to the electrochem. synthesis of monodispersed metallic nanoparticles lie in the choice of an ideal stabilizer for the metallic nanoclusters and the use of a rotating platinum cathode. Poly(N-vinylpyrrolidone) (PVP) was chosen as the stabilizer for the silver and gold clusters. PVP not only protects metallic particles from agglomeration, but also promotes metal nucleation, which tends to produce small metal particles. Using a rotating platinum cathode effectively solves the technol. difficulty of rapidly transferring the (electrochem. synthesized) metallic nanoparticles from the cathode vicinity to the bulk soln., avoiding the occurrence of flocculates in the vicinity of the cathode, and ensuring the monodispersity of the particles. The particle size and particle size distribution of the silver and gold nanoparticles were improved by adding sodium dodecyl benzene sulfonate (SDBS) to the electrolyte. The electrochem. synthesized nanoparticles were characterized by TEM and UV/Vis spectroscopy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFKqtLg%253D&md5=340acffa742a7e7a19710a8859057d74
- 150 Fajar, M. N. ; Endarko, E. ; Rubiyanto, A. ; Malek, N. A. N. N. ; Hadibarata, T. ; Syafiuddin, A. A Green Deposition Method of Silver Nanoparticles on Textiles and Their Antifungal Activity . Biointerface Res. Appl. Chem. 2020 , 10 , 4902 – 4907 , DOI: 10.33263/BRIAC101.902907 Google Scholar 150 A green deposition method of silver nanoparticles on textiles and their antifungal activity Fajar, Muhammad Noer; Endarko, Endarko; Rubiyanto, Agus; Malek, Nik Ahmad Nizam Nik; Hadibarata, Tony; Syafiuddin, Achmad Biointerface Research in Applied Chemistry ( 2020 ), 10 ( 1 ), 4902-4907 CODEN: BRACD5 ; ISSN: 2069-5837 . ( Comporter SRL ) This study aims to propose a new green method for the deposition of silver nanoparticles (AgNPs) on textiles without the use of chem. compds. as binders. The deposition of AgNPs on textiles was achieved by immersing textiles in silver nitrate soln. before adding with a natural reducing agent obtained from the extn. of Mikania micrantha. Plasmonic properties of the synthesized AgNPs were characterized using UV-visible (UV-vis) spectroscopy and surface morphol. of textiles was identified using the field-emission SEM (FESEM). In addn., energy-dispersive X-ray spectroscopy was also employed for the characterization. Inhibition zone measurement was performed for evaluating the antifungal capability of textiles attached with AgNPs. This study showed that the attachment of AgNPs to several textile types (cotton, cotton-polyester, silk, and fiber) without the use of binders or other chem. compds. had been successfully achieved. Moreover, all textiles attached with AgNP exhibited effective antifungal activity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlOmtb3I&md5=2dc56f4934009ffb0a28e08e8a0f964d
- 151 Chandra, A. ; Bhattarai, A. ; Yadav, A. K. ; Adhikari, J. ; Singh, M. ; Giri, B. Green Synthesis of Silver Nanoparticles Using Tea Leaves from Three Different Elevations . ChemistrySelect 2020 , 5 , 4239 – 4246 , DOI: 10.1002/slct.201904826 Google Scholar 151 Green Synthesis of Silver Nanoparticles Using Tea Leaves from Three Different Elevations Chandra, Abhishek; Bhattarai, Ajaya; Yadav, Ashok K.; Adhikari, Janak; Singh, Man; Giri, Basant ChemistrySelect ( 2020 ), 5 ( 14 ), 4239-4246 CODEN: CHEMUD ; ISSN: 2365-6549 . ( Wiley-VCH Verlag GmbH & Co. KGaA ) Green synthesis of nanoparticles offers numerous advantages over the conventional methods. This work provides a comprehensive understanding on the effect of tea cultivation elevation on the formation of silver nanoparticles (AgNPs) using green tea (Camellia Sinensis) leaves. The green tea leaves were collected from three different elevations: 86, 1700, and 2000 m above sea level in eastern Nepal. We found that AgNPs synthesized using tea leaves from 1700 m were homogeneously dispersed and smallest size, when compared to AgNPs synthesized using tea leaves from remaining two elevations. All aq. dispersed AgNPs were sensitive towards mercury (II) ion over a range of other metal ions tested. However, the AgNPs synthesized using tea leaves from 1700 m resulted in better detection limit of 9.79 muM for sensing mercury (II) ions. Interestingly, the nanoparticles when addnl. stabilized in aq. trimethyloctylammonium bromide, a cationic surfactant among seven other surfactants tested, improved the detection limit to 0.71 muM. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksFelsbo%253D&md5=fda1579f39fd69d71a8d310ddd6e1adc
- 152 Salehizadeh, H. ; Hekmatian, E. ; Sadeghi, M. ; Kennedy, K. Synthesis and Characterization of Core-Shell Fe3O4-Gold-Chitosan Nanostructure . J.Nanobiotechnol. 2012 , 10 , 3 , DOI: 10.1186/1477-3155-10-3 Google Scholar 152 Synthesis and characterization of core-shell Fe3O4-gold-chitosan nanostructure Salehizadeh, Hossein; Hekmatian, Elham; Sadeghi, Meisam; Kennedy, Kevin Journal of Nanobiotechnology ( 2012 ), 10 ( ), 3 CODEN: JNOAAO ; ISSN: 1477-3155 . ( BioMed Central Ltd. ) Fe3O4-gold-chitosan core-shell nanostructure can be used in biotechnol. and biomedical applications such as magnetic biosepn., water and wastewater treatment, biodetection and bioimaging, drug delivery, and cancer treatment. Magnetite nanoparticles with an av. size of 9.8 nm in diam. were prepd. using by pptn. A gold-coated Fe3O4 monotonous core-shell nanostructure was produced with an av. size of 15 nm in diam. by glucose redn. of Au3+ which is then stabilized with a chitosan cross linked by formaldehyde. The results of analyses with x-ray diffraction (XRD), FTIR, TEM, and AFM indicated that the nanoparticles were regularly shaped, and agglomerate-free, with a narrow size distribution. Conclusions: A rapid, mild method for synthesizing Fe3O4-gold nanoparticles using chitosan was investigated. A magnetic core-shell-chitosan nanocomposite, including both the supermagnetic properties of iron oxide and the optical characteristics of colloidal gold nanoparticles, was prepd. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1eju7k%253D&md5=c9b35a3aabd425191c40989d2e0f14a1
- 153 Bruchez, M. ; Moronne, M. ; Gin, P. ; Weiss, S. ; Alivisatos, A. P. Semiconductor Nanocrystals as Fluorescent Biological Labels . Science 1998 , 281 , 2013 – 2016 , DOI: 10.1126/science.281.5385.2013 Google Scholar 153 Semiconductor nanocrystals as fluorescent biological labels Bruchez, Marcel, Jr.; Moronne, Mario; Gin, Peter; Weiss, Shimon; Alivisatos, A. Paul Science (Washington, D. C.) ( 1998 ), 281 ( 5385 ), 2013-2016 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) Semiconductor nanocrystals were prepd. for use as fluorescent probes in biol. staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, sym. emission spectrum and are photochem. stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual-emission, single-excitation labeling expt. on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKgurw%253D&md5=db36fdbbfbc2facf264c3f98c1c8efcb
- 154 Chan, W. C. W. ; Nie, S. Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection . Science 1998 , 281 , 2016 – 2018 , DOI: 10.1126/science.281.5385.2016 Google Scholar 154 Quantum dot bioconjugates for ultrasensitive nonisotopic detection Chan, Warren C. W.; Nile, Shuming Science (Washington, D. C.) ( 1998 ), 281 ( 5385 ), 2016-2018 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomols. for use in ultra-sensitive biol. detection. In comparison with org. dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-sol. and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomols. recognized specific antibodies or antigens. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKnsrk%253D&md5=481c7a81438f03ca6c871d30afde6eb3
- 155 Dubertret, B. ; Calame, M. ; Libchaber, A. J. Single-Mismatch Detection Using Gold-Quenched Fluorescent Oligonucleotid . Nat. Biotechnol. 2001 , 19 , 365 – 370 , DOI: 10.1038/86762 Google Scholar 155 Single-mismatch detection using gold-quenched fluorescent oligonucleotides Dubertret, Benoit; Calame, Michel; Libchaber, Albert J. Nature Biotechnology ( 2001 ), 19 ( 4 ), 365-370 CODEN: NABIF9 ; ISSN: 1087-0156 . ( Nature America Inc. ) Here we describe a hybrid material composed of a single-stranded DNA (ssDNA) mol., a 1.4 nm diam. gold nanoparticle, and a fluorophore that is highly quenched by the nanoparticle through a distance-dependent process. The fluorescence of this hybrid mol. increases by a factor of as much as several thousand as it binds to a complementary ssDNA. We show that this composite mol. is a different type of mol. beacon with a sensitivity enhanced up to 100-fold. In competitive hybridization assays, the ability to detect single mismatch is eightfold greater with this probe than with other mol. beacons. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXis1Smsbk%253D&md5=47167a2f825fd18295e2a7f8d67988bc
- 156 Reynolds, R. A. ; Mirkin, C. A. ; Letsinger, R. L. Homogeneous, Nanoparticle-Based Quantitative Colorimetric Detection of Oligonucleotides . J. Am. Chem. Soc. 2000 , 122 , 3795 – 3796 , DOI: 10.1021/ja000133k Google Scholar 156 Homogeneous, Nanoparticle-Based Quantitative Colorimetric Detection of Oligonucleotides Reynolds, Robert A., III; Mirkin, Chad A.; Letsinger, Robert L. Journal of the American Chemical Society ( 2000 ), 122 ( 15 ), 3795-3796 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A modified method for a heterogeneous colorimetric oligonucleotide detection system based on alkylthiol-functionalized oligonucleotide-modified gold probes is described. Gold particles (50 and 100 nm) are modified and stabilized using dithiane epiandrosterone-functionalized oligonucleotides. Assay sensitivity and larger detection ranges are increased with increasing particle size. While the 100 nm gold probes are more sensitive to lower oligonucleotide concns. than the 50 nm probes, adequate endpoints were not obtainable with the 100 nm probes due to aggregate sedimentation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXitFGjsbc%253D&md5=30204f1197a9b90f97eadd06489f7e08
- 157 Alivisatos, A. P. ; Johnsson, K. P. ; Peng, X. ; Wilson, T. E. ; Loweth, C. J. ; Bruchez, M. P. ; Schultz, P. G. Organization of “nanocrystal Molecules” Using DNA . Nature 1996 , 382 , 609 – 611 , DOI: 10.1038/382609a0 Google Scholar 157 Organization of 'nanocrystal molecules' using DNA Alivisatos, A. Paul; Johnsson, Kai P.; Peng, Xiaogang; Wilson, Troy E.; Loweth, Colin J.; Bruchez, Marcel P., Jr.; Schultz, Peter G. Nature (London) ( 1996 ), 382 ( 6592 ), 609-611 CODEN: NATUAS ; ISSN: 0028-0836 . ( Macmillan Magazines ) The authors describe a strategy for the synthesis of 'nanocrystal mols.', in which discrete nos. of Au nanocrystals are organized into spatially defined structures based on Watson-Crick base-pairing interactions. The authors attach single-stranded DNA oligonucleotides of defined length and sequence to individual nanocrystals, and these assemble into dimers and trimers on addn. of a complementary single-stranded DNA template. The authors anticipate that this approach should allow the construction of more complex two- and three-dimensional assemblies. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XltVWqsrY%253D&md5=27e1eb981a0cfd51907eff5a5a105f50
- 158 He, W. ; Zhou, Y. T. ; Wamer, W. G. ; Boudreau, M. D. ; Yin, J. J. Mechanisms of the PH Dependent Generation of Hydroxyl Radicals and Oxygen Induced by Ag Nanoparticles . Biomaterials 2012 , 33 , 7547 – 7555 , DOI: 10.1016/j.biomaterials.2012.06.076 Google Scholar 158 Mechanisms of the pH dependent generation of hydroxyl radicals and oxygen induced by Ag nanoparticles He, Weiwei; Zhou, Yu-Ting; Wamer, Wayne G.; Boudreau, Mary D.; Yin, Jun-Jie Biomaterials ( 2012 ), 33 ( 30 ), 7547-7555 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) Many of the chem. and biol. effects of silver nanoparticles (Ag NPs) are attributed to the generation of reactive oxygen species (ROS). ESR spectroscopy was used to provide direct evidence for generating ROS during decompn. of H2O2 assisted by Ag NPs. Hydroxyl radical formation was obsd. under acidic conditions and was accompanied by dissoln. of Ag NPs. In contrast, evolution of O2 was obsd. in alk. solns. contg. H2O2 and Ag NPs; however, no net dissoln. of Ag NPs was obsd. due to re-redn. of Ag+ as evidenced by a cyclic reaction. Since H2O2 is a biol. relevant product being continuously generated in cells, these results obtained under conditions mimicking different biol. microenvironments may provide insights for finding new biomedical applications for Ag NPs and for risk assessment. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtVKnur3L&md5=2f904d76a059d32c69310bcfb930ddc9
- 159 Arora, S. ; Jain, J. ; Rajwade, J. M. ; Paknikar, K. M. Cellular Responses Induced by Silver Nanoparticles: In Vitro Studies . Toxicol. Lett. 2008 , 179 , 93 – 100 , DOI: 10.1016/j.toxlet.2008.04.009 Google Scholar 159 Cellular responses induced by silver nanoparticles: In vitro studies Arora, S.; Jain, J.; Rajwade, J. M.; Paknikar, K. M. Toxicology Letters ( 2008 ), 179 ( 2 ), 93-100 CODEN: TOLED5 ; ISSN: 0378-4274 . ( Elsevier B.V. ) A systematic study on the in vitro interactions of 7-20 nm spherical silver nanoparticles (SNP) with HT-1080 and A431 cells was undertaken as a part of an on-going program in our lab. to develop a topical antimicrobial agent for the treatment of burn wound infections. Upon exposure to SNP (up to 6.25 μg/mL), morphol. of both the cell types remained unaltered. However, at higher concns. (6.25-50 μg/mL) cells became less polyhedral, more fusiform, shrunken and rounded. IC50 values for HT-1080 and A431 as revealed by XTT assay were 10.6 and 11.6 μg/mL, resp. When the cells were challenged with ∼1/2 IC50 concn. of SNP (6.25 μg/mL), clear signs of oxidative stress, i.e. decreased GSH (∼2.5-folds in HT-1080, ∼2-folds in A431) and SOD (∼1.6-folds in HT-1080, 3-folds in A431) as well as increased lipid peroxidn. (∼2.5-folds in HT-1080, ∼2-folds in A431) were seen. Changes in the levels of catalase and GPx in A431 cells were statistically insignificant in both cell types. DNA fragmentation in SNP-exposed cells suggested apoptosis. When the apoptotic thresholds of SNP were monitored with caspase-3 assay the concns. required for the onset of apoptosis were found to be much lower (0.78 μg/mL in HT-1080, 1.56 μg/mL in A431) than the necrotic concn. (12.5 μg/mL in both cell types). These results can be used to define a safe range of SNP for the intended application as a topical antimicrobial agent after appropriate in vivo studies. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFKrtrw%253D&md5=2de234ca0852a0e3305120e2e4cf7b3a
- 160 Yang, E. J. ; Kim, S. ; Kim, J. S. ; Choi, I. H. Inflammasome Formation and IL-1β Release by Human Blood Monocytes in Response to Silver Nanoparticles . Biomaterials 2012 , 33 , 6858 – 6867 , DOI: 10.1016/j.biomaterials.2012.06.016 Google Scholar 160 Inflammasome formation and IL-1β release by human blood monocytes in response to silver nanoparticles Yang, Eun-Jeong; Kim, Seungjae; Kim, Jong Soo; Choi, In-Hong Biomaterials ( 2012 ), 33 ( 28 ), 6858-6867 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) In this study, the immunol. effect of silver nanoparticles on innate immunity was investigated using primary human monocytes. After exposure to silver nanoparticles, prodn. of IL-1β, a crit. cytokine involved in induction of innate immunity, significantly increased as particle size decreased. These results suggest that silver nanoparticles may evoke an immunol. active state. The size effect of silver nanoparticles on IL-1β prodn. was also further investigated. 5 Nm and 28 nm silver nanoparticles induced inflammasome formation and subsequent caspase-1 activation. Using inhibitors, we found exposure to silver nanoparticles caused leakage of cathepsins from lysosomes and efflux of intracellular K+. These two events induced superoxide within mitochondrial membranes, leading to inflammasome formation. 5 Nm silver nanoparticles produced more hydrogen peroxide and were more cytotoxic than 28 nm silver nanoparticles, suggesting the balance between superoxide and hydrogen peroxide governs cell fate, death or activation. Moreover, these findings also suggest that the immunol. significance of silver nanoparticles should be considered with respect to their capacity to synergistically activate immune responses. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xps1Klsrw%253D&md5=2ab339ae718603168c8524753f906433
- 161 Almofti, M. R. ; Ichikawa, T. ; Yamashita, K. ; Terada, H. ; Shinohara, Y. Silver Ion Induces a Cyclosporine A-Insensitive Permeability Transition in Rat Liver Mitochondria and Release of Apoptogenic Cytochrome C . J. Biochem. 2003 , 134 , 43 – 49 , DOI: 10.1093/jb/mvg111 Google Scholar 161 Silver ion induces a cyclosporin A-insensitive permeability transition in rat liver mitochondria and release of apoptogenic cytochrome c Almofti, Mohamad Radwan; Ichikawa, Tomokazu; Yamashita, Kikuji; Terada, Hiroshi; Shinohara, Yasuo Journal of Biochemistry ( 2003 ), 134 ( 1 ), 43-49 CODEN: JOBIAO ; ISSN: 0021-924X . ( Japanese Biochemical Society ) Various reagents are known to open the mitochondrial permeability pore (PTP) and induce a permeability transition (PT), releasing apoptogenic proteins from the intermembrane space and triggering apoptosis. In this study, we examd. the effect of Ag+, a known cytotoxic sulfhydryl-reactive heavy metal, on isolated rat liver mitochondria. The following results were obtained: (1) Upon addn., Ag+ instantly induced mitochondrial swelling and acceleration of respiration. (2) Cyclosporin A, a specific inhibitor of classical PT, was ineffective against the effect of Ag+, indicating that silver ions induced non-classic PT. (3) Sulfhydryl reagents such as reduced glutathione completely inhibited the effects of Ag+ on the mitochondria. (4) Exptl. results using polyethylene glycol indicated that Ag+ induced opening of a pore in the inner mitochondrial membrane, which could be PTP of another open state or a distinct pore. (5) Electron microscopic anal. of mitochondria treated with Ag+ showed a novel mitochondrial configuration that was apparently different from that of normal mitochondria or Ca2+-treated mitochondria. (6) Ag+ also induced the release of apoptogenic cytochrome c in a CsA-insensitive but GSH-sensitive manner. These results suggest that Ag+ promotes a nonclassical permeability increase in the mitochondrial inner membrane that is clearly distinguishable from the classical PT and releases apoptogenic cytochrome c in a classical PT-independent manner. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnslGluro%253D&md5=2c4e18ddcebbf9b2fda1f76c6748298c
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- 10 Philip, D. Honey Mediated Green Synthesis of Gold Nanoparticles . Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2009 , 73 , 650 – 653 , DOI: 10.1016/j.saa.2009.03.007 10 Honey mediated green synthesis of gold nanoparticles Philip, Daizy Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy ( 2009 ), 73A ( 4 ), 650-653 CODEN: SAMCAS ; ISSN: 1386-1425 . ( Elsevier B.V. ) Bio-directed synthesis of nanoparticles is of interest to biologists, chemists and materials scientists. The biosynthesis of gold nanoparticles has been carried out by several groups of scientists by using plants, fungi and bacteria. Now a greener synthesis of Au nanoparticles is reported by using natural honey as a reducing and capping agent. By adjusting the concns. of HAuCl4 and honey in aq. solns., colloids having a larger propensity of either anisotropic or spherical nanocrystals could be obtained at room temp. The nanoparticles obtained were characterized by UV-visible spectra, high-resoln. TEM and XRD. The spherical particles obtained had a diam. of ∼15 nm as shown by XRD patterns and TEM images. The high crystallinity with the fcc. phase is evidenced by bright circular spots in SAED pattern and clear lattice fringes in the high-resoln. TEM image. FTIR measurements were carried out to identify the possible biomols. responsible for capping and efficient stabilization of the Au nanoparticles synthesized using honey. The carboxylic acid group vibrations and amide I and II bands indicate the binding of protein with Au surfaces through the amine group rather than the carboxyl group. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnt1emtb4%253D&md5=c92e0079c884dc369aa705cf760454c0
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- 12 Jacob, J. A. ; Naumov, S. ; Mukherjee, T. ; Kapoor, S. Preparation, Characterization, Surface Modification and Redox Reactions of Silver Nanoparticles in the Presence of Tryptophan . Colloids Surf., B 2011 , 87 , 498 – 504 , DOI: 10.1016/j.colsurfb.2011.06.017 12 Preparation, characterization, surface modification and redox reactions of silver nanoparticles in the presence of tryptophan Jacob, Jasmine A.; Naumov, Sergej; Mukherjee, Tulsi; Kapoor, Sudhir Colloids and Surfaces, B: Biointerfaces ( 2011 ), 87 ( 2 ), 498-504 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) The synthesis and characterization of water-sol. dispersions of Ag nanoparticles by the redn. of AgNO3 using tryptophan under alk. synthesis conditions are reported. The Ag nanoparticle formation was very slow at low concn. and rapid at extremes. For surface modification and redox reactions, manipulating the interparticles interaction controlled the size of Ag nanoparticles aggregates. Our results suggest that the replacement of the BH4 - ions adsorbed on the nanoparticle surface by tryptophan destabilizes the particles and further caused aggregation. A mechanism is proposed for the formation of silver nanoparticles by tryptophan. The exptl. results are supported by theor. calcns. The Ag nanoparticles were characterized by UV-vis absorption, dynamic light scattering and transmission electron microscopy techniques. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptVyhu74%253D&md5=e40a8278918d627415075cce60a101e7
- 13 Rafey, A. ; Shrivastavaa, K. B. L. ; Iqbal, S. A. ; Khan, Z. Growth of Ag-Nanoparticles Using Aspartic Acid in Aqueous Solutions . J. Colloid Interface Sci. 2011 , 354 , 190 – 195 , DOI: 10.1016/j.jcis.2010.10.046 13 Growth of Ag-nanoparticles using aspartic acid in aqueous solutions Rafey, Abu; Shrivastavaa, K. B. L.; Iqbal, Sayed Aftab; Khan, Zaheer Journal of Colloid and Interface Science ( 2011 ), 354 ( 1 ), 190-195 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier B.V. ) Spectrophotometric, kinetic, and transmission electron microscopic (TEM) data for the formation of Ag-nanoparticles using aspartic acid (Asp) as reductant are reported for the first time. In the formation of transparent silver sols, an alk. medium is required. The silver nanoparticles are spherical, uniform particle size, and strongly depend on the [Asp]. The apparent rate const. decreases with [Asp] (from 4.0 to 24.0 × 10-4 mol dm-3, the rate consts. decreased from 2.6 × 10-4 to 0.3 × 10-4 s-1). For a certain reaction time, i.e., 30 min, the absorbance of the silver sol first increased until it reached a max., and then decreased with [Asp]. Kinetic and TEM results indicate that the size of the Ag-nanoparticles depends on the [Asp]. It is proposed that the oxidn. of Asp occurs by the adsorbed Ag+ ions on the surface of Ag2O particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsFyis7%252FL&md5=07d368b5a24857fa4a066ff93e65f579
- 14 Khan, Z. ; Talib, A. Growth of Different Morphologies (Quantum Dots to Nanorod) of Ag-Nanoparticles: Role of Cysteine Concentrations . Colloids Surf., B 2010 , 76 , 164 – 169 , DOI: 10.1016/j.colsurfb.2009.10.029 14 Growth of different morphologies (quantum dots to nanorod) of Ag-nanoparticles: Role of cysteine concentrations Khan, Zaheer; Talib, Abou Colloids and Surfaces, B: Biointerfaces ( 2010 ), 76 ( 1 ), 164-169 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) This work describes an easy chem. method for the prepn. of orange-red color silver sol by the cysteine redn. of silver (I) in the presence of cetyltrimethylammonium bromide (CTAB). The obtained sol was found to have very small particles in the order of quantum dots for the first time. Transmission electron microscope (TEM) images show that the silver sol consists of aggregated as well as crosslinking arrangement of spherical silver quantum dots (size in the range ca. ≤16 nm). In addn., the authors obsd. the changes in the morphologies of the Ag-nanoparticles from quantum dots to nanorod of diam. 60 nm and pearl-necklace shaped which occurred due to the crosslinking aggregation of silver quantum dots. For a certain reaction time, i.e., 100 min, the absorbance of reaction mixt. first increased until it reached a max., then decreased with [cysteine]. The rate of Ag-nanoparticles formation decreases with the increase in [cysteine] whereas [CTAB] and [Ag+] have no effect on the reaction rate. Interestingly, at higher [cysteine] (≥20.0 × 10-4 mol dm-3), white ppt. was formed instead of transparent silver sol. Cysteine acts as a reducing, crosslinking, stabilizing and buffering agent during the growth of different shape and size of silver nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXotlSgsA%253D%253D&md5=84ed26736d2c67c93fd131146da4c994
- 15 de Matos, R. A. ; Courrol, L. C. Biocompatible Silver Nanoparticles Prepared with Amino Acids and a Green Method . Amino Acids 2017 , 49 ( 2 ), 379 – 388 , DOI: 10.1007/s00726-016-2371-4 15 Biocompatible silver nanoparticles prepared with amino acids and a green method de Matos Ricardo Almeida; Courrol Lilia Coronato Amino acids ( 2017 ), 49 ( 2 ), 379-388 ISSN: . The synthesis of nanoparticles is usually carried out by chemical reduction, which is effective but uses many toxic substances, making the process potentially harmful to the environment. Hence, as part of the search for environmentally friendly or green synthetic methods, this study aimed to produce silver nanoparticles (AgNPs) using only AgNO3, Milli-Q water, white light from a xenon lamp (Xe) and amino acids. Nanoparticles were synthetized using 21 amino acids, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by UV-Vis, zeta potential measurements and transmission electron microscopy. The synthesis of silver nanoparticles with tryptophan and tyrosine, methionine, cystine and histidine was possible through photoreduction method. Spherical nanoparticles were produced, with sizes ranging from 15 to 30 nm. Tryptophan does not require illumination nor heating, and the solution color changes immediately after the mixing of reagents if sodium hydroxide is added to the solution (pH = 10). The Xe illumination acts as sodium hydroxide in the nanoparticles synthesis, releases H(+) and allows the reduction of silver ions (Ag(+)) in metallic silver (Ag(0)). >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sjhtlCisw%253D%253D&md5=061cd69078926663ebc2e09c1231c497
- 16 Huang, Y.-F. ; Lin, Y.-W. ; Chang, H.-T. Growth of Various Au–Ag Nanocomposites from Gold Seeds in Amino Acid Solutions . Nanotechnology 2006 , 17 , 4885 – 4894 , DOI: 10.1088/0957-4484/17/19/018 16 Growth of various Au-Ag nanocomposites from gold seeds in amino acid solutions Huang, Yu-Fen; Lin, Yang-Wei; Chang, Huan-Tsung Nanotechnology ( 2006 ), 17 ( 19 ), 4885-4894 CODEN: NNOTER ; ISSN: 0957-4484 . ( Institute of Physics Publishing ) In this paper, we describe an easy procedure for the prepn. of differently shaped and sized Au-Ag nanocomposites from gold nanorod (AuNR) seeds in various amino acid solns.-arginine (Arg), cysteine (Cys), glycine (Gly), glutamate (Glu), glutamine (Gln), histidine (His), lysine (Lys), and methionine (Met), resp.-at values of pH ranging from 8.0 to 11.5. Our results suggest that the pH, the nature of the amino acid, and its concn. all have significant impact on the prepn. of Au-Ag nanocomposites; these factors exhibit their effects mainly through control over the reducing ability of ascorbate and/or its recognition capability, as well as through control over the surface charges of the amino acids on the AuNRs. Depending on the value of pH, we were able to prep. I-shaped, dumbbell-shaped, and/or sphere-shaped Au-Ag nanocomposites in 0.1 M solns. of Arg, Gly, Glu, Gln, Lys, and Met. In His solns. at pH 8.0 and 9.0, we obtained peanut-shaped Au-Ag nanocomposites. Corn-shaped Au-Ag nanocomposites were prepd. in 0.1 M Met solns. (pH 9.0 and 10.0). By controlling the Lys concn. at pH 10.0, we synthesized pearl-necklace-shaped Au-Ag nanoparticles and Au-Ag wires. Based on the TEM images, we conclude that this simple and reproducible synthetic approach allows prepn. of high-quality (>87%, beside >77% in solns.) Au-Ag nanocomposites with various shapes and sizes under different conditions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1Klt7nP&md5=1efa52b3fe8ba9f149b78caa627c81d2
- 17 Mocanu, A. ; Cernica, I. ; Tomoaia, G. ; Bobos, L. D. ; Horovitz, O. ; Tomoaia-Cotisel, M. Self-Assembly Characteristics of Gold Nanoparticles in the Presence of Cysteine . Colloids Surf., A 2009 , 338 , 93 – 101 , DOI: 10.1016/j.colsurfa.2008.12.041 17 Self-assembly characteristics of gold nanoparticles in the presence of cysteine Mocanu, Aurora; Cernica, Ileana; Tomoaia, Gheorghe; Bobos, Liviu-Dorel; Horovitz, Ossi; Tomoaia-Cotisel, Maria Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2009 ), 338 ( 1-3 ), 93-101 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Gold nanoparticles in aq. dispersions were prepd. by two methods, using sodium citrate as redn. agent, and their interaction with -cysteine was investigated. UV-vis, dynamic light scattering (DLS) and zeta potential measurements were used for phys. and chem. characterization of mixts. with different gold:cysteine ratios, coupled with transmission electron microscopy (TEM) and at. force microscopy (AFM) observations. Even a dild. (0.001 M) cysteine soln. leads to a rapid assembly of gold nanoparticles and a broad absorption band at longer wavelength (characteristic for the aggregation of gold nanoparticles) develops and surpasses rapidly the peak of non-aggregated gold particles. TEM images for gold nanoparticles mixed with a 0.001 M cysteine soln. show randomly arranged aggregates of gold nanoparticles on TEM carbon coated copper grids. AFM images indicate a rather ordered surface of self-assembled monolayers deposited on silanized glass. From thermodn. considerations on the protolytic equil. in aq. cysteine solns., the species present at different pH values were ascertained. A possible model for cysteine binding to gold nanoparticles and for the formation of gold particle assemblies is also suggested. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitF2ntrw%253D&md5=35645d1cdddcabebfd5f588d4c3201e1
- 18 Zare, D. ; Khoshnevisan, K. ; Barkhi, M. ; Tahami, H. V. Fabrication of Capped Gold Nanoparticles by Using Various Amino Acids . J. Exp. Nanosci. 2014 , 9 , 957 – 965 , DOI: 10.1080/17458080.2012.752582 18 Fabrication of capped gold nanoparticles by using various amino acids Zare, Davood; Khoshnevisan, Kamyar; Barkhi, Mohammad; Tahami, Hamed Vakili Journal of Experimental Nanoscience ( 2014 ), 9 ( 9 ), 957-965 CODEN: JENOBX ; ISSN: 1745-8080 . ( Taylor & Francis Ltd. ) The prodn. of gold nanoparticles (GNPs) by amino acid is one of the most attractive and interesting subjects in nanobiotechnol. In this study, amino acids have been utilized as a reducing agent and also an agent for capping GNPs. The GNPs were prepd. using a redn. soln. contg. gold cations with optimum concn. of gold salt (5 mM), and also functionalised by glutamic acid, phenylalanine and tryptophan with optimum concn. of amino acids (25 mM). The optimum condition of gold soln. and amino acids were achieved by UV-visible spectroscopy. The size of nanoparticles was obtained 5-20, 10-20 and 20-30 nm, resp., by transmission electron microscopy and dynamic light scattering techniques. The results obtained from exptl. and quantum calcns. confirm that amino acids have strong bond while they have anion binding. Moreover, the free carboxylic groups of capped GNPs are one of the suitable and capable beads for binding biol. agents. As a result, the medical applications of amino acids and proteins can be used as a practical method due to the strong interaction of peripheral amine groups with nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXit1Wqtbw%253D&md5=fd8536febae3520771e98dd489bb7892
- 19 Zare, D. ; Akbarzadeh, A. ; Barkhi, M. ; Khoshnevisan, K. ; Bararpour, N. ; Noruzi, M. ; Tabatabaei, M. L-Arginine and L-Glutamic Acid Capped Gold Nanoparticles at Physiological PH: Synthesis and Characterization Using Agarose Gel Electrophoresis . Synth. React. Inorg., Met.-Org., Nano-Met. Chem. 2012 , 42 , 266 – 272 , DOI: 10.1080/15533174.2011.609855 19 L-Arginine and L-Glutamic Acid Capped Gold Nanoparticles at Physiological pH: Synthesis and Characterization Using Agarose Gel Electrophoresis Zare, Davood; Akbarzadeh, Azim; Barkhi, Mohammad; Khoshnevisan, Kamyar; Bararpour, Nasim; Noruzi, Masumeh; Tabatabaei, Meisam Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry ( 2012 ), 42 ( 2 ), 266-272 CODEN: SRIMDO ; ISSN: 1553-3174 . ( Taylor & Francis, Inc. ) The synthesis of amino-acid-capped gold nanoparticles (GNPs) and their characterization using agarose gel electrophoresis are reported. The GNPs were capped with L-Arginine and L-Glutamic acids at different pH. At the physiol. pH, the results obtained revealed that the interactions between L-Arginine, L-Glutamic acid, and GNPs were of the electrostatic and covalent/ coordinate types, resp. The capped GNPs possessing free amine/carboxylic groups could play an important role in conjugating biomols. (e.g., proteins) in various nanobiotechnol. applications. In addn., if the pH of the target environment is const., capped GNPs bound electrostatically are preferred and when variable, then amino-acid-capped GNPs bound covalently/ coordinately are recommended. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xkslaqu7s%253D&md5=95d6b592f5012385764a51b78f212a8d
- 20 Selvakannan, P. R. ; Mandal, S. ; Phadtare, S. ; Gole, A. ; Pasricha, R. ; Adyanthaya, S. D. ; Sastry, M. Water-Dispersible Tryptophan-Protected Gold Nanoparticles Prepared by the Spontaneous Reduction of Aqueous Chloroaurate Ions by the Amino Acid . J. Colloid Interface Sci. 2004 , 269 , 97 – 102 , DOI: 10.1016/S0021-9797(03)00616-7 20 Water-dispersible tryptophan-protected gold nanoparticles prepared by the spontaneous reduction of aqueous chloroaurate ions by the amino acid Selvakannan, P. R.; Mandal, Saikat; Phadtare, Sumant; Gole, Anand; Pasricha, Renu; Adyanthaya, S. D.; Sastry, Murali Journal of Colloid and Interface Science ( 2004 ), 269 ( 1 ), 97-102 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Science ) The synthesis of water-dispersible amino-acid-protected gold nanoparticles by the spontaneous redn. of aq. chloroaurate ions by tryptophan is described. Water-dispersible gold nanoparticles may also be obtained by the sequential synthesis of the gold nanoparticles by borohydride redn. of chloroauric acid followed by capping with tryptophan. Comparison of the proton NMR spectroscopic signatures from the tryptophan-protected gold nanoparticles obtained by the two processes indicated that the indole group in tryptophan is responsible for redn. of the aq. chloroaurate ions. The redn. of the metal ions is accompanied by oxidative polymn. of the indole group of the tryptophan mols. and, consequently, some degree of crosslinking of the gold nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXptlCgt74%253D&md5=fae229bad885f957fc499e5367ccb6fc
- 21 Selvakannan, P. R. ; Mandal, S. ; Phadtare, S. ; Pasricha, R. ; Sastry, M. Capping of Gold Nanoparticles by the Amino Acid Lysine Renders Them Water-Dispersible . Langmuir 2003 , 19 , 3545 – 3549 , DOI: 10.1021/la026906v 21 Capping of Gold Nanoparticles by the Amino Acid Lysine Renders Them Water-Dispersible Selvakannan, P. R.; Mandal, Saikat; Phadtare, Sumant; Pasricha, Renu; Sastry, Murali Langmuir ( 2003 ), 19 ( 8 ), 3545-3549 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Capping aq. gold nanoparticles with the amino acid lysine stabilizes the particles in soln. electrostatically and also renders them water-dispersible. The lysine-capped gold nanoparticles may be obtained in the form of a dry powder after evapn. of the aq. component, this powder being extremely stable in air and readily redispersible in water. Development of protocols for the synthesis of water-dispersible nanoparticles has immense application in a variety of fields, but clearly more so in biorelated areas such as biolabeling and biosensing. The amino acid protected gold nanoparticles have been characterized by UV-vis spectroscopy, TEM, thermogravimetric anal. (TGA), and proton NMR spectroscopy. To the best of the authors' knowledge, this is the first report on use of an amino acid for stabilizing and rendering gold nanoparticles water-dispersible. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhslSlt7k%253D&md5=5c2a9c49e39cb7e73e0de4b4ae98778a
- 22 Wangoo, N. ; Bhasin, K. K. ; Mehta, S. K. ; Suri, C. R. Synthesis and Capping of Water-Dispersed Gold Nanoparticles by an Amino Acid: Bioconjugation and Binding Studies . J. Colloid Interface Sci. 2008 , 323 , 247 – 254 , DOI: 10.1016/j.jcis.2008.04.043 22 Synthesis and capping of water-dispersed gold nanoparticles by an amino acid: Bioconjugation and binding studies Wangoo, Nishima; Bhasin, K. K.; Mehta, S. K.; Suri, C. Raman Journal of Colloid and Interface Science ( 2008 ), 323 ( 2 ), 247-254 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Inc. ) The authors report a novel strategy for the synthesis of aq. stable, carboxylated Au nanoparticles (GNPs) by using glutamic acid as the reducing agent. The ratio of chloroaurate ions, AuCl- 4 to glutamic acid was optimized in the reaction medium to obtain monodispersed GNPs. Glutamic acid reduced Au nanoparticles were characterized by UV-visible, FTIR, dynamic light scattering and TEM, which demonstrated high stability in aq. soln. over a period of time indicating stabilization via surface-bound amino acid. Functionalized nanoparticles were conjugated with protein mols. through electrostatic attraction between the surface-terminated neg. charged carboxylate groups (-COO-) of glutamic acid and the pos. charged amino groups (-NH+3) of the protein. The conjugation efficiency of the GNP:protein conjugates was confirmed qual. and quant. through gel electrophoresis and crit. flocculation concn. anal. The interaction between functionalized GNPs with protein mols. was studied using fluorescence spectroscopy showing the fluorescence quenching of the tryptophan residues of protein mols. after conjugation. CD studies of the conjugates confirmed that the protein undergoes a more flexible conformational state on the boundary surface of GNPs after conjugation. There was substantial conformational transition from α-helix to β-sheet structure after conjugation of protein to GNPs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmvVemu7w%253D&md5=382cd2df4457414516d1214237fce899
- 23 Malik, P. ; Shankar, R. ; Malik, V. ; Sharma, N. ; Mukherjee, T. K. Green Chemistry Based Benign Routes for Nanoparticle Synthesis . J. Nanopart. 2014 , 2014 , 1 – 14 , DOI: 10.1155/2014/302429 There is no corresponding record for this reference.
- 24 Zaheer, Z. ; Malik, M. A. ; Al-Nowaiser, F. M. ; Khan, Z. Preparation of Silver Nanoparticles Using Tryptophan and Its Formation Mechanism . Colloids Surf., B 2010 , 81 , 587 – 592 , DOI: 10.1016/j.colsurfb.2010.08.001 24 Preparation of silver nanoparticles using tryptophan and its formation mechanism Zaheer, Zoya; Malik, Maqsood Ahmad; Al-Nowaiser, F. M.; Khan, Zaheer Colloids and Surfaces, B: Biointerfaces ( 2010 ), 81 ( 2 ), 587-592 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) A non-toxic route was used for the prepn. of silver nanoparticles using tryptophan (Trp) as reducing/stabilizing agent in the presence of cetyltrimethyl ammonium bromide (CTAB). Role of water sol. neutral polymer poly(vinylpyrrolidone) (PVP) was studied on the growth of yellow color silver nanoparticle formation. The synthesized nanostructures were characterized by UV-Visible absorption spectroscopy, transmission electron microscopy (TEM) by observing the size and distribution of silver nanoparticles. As the reaction proceeded, particles grew up to about 10 and 20 nm in the presence and absence of PVP, resp., as detd. by TEM. The formed nanoparticles showed the highest absorption plasmon band at 425 nm. Rate of silver sol formation increases with the [Trp], [CTAB] and [PVP], reaching a limiting value and then decreases with the increase in concns. of these reagents. It was obsd. that nanoparticles are spherical, aggregated and polydispersed in the absence and presence of PVP, resp. On the basis of kinetic data, a suitable mechanism is proposed and discussed for the silver sol formation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtFynsb7I&md5=eba869ddf2647f64267829fcfce27759
- 25 Chandra, A. ; Singh, M. Amino Acid-Functionalized Silver Nanoparticles as Green Catalyst for Methylene Blue Reduction . International Scholarly and Scientific Research & Innovation 2015 , 9 , 1211 – 1217 , DOI: 10.5281/zenodo.1110580 There is no corresponding record for this reference.
- 26 Roy, M. ; Mukherjee, P. ; Mandal, B. P. ; Sharma, R. K. ; Tyagi, A. K. ; Kale, S. P. Biomimetic Synthesis of Nanocrystalline Silver Sol Using Cysteine: Stability Aspects and Antibacterial Activities . RSC Adv. 2012 , 2 , 6496 – 6503 , DOI: 10.1039/c2ra00785a 26 Biomimetic synthesis of nanocrystalline silver sol using cysteine: stability aspects and antibacterial activities Roy, Mainak; Mukherjee, Poulomi; Mandal, Balaji P.; Sharma, Rajendra K.; Tyagi, Avesh K.; Kale, Sharad P. RSC Advances ( 2012 ), 2 ( 16 ), 6496-6503 CODEN: RSCACL ; ISSN: 2046-2069 . ( Royal Society of Chemistry ) The study reports the development of a simple, environmentally benign green chem. route to produce stable silver nanoparticle (Ag-np) sols with excellent antibacterial properties under ambient conditions. The method involves the room temp. redn. of AgNO3 by cysteine (aq) and requires no addnl. capping/stabilizing agent. It essentially mimics the redox reaction that takes place during incubation of the cell-free ext. from Trichoderma asperellum in the presence of AgNO3 (aq) (P. Mukherjee, M. Roy, B. P. Mandal, G. K. Dey, P. K. Mukherjee, J. Ghatak, A. K. Tyagi and S. P. Kale, Nanotechnol., 2008, 19, 075103), wherein cysteine, a biomol. present in the fungal ext., acts as a potential reducing agent. Addnl., cysteine acts as a capping mol. in the present case. Formation of Ag-nps was evidenced from UV-Vis, TEM, XRD and EDS studies. The stability of Ag sols was shown to depend strongly on the concn. of cysteine relative to that of AgNO3. Sols obtained by reacting 0.1 mM of cysteine with 1 mM of AgNO3 remained stable for more than one month at 24 °C. The role of cysteine as capping mol. and the possible modes of its linkages with Ag-nps was studied by FT-IR, XPS and Raman spectroscopy. Bonding of Ag with either or all the 3, thiolate, amino and carboxylate groups of the cysteine mol. via stable PH configuration is believed to have resulted in the stabilization of the Ag-nps. Antibacterial activity of the cysteine capped Ag sol was studied along with that of the Ag sol obtained by fungal route. Both the sols exhibited excellent and comparable efficacies as bactericidal agents against gram neg. bacteria E. coli BW (25113), with one of the lowest min. inhibitory concn. (MIC) and min. bactericidal concn. (MBC) values published so far. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtVeisLrM&md5=c9fbf7c3402404061b659a4534e0bf45
- 27 Csapó, E. ; Patakfalvi, R. ; Hornok, V. ; Tóth, L. T. ; Sipos, Á. ; Szalai, A. ; Csete, M. ; Dékány, I. Effect of PH on Stability and Plasmonic Properties of Cysteine-Functionalized Silver Nanoparticle Dispersion . Colloids Surf., B 2012 , 98 , 43 – 49 , DOI: 10.1016/j.colsurfb.2012.03.036 27 Effect of pH on stability and plasmonic properties of cysteine-functionalized silver nanoparticle dispersion Csapo, Edit; Patakfalvi, Rita; Hornok, Viktoria; Toth, Laszlo Tamas; Sipos, Aron; Szalai, Aniko; Csete, Maria; Dekany, Imre Colloids and Surfaces, B: Biointerfaces ( 2012 ), 98 ( ), 43-49 CODEN: CSBBEQ ; ISSN: 0927-7765 . ( Elsevier B.V. ) Citrate-stabilized spherical silver nanoparticles (Ag NPs) with d = 8.25 ± 1.25 nm diam. were prepd. and functionalized with L-cysteine (Cys) in aq. dispersion. The nanosilver-cysteine interactions have been studied by Raman and 1H NMR spectroscopy. The effect of pH on stability of biofunctionalized Ag NPs was studied. The cysteine-capped nanosilver dispersions remain stable at higher pH (pH > 7), while the degree of aggregation increased as the pH decreased. Below pH ∼7, the characteristic surface plasmon band of bare silver nanoparticles was back-shifted from λmeasuredbareAgNP = 391nm to λmeasured1 = 387-391nm, while the presence of a new band at λmeasured2 = 550-600nm was also obsd. depending on pH. Finite element method (FEM) was applied to numerically compute the absorption spectra of aq. dispersions contg. bare and cysteine-functionalized Ag NPs at different pH. Both the dynamic light scattering (DLS) measurements, Zeta potential values and the transmission electron microscopic (TEM) images confirmed the authors' supposition. Namely, electrostatic interaction arose between the deprotonated carboxylate (COO-) and protonated amino groups (NH3 +) of the amino acid resulting in crosslinking network of the Ag NPs between pH ∼3 and 7. If the pH is measurable .ltorsim.3, parallel with the protonation of citrate and L-cysteine mols. the connection of the particles via L-cysteine is partly decompd. resulting in decrease of second plasmon band intensity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XpsVKqsbc%253D&md5=f339cd063f59885d4e0779f08d498d75
- 28 Selvakannan, P. R. ; Swami, A. ; Srisathiyanarayanan, D. ; Shirude, P. S. ; Pasricha, R. ; Mandale, A. B. ; Sastry, M. Synthesis of aqueous Au core– Ag shell nanoparticles using tyrosine as a pH-dependent reducing agent and assembling phase-transferred silver nanoparticles at the air- water interface . Langmuir 2004 , 20 , 7825 – 7836 , DOI: 10.1021/la049258j 28 Synthesis of Aqueous Au Core-Ag Shell Nanoparticles Using Tyrosine as a pH-Dependent Reducing Agent and Assembling Phase-Transferred Silver Nanoparticles at the Air-Water Interface Selvakannan, PR.; Swami, Anita; Srisathiyanarayanan, D.; Shirude, Pravin S.; Pasricha, Renu; Mandale, Anandrao B.; Sastry, Murali Langmuir ( 2004 ), 20 ( 18 ), 7825-7836 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) We demonstrate that the amino acid tyrosine is an excellent reducing agent under alk. conditions and may be used to reduce Ag+ ions to synthesize stable silver nanoparticles in water. The tyrosine-reduced silver nanoparticles may be sepd. out as a powder that is readily redispersible in water. The silver ion redn. at high pH occurs due to ionization of the phenolic group in tyrosine that is then capable of reducing Ag+ ions and is in turn converted to a semi-quinone structure. These silver nanoparticles can easily be transferred to chloroform contg. the cationic surfactant octadecylamine by an electrostatic complexation process. The now hydrophobic silver nanoparticles may be spread on the surface of water and assembled into highly ordered, linear superstructures that could be transferred as multilayers onto suitable supports by the versatile Langmuir-Blodgett technique. Further, tyrosine mols. bound to the surface of Au nanoparticles through amine groups in the amino acid may be used to selectively reduce silver ions at high pH on the surface of the Au nanoparticles, thus leading to a simple strategy for realizing phase-pure Au core-Ag shell nanostructures. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXls1Kkt74%253D&md5=ec3102944fcb4dc19693afd5f1c26574
- 29 Iravani, S. Green Synthesis of Metal Nanoparticles Using Plants . Green Chem. 2011 , 13 , 2638 – 2650 , DOI: 10.1039/c1gc15386b 29 Green synthesis of metal nanoparticles using plants Iravani, Siavash Green Chemistry ( 2011 ), 13 ( 10 ), 2638-2650 CODEN: GRCHFJ ; ISSN: 1463-9262 . ( Royal Society of Chemistry ) A review. In recent years, the development of efficient green chem. methods for synthesis of metal nanoparticles has become a major focus of researchers. They have investigated in order to find an eco-friendly technique for prodn. of well-characterized nanoparticles. One of the most considered methods is prodn. of metal nanoparticles using organisms. Among these organisms plants seem to be the best candidates and they are suitable for large-scale biosynthesis of nanoparticles. Nanoparticles produced by plants are more stable and the rate of synthesis is faster than in the case of microorganisms. Moreover, the nanoparticles are more various in shape and size in comparison with those produced by other organisms. The advantages of using plant and plant-derived materials for biosynthesis of metal nanoparticles have interested researchers to investigate mechanisms of metal ions uptake and bioredn. by plants, and to understand the possible mechanism of metal nanoparticle formation in plants. In this review, most of the plants used in metal nanoparticle synthesis are shown. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVSksb3N&md5=d8fe8cd73ddbf03826145cc6c075b6c9
- 30 Natsuki, J. ; Natsuki, T. ; Hashimoto, Y. A Review of Silver Nanoparticles: Synthesis Methods, Properties and Applications . Int. J. Mater. Sci. Appl. 2015 , 4 , 325 – 332 , DOI: 10.11648/j.ijmsa.20150405.17 30 A review of silver nanoparticles: synthesis methods, properties and applications Natsuki, Jun; Natsuki, Toshiaki; Hashimoto, Yoshio International Journal of Materials Science and Applications ( 2015 ), 4 ( 5 ), 325-332 CODEN: IJMSM7 ; ISSN: 2327-2643 . ( Science Publishing Group ) In recent years, nanoparticles of noble metals such as gold, silver and palladium have drawn immense attention due to the wide range of new applications in various fields of industry. Particularly, silver nanoparticles have significant interest in medical applications such as very effective antibacterial agents without the toxic effects, and industry application such as inkjet inks contg. well uniform dispersions of nano-sized silver particles that are useful for producing electronic circuits. It is important that the silver nanoparticles require not only the particles to be of nano-size, but also synthesis of the nanoparticles to be produced easily and at low cost. Over the past few decades, many synthetic methods of silver nanoparticles have been studied. This paper aims to review different synthesis routes of silver nanoparticles and their applications. In particular, we mainly present several chem. approaches to prepg. silver nanoparticles and their properties as well as applications based on our recent studies. The focus is on effective and efficient synthesis of pure colloidal silver nanoparticles with high elec. cond. and their potential application. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXlsFyhsLs%253D&md5=81c282bc341cb10cf918df1193cf39c3
- 31 Rauwel, P. ; Küünal, S. ; Ferdov, S. ; Rauwel, E. A review on the green synthesis of silver nanoparticles and their morphologies studied via TEM . Adv. Mater. Sci. Eng. 2015 , 2015 , 1 – 9 , DOI: 10.1155/2015/682749 There is no corresponding record for this reference.
- 32 Siddiqi, K. S. ; Husen, A. ; Rao, R. A. A Review on Biosynthesis of Silver Nanoparticles and Their Biocidal Properties . J. Nanobiotechnol. 2018 , 16 , 1 – 28 , DOI: 10.1186/s12951-018-0334-5 There is no corresponding record for this reference.
- 33 Marambio-Jones, C. ; Hoek, E. M. V. A Review of the Antibacterial Effects of Silver Nanomaterials and Potential Implications for Human Health and the Environment . J. Nanopart. Res. 2010 , 12 , 1531 – 1551 , DOI: 10.1007/s11051-010-9900-y 33 A review of the antibacterial effects of silver nanomaterials and potential implications for human health and the environment Marambio-Jones, Catalina; Hoek, Eric M. V. Journal of Nanoparticle Research ( 2010 ), 12 ( 5 ), 1531-1551 CODEN: JNARFA ; ISSN: 1388-0764 . ( Springer ) Here, we present a review of the antibacterial effects of silver nanomaterials, including proposed antibacterial mechanisms and possible toxicity to higher organisms. For purpose of this review, silver nanomaterials include silver nanoparticles, stabilized silver salts, silver-dendrimer, polymer and metal oxide composites, and silver-impregnated zeolite and activated carbon materials. While there is some evidence that silver nanoparticles can directly damage bacteria cell membranes, silver nanomaterials appear to exert bacteriocidal activity predominantly through release of silver ions followed (individually or in combination) by increased membrane permeability, loss of the proton motive force, inducing de-energization of the cells and efflux of phosphate, leakage of cellular content, and disruption DNA replication. Eukaryotic cells could be similarly impacted by most of these mechanisms and, indeed, a small but growing body of literature supports this concern. Most antimicrobial studies are performed in simple aquatic media or cell culture media without proper characterization of silver nanomaterial stability (aggregation, dissoln., and re-pptn.). Silver nanoparticle stability is governed by particle size, shape, and capping agents as well as soln. pH, ionic strength, specific ions and ligands, and org. macromols.-all of which influence silver nanoparticle stability and bioavailability. Although none of the studies reviewed definitively proved any immediate impacts to human health or the environment by a silver nanomaterial contg. product, the entirety of the science reviewed suggests some caution and further research are warranted given the already widespread and rapidly growing use of silver nanomaterials. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsFOrur0%253D&md5=6aae4aee458d3e417b41f58f98080449
- 34 Kulkarni, S. K. Nanotechnology: Principles and Practices ; Springer International Publishing , 2015 . There is no corresponding record for this reference.
- 35 Tran, Q. H. ; Nguyen, V. Q. ; Le, A.-T. Silver Nanoparticles: Synthesis, Properties, Toxicology, Applications and Perspectives . Advances in Natural Sciences: Nanoscience and Nanotechnology 2013 , 4 , 033001 , DOI: 10.1088/2043-6262/4/3/033001 35 Silver nanoparticles: synthesis, properties, toxicology, applications and perspective Tran, Quang Huy; Nguyen, Van Quy; Le, Anh-Tuan Advances in Natural Sciences: Nanoscience and Nanotechnology ( 2013 ), 4 ( 3 ), 033001 CODEN: ANSNCK ; ISSN: 2043-6262 . ( IOP Publishing Ltd. ) A review. In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H5N1), diarrhea (Escherichia coli), cholera (-Vibrio cholera), etc throughout the world. The comprehensive treatments of environments contg. infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicol. considerations of Ag-NPs to humans and ecol. are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVCjsbw%253D&md5=13357b298b4cb04ededfdc2083fca9d0
- 36 Argueta Figueroa, L. ; Arenas-Arrocena ; Ma, C. ; Díaz-Herrera, A. P. ; García-Benítez, S. V. ; García-Contreras, R. Propiedades Antimicrobianas y Citotóxicas de Un Adhesivo de Uso Ortodóncico Adicionado Con Nanopartículas de Plata . Mundo Nano. Revista Interdisciplinaria en Nanociencias y Nanotecnología 2018 , 12 , 1 , DOI: 10.22201/ceiich.24485691e.2019.22.62550 There is no corresponding record for this reference.
- 37 Xing, M. ; Ge, L. ; Wang, M. ; Li, Q. ; Li, X. ; Ouyang, J. Nanosilver Particles in Medical Applications: Synthesis, Performance, and Toxicity . Int. J. Nanomed. 2014 , 9 , 2399 – 2407 , DOI: 10.2147/IJN.S55015 There is no corresponding record for this reference.
- 38 Cheng, G. ; Dai, M. ; Ahmed, S. ; Hao, H. ; Wang, X. ; Yuan, Z. Antimicrobial Drugs in Fighting against Antimicrobial Resistance . Frontiers in Microbiology 2016 , DOI: 10.3389/fmicb.2016.00470 There is no corresponding record for this reference.
- 39 Raveendran, P. ; Fu, J. ; Wallen, S. L. Completely “Green” Synthesis and Stabilization of Metal Nanoparticles . J. Am. Chem. Soc. 2003 , 125 , 13940 – 13941 , DOI: 10.1021/ja029267j 39 Completely green synthesis and stabilization of metal nanoparticles Raveendran, Poovathinthodiyil; Fu, Jie; Wallen, Scott L. Journal of the American Chemical Society ( 2003 ), 125 ( 46 ), 13940-13941 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A completely green synthetic method for producing silver nanoparticles is introduced. The process is simple, environmentally benign and quite efficient. By gentle heating of an aq. starch soln. contg. silver nitrate and glucose, relatively monodisperse, starched silver nanoparticles are produced. β-D-Glucose serves as the green reducing agent, while starch serves as the stabilization agent. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXot12ms7k%253D&md5=924330e7ba08a32194f54a1875c25898
- 40 Mann, S. Biomineralization and biomimetic materials chemistry. Biomimetic materials chemistry ; Mann, S. , Ed.; VCH Publishers, Inc. : New York, USA , 1996 , 47 . There is no corresponding record for this reference.
- 41 Zhang, X. F. ; Liu, Z. G. ; Shen, W. ; Gurunathan, S. Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches . Int. J. Mol. Sci. 2016 , 17 , 1534 , DOI: 10.3390/ijms17091534 41 Silver nanoparticles: synthesis, characterization, properties, applications, and therapeutic approaches Zhang, Xi-Feng; Liu, Zhi-Guo; Shen, Wei; Gurunathan, Sangiliyandi International Journal of Molecular Sciences ( 2016 ), 17 ( 9 ), 1534/1-1534/34 CODEN: IJMCFK ; ISSN: 1422-0067 . ( MDPI AG ) Recent advances in nanoscience and nanotechnol. radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in biomedical applications. AgNPs play an important role in nanoscience and nanotechnol., particularly in nanomedicine. Although several noble metals have been used for various purposes, AgNPs have been focused on potential applications in cancer diagnosis and therapy. In this review, we discuss the synthesis of AgNPs using phys., chem., and biol. methods. We also discuss the properties of AgNPs and methods for their characterization. More importantly, we extensively discuss the multifunctional bio-applications of AgNPs; for example, as antibacterial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anti-cancer agents, and the mechanism of the anti-cancer activity of AgNPs. In addn., we discuss therapeutic approaches and challenges for cancer therapy using AgNPs. Finally, we conclude by discussing the future perspective of AgNPs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvF2qs7rM&md5=e40f79b90c36beb092c677d11d137fdd
- 42 Arokiyaraj, S. ; Arasu, M. V. ; Vincent, S. ; Prakash, N. U. ; Choi, S. H. ; Oh, Y. K. ; Choi, K. C. ; Kim, K. H. Rapid Green Synthesis of Silver Nanoparticles from Chrysanthemum Indicum Land Its Antibacterial and Cytotoxic Effects: An in Vitro Study . Int. J. Nanomed. 2014 , 9 , 379 – 388 , DOI: 10.2147/IJN.S53546 There is no corresponding record for this reference.
- 43 Maruyama, T. ; Fujimoto, Y. ; Maekawa, T. Synthesis of Gold Nanoparticles Using Various Amino Acids . J. Colloid Interface Sci. 2015 , 447 , 254 – 257 , DOI: 10.1016/j.jcis.2014.12.046 43 Synthesis of gold nanoparticles using various amino acids Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya Journal of Colloid and Interface Science ( 2015 ), 447 ( ), 254-257 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier B.V. ) Gold nanoparticles (4-7 nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl-4 soln. with an amino acid at 80°C for 20 min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solns. varied with the amino acids used for the redn. L-Histidine was used as a reducing agent, and the effects of the synthesis conditions on the gold nanoparticles were investigated. The His and AuCl-4 concns. affected the size of the gold nanoparticles and their aggregates. The pH of the reaction soln. also affected the reaction yields and the shape of the gold nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVKgtQ%253D%253D&md5=abc8ab54b03371d9f2bcb4e4228ebc69
- 44 Mu, X. ; Qi, L. ; Qiao, J. ; Ma, H. One-Pot Synthesis of Tyrosine-Stabilized Fluorescent Gold Nanoclusters and Their Application as Turn-on Sensors for Al3+ Ions and Turn-off Sensors for Fe3+ Ions . Anal. Methods 2014 , 6 , 6445 – 6451 , DOI: 10.1039/C4AY01137F 44 One-pot synthesis of tyrosine-stabilized fluorescent gold nanoclusters and their application as turn-on sensors for Al3+ ions and turn-off sensors for Fe3+ ions Mu, Xiaoyu; Qi, Li; Qiao, Juan; Ma, Huimin Analytical Methods ( 2014 ), 6 ( 16 ), 6445-6451 CODEN: AMNEGX ; ISSN: 1759-9679 . ( Royal Society of Chemistry ) The simplicity of the one-pot green synthesis routine and the capability of surface modification of various bioactive mols. make gold nanoclusters (Au NCs) highly suitable as scaffolds for the construction of novel chem. and biol. sensors. In this work, we report a novel strategy to prep. amino acid stabilized fluorescent Au NCs via a green one-pot process. The obtained Au NCs possessed light green fluorescence with max. emission at 498 nm and their quantum yield (QY) was evaluated to be 1.68%. Subsequently, the developed fluorescent Au NC biosensor allowed sensitive and selective detection of Fe3+ ions based on fluorescence quenching with a detection limit of 0.2 μM and Al3+ ions based on enhanced fluorescence with a detection limit of 0.3 μM, resp. Furthermore, we testified the feasibility of applying this fluorescent probe for real sample anal. through the detection of Al3+ ions and Fe3+ ions in lake water, pond water and tap water. These results indicated that the as-prepd. Au NCs had great potential to be developed as the favorable sensor for detection of metal ions in real samples. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFWitrzP&md5=4ebf006d4e70bf5dda41182fac6399ae
- 45 Dubey, K. ; Anand, B. G. ; Badhwar, R. ; Bagler, G. ; Navya, P. N. ; Daima, H. K. ; Kar, K. Tyrosine- and Tryptophan-Coated Gold Nanoparticles Inhibit Amyloid Aggregation of Insulin . Amino Acids 2015 , 47 , 2551 – 2560 , DOI: 10.1007/s00726-015-2046-6 45 Tyrosine- and tryptophan-coated gold nanoparticles inhibit amyloid aggregation of insulin Dubey, Kriti; Anand, Bibin G.; Badhwar, Rahul; Bagler, Ganesh; Navya, P. N.; Daima, Hemant Kumar; Kar, Karunakar Amino Acids ( 2015 ), 47 ( 12 ), 2551-2560 CODEN: AACIE6 ; ISSN: 0939-4451 . ( Springer-Verlag GmbH ) Here, we have strategically synthesized stable gold (AuNPsTyr, AuNPsTrp) and silver (AgNPsTyr) nanoparticles which are surface functionalized with either tyrosine or tryptophan residues and have examd. their potential to inhibit amyloid aggregation of insulin. Inhibition of both spontaneous and seed-induced aggregation of insulin was obsd. in the presence of AuNPsTyr, AgNPsTyr, and AuNPsTrp nanoparticles. These nanoparticles also triggered the disassembly of insulin amyloid fibrils. Surface functionalization of amino acids appears to be important for the inhibition effect since isolated tryptophan and tyrosine mols. did not prevent insulin aggregation. Bioinformatics anal. predicts involvement of tyrosine in H-bonding interactions mediated by its C=O, -NH2, and arom. moiety. These results offer significant opportunities for developing nanoparticle-based therapeutics against diseases related to protein aggregation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht1SgtbfE&md5=05ac4ada9be9c9fa7694d60cdfa597c1
- 46 Joshi, H. ; Shirude, P. S. ; Bansal, V. ; Ganesh, K. N. ; Sastry, M. Isothermal Titration Calorimetry Studies on the Binding of Amino Acids to Gold Nanoparticles . J. Phys. Chem. B 2004 , 108 , 11535 – 11540 , DOI: 10.1021/jp048766z 46 Isothermal titration calorimetry studies on the binding of amino acids to gold nanoparticles Joshi, Hrushikesh; Shirude, Pravin S.; Bansal, Vipul; Ganesh, K. N.; Sastry, Murali Journal of Physical Chemistry B ( 2004 ), 108 ( 31 ), 11535-11540 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Isothermal titrn. calorimetry (ITC) is a powerful and highly sensitive technique commonly used to study interactions between biomols. in dil. aq. solns., both from thermodn. and kinetics points of view. In this report, we show that ITC may be used to follow the binding of ligands such as amino acids to the surface of inorg. materials such as gold nanoparticles. More specifically, we have studied the binding of one basic amino acid, lysine, and an acidic amino acid, aspartic acid, with aq. gold nanoparticles at physiol. pH. Strong binding of aspartic acid with the gold nanoparticles under these conditions is indicated by ITC, while weak binding was obsd. in the case of lysine. The differences in binding are attributed to protonation of amine groups in lysine at physiol. pH (pI ∼ 9.4) while they are not protonated for aspartic acid (pI ∼ 2.77). That this is the likely mechanism is indicated by the ITC measurement of binding of lysine with nanogold at pH 11 (when the amine groups are not protonated). The binding of the amino acids with gold nanoparticles has been validated with other techniques such as gel electrophoresis and x-ray photoemission spectroscopy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXltl2lsbk%253D&md5=d59c01679f49473373fb26999cd2fb63
- 47 Wang, X. ; Li, Y. Synthesis and Characterization of Lanthanide Hydroxide Single-Crystal Nanowires . Angew. Chem. 2002 , 114 , 4984 – 4987 , DOI: 10.1002/ange.200290048 There is no corresponding record for this reference.
- 48 Mai, H. X. ; Sun, L. D. ; Zhang, Y. W. ; Si, R. ; Feng, W. ; Zhang, H. P. ; Liu, H. C. ; Yan, C. H. Shape-Selective Synthesis and Oxygen Storage Behavior of Ceria Nanopolyhedra, Nanorods, and Nanocubes . J. Phys. Chem. B 2005 , 109 , 24380 – 24385 , DOI: 10.1021/jp055584b 48 Shape-Selective Synthesis and Oxygen Storage Behavior of Ceria Nanopolyhedra, Nanorods, and Nanocubes Mai, Hao-Xin; Sun, Ling-Dong; Zhang, Ya-Wen; Si, Rui; Feng, Wei; Zhang, Hong-Peng; Liu, Hai-Chao; Yan, Chun-Hua Journal of Physical Chemistry B ( 2005 ), 109 ( 51 ), 24380-24385 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Single-cryst. and uniform nanopolyhedra, nanorods, and nanocubes of cubic CeO2 were selectively prepd. by a hydrothermal method at temps. in the range of 100-180 °C under different NaOH concns., using Ce(NO3)3 as the cerium source. According to high-resoln. transmission electron microscopy, they have different exposed crystal planes: {111} and {100} for polyhedra, {110} and {100} for rods, and {100} for cubes. During the synthesis, the formation of hexagonal Ce(OH)3 intermediate species and their transformation into CeO2 at elevated temp., together with the base concn., have been demonstrated as the key factors responsible for the shape evolution. Oxygen storage capacity (OSC) measurements at 400 °C revealed that the oxygen storage takes place both at the surface and in the bulk for the as-obtained CeO2 nanorods and nanocubes, but is restricted at the surface for the nanopolyhedra just like the bulk one, because the {100}/{110}-dominated surface structures are more reactive for CO oxidn. than the {111}-dominated one. This result suggests that high OSC materials might be designed and obtained by shape-selective synthetic strategy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1Omtr3E&md5=e813a9265ad2ef9f6cde8471dad765b1
- 49 Kaneko, K. ; Inoke, K. ; Freitag, B. ; Hungria, A. B. ; Midgley, P. A. ; Hansen, T. W. ; Zhang, J. ; Ohara, S. ; Adschiri, T. Structural and Morphological Characterization of Cerium Oxide Nanocrystals Prepared by Hydrothermal Synthesis . Nano Lett. 2007 , 7 ( 2 ), 421 – 425 , DOI: 10.1021/nl062677b 49 Structural and Morphological Characterization of Cerium Oxide Nanocrystals Prepared by Hydrothermal Synthesis Kaneko, Kenji; Inoke, Koji; Freitag, Bert; Hungria, Ana B.; Midgley, Paul A.; Hansen, Thomas W.; Zhang, Jing; Ohara, Satoshi; Adschiri, Tadafumi Nano Letters ( 2007 ), 7 ( 2 ), 421-425 CODEN: NALEFD ; ISSN: 1530-6984 . ( American Chemical Society ) Colloidal cerium oxide (CeO2) nanocrystals prepd. by hydrothermal synthesis were characterized by high-resoln. transmission electron microscopy (HRTEM) and three-dimensional electron tomog. (3D-ET). HRTEM images of individual CeO2 nanocrystals were then simulated by Blochwave and multislice simulations to det. the at. arrangement and terminating atoms. The edge length distributions were between 5.0 and 8.0 nm with an av. edge length of 6.7 nm. The HRTEM images showed that the CeO2 particles were slightly truncated revealing {220} facets. 3D-ET revealed that the CeO2 nanocrystals exposed predominantly {200} cubic facets. The nanocrystals were truncated at the corners exposing {111} octahedral facets and at the edges {220} dodecahedral facets. Furthermore, 3D-ET revealed the presence of some tetragonal-shaped CeO2 nanocrystals. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXktF2ktQ%253D%253D&md5=330852543d80c9633078c94966d87d5e
- 50 Yang, S. ; Gao, L. Controlled Synthesis and Self-Assembly of CeO 2 Nanocubes . J. Am. Chem. Soc. 2006 , 128 , 9330 – 9331 , DOI: 10.1021/ja063359h 50 Controlled Synthesis and Self-Assembly of CeO2 Nanocubes Yang, Songwang; Gao, Lian Journal of the American Chemical Society ( 2006 ), 128 ( 29 ), 9330-9331 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) CeO2 nanocubes (and nanorods) enclosed by six {200} planes with controlled sizes have been prepd. through a facile one-pot method. The nanocubes have a strong tendency to assemble into 2D and 3D arrays with regular patterns on a substrate, which is probably driven by the dipole-dipole interaction of polar {200} planes. The possible formation mechanism of the nanocubes has been put forward as the oriented aggregation mediated precursor growth. It is possible to use the synthesized nanocubes as building blocks to achieve {200}-perfect-oriented monolayers or thickness-controlled films and to apply the preparative method in the incorporation of heterogeneous atoms or nanoparticles for semiconductor doping or heterogeneous nanostructures. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmsVeks7o%253D&md5=696b56593c4b1e70f41f8366d5549611
- 51 Qian, L. ; Zhu, J. ; Du, W. ; Qian, X. Solvothermal Synthesis, Electrochemical and Photocatalytic Properties of Monodispersed CeO2 Nanocubes . Mater. Chem. Phys. 2009 , 115 , 835 – 840 , DOI: 10.1016/j.matchemphys.2009.02.047 51 Solvothermal synthesis, electrochemical and photocatalytic properties of monodispersed CeO2 nanocubes Qian, Liwu; Zhu, Jun; Du, Weimin; Qian, Xuefeng Materials Chemistry and Physics ( 2009 ), 115 ( 2-3 ), 835-840 CODEN: MCHPDR ; ISSN: 0254-0584 . ( Elsevier B.V. ) Cubic-like CeO2 nanocrystals were prepd. through an improved-toluene solvothermal process using hexadecylamine (HAD) as a capping agent and CeCl3.7H2O as a precursor at 180° for 24 h. These nanocubes are ≈10 nm in size, and have a tendency to assemble into 2D superstructure. The obtained samples were characterized by x-ray powder diffraction (XRD) and TEM. The water content, the concn. of ligand, and kinds of aliph. amine played important roles in the formation of the novel morphol. A possible formation mechanism was proposed based on the controlling reaction parameters. The electrochem. and photocatalytic properties of the as-prepd. samples exhibited the size/shape-dependent properties and potential applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXltVynsrw%253D&md5=977753f15f7f4af99a6ba986c3c3f0da
- 52 Ke, J. ; Xiao, J. W. ; Zhu, W. ; Liu, H. ; Si, R. ; Zhang, Y. W. ; Yan, C. H. Dopant-Induced Modification of Active Site Structure and Surface Bonding Mode for High-Performance Nanocatalysts: CO Oxidation on Capping-Free (110)-Oriented CeO2:Ln (Ln = La-Lu) Nanowires . J. Am. Chem. Soc. 2013 , 135 , 15191 – 15200 , DOI: 10.1021/ja407616p 52 Dopant-Induced Modification of Active Site Structure and Surface Bonding Mode for High-Performance Nanocatalysts: CO Oxidation on Capping-free (110)-oriented CeO2:Ln (Ln = La-Lu) Nanowires Ke, Jun; Xiao, Jia-Wen; Zhu, Wei; Liu, Haichao; Si, Rui; Zhang, Ya-Wen; Yan, Chun-Hua Journal of the American Chemical Society ( 2013 ), 135 ( 40 ), 15191-15200 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) Active center engineering at at. level is a grand challenge for catalyst design and optimization in many industrial catalytic processes. Exploring new strategies to delicately tailor the structures of active centers and bonding modes of surface reactive intermediates for nanocatalysts is crucial to high-efficiency nanocatalysis that bridges heterogeneous and homogeneous catalysis. Here we demonstrate a robust approach to tune the CO oxidn. activity over CeO2 nanowires (NWs) through the modulation of the local structure and surface state around LnCe' defect centers by doping other lanthanides (Ln), based on the continuous variation of the ionic radius of lanthanide dopants caused by the lanthanide contraction. Homogeneously doped (110)-oriented CeO2:Ln NWs with no residual capping agents were synthesized by controlling the redox chem. of Ce-(III)/Ce-(IV) in a mild hydrothermal process. The CO oxidn. reactivity over CeO2:Ln NWs was dependent on the Ln dopants, and the reactivity reached the max. in turnover rates over Nd-doped samples. On the basis of the results obtained from combined experimentations and d. functional theory simulations, the decisive factors of the modulation effect along the lanthanide dopant series were deduced as surface oxygen release capability and the bonding configuration of the surface adsorbed species (i.e., carbonates and bicarbonates) formed during catalytic process, which resulted in the existence of an optimal doping effect from the lanthanide with moderate ionic radius. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVeksbbM&md5=eacb0b2d2f2ad2e595f2de20093b3461
- 53 Patil, S. ; Sandberg, A. ; Heckert, E. ; Self, W. ; Seal, S. Protein Adsorption and Cellular Uptake of Cerium Oxide Nanoparticles as a Function of Zeta Potential . Biomaterials 2007 , 28 , 4600 – 4607 , DOI: 10.1016/j.biomaterials.2007.07.029 53 Protein adsorption and cellular uptake of cerium oxide nanoparticles as a function of zeta potential Patil, Swanand; Sandberg, Amanda; Heckert, Eric; Self, William; Seal, Sudipta Biomaterials ( 2007 ), 28 ( 31 ), 4600-4607 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) The surface chem. of biomaterials can have a significant impact on their performance in biol. applications. The recent work suggests that cerium oxide nanoparticles are potent antioxidants in cell culture models and the authors have evaluated several therapeutic applications of these nanoparticles in different biol. systems. Knowledge of protein adsorption and cellular uptake will be very useful in improving the beneficial effects of cerium oxide nanoparticles in biol. In the present study, the authors detd. the effect of zeta potential of cerium oxide nanoparticles on adsorption of bovine serum albumin (BSA) and cellular uptake in adenocarcinoma lung cells (A549). The zeta potential of the nanoparticles was varied by dispersing them in various acidic and basic pH solns. UV-visible spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS) were used for the protein adsorption and cellular uptake studies, resp. Nanoceria samples having pos. zeta potential were found to adsorb more BSA while the samples with neg. zeta potential showed little or no protein adsorption. The cellular uptake studies showed preferential uptake for the neg. charged nanoparticles. These results demonstrate that electrostatic interactions can play an important factor in protein adsorption and cellular uptake of nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXptFygurg%253D&md5=7b40e8f70d0d9f4c01624d21b7d321bd
- 54 Shah, M. ; Fawcett, D. ; Sharma, S. ; Tripathy, S. K. ; Poinern, G. E. J. Green Synthesis of Metallic Nanoparticles via Biological Entities . Materials 2015 , 8 , 7278 – 7308 , DOI: 10.3390/ma8115377 54 Green synthesis of metallic nanoparticles via biological entities Shah, Monaliben; Fawcett, Derek; Sharma, Shashi; Tripathy, Suraj Kumar; Poinern, Gerrard Eddy Jai Materials ( 2015 ), 8 ( 11 ), 7278-7308 CODEN: MATEG9 ; ISSN: 1996-1944 . ( MDPI AG ) Nanotechnol. is the creation, manipulation and use of materials at the nanometer size scale (1 to 100 nm). At this size scale there are significant differences in many material properties that are normally not seen in the same materials at larger scales. Although nanoscale materials can be produced using a variety of traditional phys. and chem. processes, it is now possible to biol. synthesize materials via environment-friendly green chem. based techniques. In recent years, the convergence between nanotechnol. and biol. has created the new field of nanobiotechnol. that incorporates the use of biol. entities such as actinomycetes algae, bacteria, fungi, viruses, yeasts, and plants in a no. of biochem. and biophys. processes. The biol. synthesis via nanobiotechnol. processes have a significant potential to boost nanoparticles prodn. without the use of harsh, toxic, and expensive chems. commonly used in conventional phys. and chem. processes. The aim of this review is to provide an overview of recent trends in synthesizing nanoparticles via biol. entities and their potential applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXls12isrc%253D&md5=ad52fe8043087d1e502a7a799bb35168
- 55 Xu, S. ; Zhang, J. ; Paquet, C. ; Lin, Y. ; Kumacheva, E. From Hybrid Microgels to Photonic Crystals . Adv. Funct. Mater. 2003 , 13 , 468 – 472 , DOI: 10.1002/adfm.200304338 55 From hybrid microgels to photonic crystals Xu, Shengqing; Zhang, Jiguang; Paquet, Chantal; Lin, Yuankun; Kumacheva, Eugenia Advanced Functional Materials ( 2003 ), 13 ( 6 ), 468-472 CODEN: AFMDC6 ; ISSN: 1616-301X . ( Wiley-VCH Verlag GmbH & Co. KGaA ) We have synthesized semiconductor and metal nanoparticles (NPs) in the constrained geometry of polymer microgels. We used electrostatically driven attraction between the ionic groups of the microgels and the precursor cations in the bulk liq. medium to introduce the cations in the interior of the microgel. In the second step, the cations in the microgel interior reacted with the anion (to obtain semiconductor NPs) or they were treated with a reducing agent (to obtain metal NPs). Good control over the size and the concn. of the NPs in the microgel particles was achieved by changing the compn. of the corresponding microgel. The doped microgel spheres were heated at pH 4 above the vol.-transition temp. of the polymer to expel the water from the microsphere interior; then the polymer was encapsulated with a hydrophobic polymeric shell. Hybrid core-shell particles were used as the building blocks of the nanostructured material with properties of a photonic crystal. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXltFeksrg%253D&md5=4935887e3a24f64f7d1508651f0e2adb
- 56 Epifani, M. ; Giannini, C. ; Tapfer, L. ; Vasanelli, L. Sol – Gel Synthesis and Characterization of Ag and Au Nanoparticles in SiO2, TiO2, and ZrO2 thin films . J. Am. Ceram. Soc. 2000 , 83 , 2385 – 2393 , DOI: 10.1111/j.1151-2916.2000.tb01566.x 56 Sol-gel synthesis and characterization of Ag and Au nanoparticles in SiO2, TiO2, and ZrO2 thin films Epifani, Mauro; Giannini, Cinzia; Tapfer, Leander; Vasanelli, Lorenzo Journal of the American Ceramic Society ( 2000 ), 83 ( 10 ), 2385-2393 CODEN: JACTAW ; ISSN: 0002-7820 . ( American Ceramic Society ) Silver and gold nanoparticles were synthesized by the sol-gel process in SiO2, TiO2, and ZrO2 thin films. A versatile method, based on the use of coordination chem., is presented for stabilizing Ag+ and Au3+ ions in sol-gel systems. Various ligands of the metal ions were tested, and for each system it was possible to find a suitable ligand capable of stabilizing the metal ions and preventing gold pptn. onto the film surface. Thin films were prepd. by spin-coating onto glass or fused silica substrates and then heat-treated at various temps. in air or H2 atmosphere for nucleating the metal nanoparticles. The Ag particle size was about 10 nm after heating the SiO2 film at 600°C and the TiO2 and ZrO2 films at 500°C. After heat treatment at 500°C, the Au particle size was 13 and 17 nm in the TiO2 and ZrO2 films, resp. The films were characterized by UV-vis optical absorption spectroscopy and X-ray diffraction, for studying the nucleation and the growth of the metal nanoparticles. The results are discussed with regard to the embedding matrix, the temp., and the atm. of the heat treatment, and it is concluded that crystn. of TiO2 and ZrO2 films may hinder the growth of Ag and Au particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXntlGrsLw%253D&md5=ec0dc5c3d8cd525b926e5f19e8304bb2
- 57 Gupta, N. ; Singh, H. P. ; Sharma, R. K. Single-Pot Synthesis: Plant Mediated Gold Nanoparticles Catalyzed Reduction of Methylene Blue in Presence of Stannous Chloride . Colloids Surf., A 2010 , 367 , 102 – 107 , DOI: 10.1016/j.colsurfa.2010.06.022 57 Single-pot synthesis: Plant mediated gold nanoparticles catalyzed reduction of methylene blue in presence of stannous chloride Gupta, Nikesh; Singh, Henam Premananda; Sharma, Rakesh Kumar Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2010 ), 367 ( 1-3 ), 102-107 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Gold nanoparticles of about 20 nm in diam. and having λ max at 542 nm is prepd. by addn. of HAuCl4 soln. to green tea leaves ext. at room temp. The synthetic route does not involve any toxic chems. or org. solvent and it is totally aq. phase synthesis; so it is a green approach. The synthesized nanoparticles were used as a catalyst for the redn. of methylene blue dye in the presence of Sn(II) in aq. and micellar media and the rate of redn. is detd. by measuring the decrease in absorbance of the dye at 663 nm spectrophotometrically. The rate of redn. follows the order RateSDS > RateCTAB > Ratewater. The activation energy as detd. using Arrhenius equation for the reaction catalyzed by gold nanoparticles is 38.42 kJ mol-1 and the slow reaction rate of uncatalyzed reaction has been manifested through larger activation energy of about 88.13 kJ mol-1. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtVantLfE&md5=02e32bb6600ec53143643a01aaa3f31a
- 58 Niemeyer, C. M. Nanoparticles, Proteins, and Nucleic Acids: Biotechnology Meets Materials Science . Angew. Chem., Int. Ed. 2001 , 40 , 4128 – 4158 , DOI: 10.1002/1521-3773(20011119)40:22<4128::AID-ANIE4128>3.0.CO;2-S 58 Nanoparticles, proteins, and nucleic acids: biotechnology meets materials science Niemeyer, Christof M. Angewandte Chemie, International Edition ( 2001 ), 40 ( 22 ), 4128-4158 CODEN: ACIEF5 ; ISSN: 1433-7851 . ( Wiley-VCH Verlag GmbH ) A review. Based on fundamental chem., biotechnol. and materials science have developed over the past three decades into today's powerful disciplines which allow the engineering of advanced tech. devices and the industrial prodn. of active substances for pharmaceutical and biomedical applications. This review is focused on current approaches emerging at the intersection of materials research, nanosciences, and mol. biotechnol. This novel and highly interdisciplinary field of chem. is closely assocd. with both the phys. and chem. properties of org. and inorg. nanoparticles, as well as to the various aspects of mol. cloning, recombinant DNA and protein technol., and immunol. Evolutionary optimized biomols. such as nucleic acids, proteins, and supramol. complexes of these components, are utilized in the prodn. of nanostructured and mesoscopic architectures from org. and inorg. materials. The highly developed instruments and techniques of today's materials research are used for basic and applied studies of fundamental biol. processes. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovFeisr0%253D&md5=e1198a7f5dce39d222fba59a6713c754
- 59 Shindel, M. M. ; Mohraz, A. ; Mumm, D. R. ; Wang, S. W. Modulating Colloidal Adsorption on a Two-Dimensional Protein Crystal . Langmuir 2009 , 25 , 1038 – 1046 , DOI: 10.1021/la802911p 59 Modulating Colloidal Adsorption on a Two-Dimensional Protein Crystal Shindel, Matthew M.; Mohraz, Ali; Mumm, Daniel R.; Wang, Szu-Wen Langmuir ( 2009 ), 25 ( 2 ), 1038-1046 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) The geometric and physicochem. properties of the protein streptavidin make it a useful building block in the construction and manipulation of nanoscale structures and devices. However, one requirement in exploiting streptavidin for "bottom-up" assembly is the capability to modulate protein-nanoparticle interactions. This work examines the effects of pH and the biotin-streptavidin interaction on the adsorption of colloidal gold onto a two-dimensional streptavidin crystal. Particle deposition was carried out below (pH 6), at (pH 7), and above (pH 8) the protein's isoelec. point with both biotinylated and nonbiotinylated nanoparticles. Particle surface coverage depends on deposition time and pH, and increases by 1.4-10 times when biotin is incorporated onto the particle surface. This coverage is highest for both particle types at pH 6 and decreases monotonically with increasing pH. Calcns. of interparticle potentials based on Derjaguin-Landau-Verwey-Overbeek (DLVO) theory demonstrate that this trend in surface coverage is most likely due to alterations in particle-surface electrostatic interactions and not a result of changes in interparticle electrostatic repulsion. Furthermore, post-adsorption alterations in pH demonstrate that electrostatically adsorbed particles can be selectively desorbed from the surface. Evaluation of the nonspecifically adsorbed fraction of biotinylated particles indicates that the receptor-ligand adsorption mechanism gives a higher rate of attachment to the substrate than nonspecific, electrostatic adsorption. This results in faster adsorption kinetics and higher coverages for biotinylated particles relative to the nonbiotinylated case. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsFals7vO&md5=0c4f7ad834fb0b94f88816ce5e85dcb2
- 60 Haruta, M. ; Yamada, N. ; Kobayashi, T. ; Iijima, S. Gold Catalysts Prepared by Coprecipitation for Low-Temperature Oxidation of Hydrogen and of Carbon Monoxide . J. Catal. 1989 , 115 , 301 – 309 , DOI: 10.1016/0021-9517(89)90034-1 60 Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S. Journal of Catalysis ( 1989 ), 115 ( 2 ), 301-9 CODEN: JCTLA5 ; ISSN: 0021-9517 . Novel Au catalysts were prepd. by copptn. from an aq. soln. of HAuCl4 and the nitrates of various transition metals. Calcination of the coppts. in air at 400° produced ultrafine Au particles <10 nm which were uniformly dispersed on the transition metal oxides. Among them, Au/α-Fe2O3, Au/Co3O4, and Au/NiO were highly active for H2 and CO oxidn., showing markedly enhanced catalytic activities due to the combined effect of Au and the transition metal oxides. For the oxidn. of CO they were active even at a temp. as low as -70°. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhtVamsbY%253D&md5=e5251756c7ba5548ab855a97d979cce4
- 61 Lisiecki, I. ; Pileni, M. P. Synthesis of Copper Metallic Clusters Using Reverse Micelles as Microreactors . J. Am. Chem. Soc. 1993 , 115 , 3887 – 3896 , DOI: 10.1021/ja00063a006 61 Synthesis of copper metallic clusters using reverse micelles as microreactors Lisiecki, I.; Pileni, M. P. Journal of the American Chemical Society ( 1993 ), 115 ( 10 ), 3887-96 CODEN: JACSAT ; ISSN: 0002-7863 . Reverse micelles were used to synthesize in situ nanometallic Cu particles. Metallic Cu particles are formed in mixed reverse micelles with N2H4 as the reducing agent. Small particles are obtained at low H2O content. The size of the metallic cluster increases 2-10 nm with increasing H2O content. The use of pure Cu surfactant mols. instead of mixed micelles favors the formation of cylindrical metallic particles. Large metallic Cu particles (20-28 nm) are formed by using NaBH4 as a reducing agent (in the absence of O and at low H2O content). The metallic clusters progressively disappear, forming instead Cu oxide particles with increasing H2O content. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVWksLo%253D&md5=8c8d4c3d9895995445147fa5dadd4c99
- 62 Jun, S. H. ; Cha, S. H. ; Kim, J. ; Cho, S. ; Park, Y. Crystalline Silver Nanoparticles by Using Polygala Tenuifolia Root Extract as a Green Reducing Agent . J. Nanosci. Nanotechnol. 2015 , 15 , 1567 – 1574 , DOI: 10.1166/jnn.2015.9031 62 Crystalline silver nanoparticles by using Polygala tenuifolia root extract as a green reducing agent Jun, Sang Hui; Cha, Song-Hyun; Kim, Jinwoong; Cho, Seonho; Park, Youmie Journal of Nanoscience and Nanotechnology ( 2015 ), 15 ( 2 ), 1567-1574 CODEN: JNNOAR ; ISSN: 1533-4880 . ( American Scientific Publishers ) Due to the emergence of multidrug-resistant bacteria, silver nanoparticles (AgNPs) have found interest as a new category of antibacterial agents. The toxicity of the chems. involved in the commonly employed chem. methods for synthesizing AgNPs present limitations for subsequent pharmaceutical and biomedical applications. In this report, 70% aq. ethanol exts. of Polygala tenuifolia root were used to reduce Ag+1 ions for AgNPs synthesis. The as-synthesized AgNPs were characterized via UV-Visible spectrophotometry, high resoln. transmission electron microscopy, at. force microscopy, X-ray diffraction, and Fourier transform IR spectroscopy. A strong surface plasmon resonance band was obsd. at 414 nm. Images from the high resoln. transmission electron microscopy and at. force microscopy demonstrated the spherical and irregular shapes of the AgNPs were synthesized. The AgNP cryst. structure was confirmed by the strong diffraction peaks in the X-ray diffraction results and by the bright circular spots obsd. in selected-area electron diffraction, whose av. diam. was measured to be 17.97 ± 8.63 nm or 15.12 nm via high resoln. transmission electron microscopy images or X-ray diffraction anal., resp. The as-synthesized AgNPs exerted the highest antibacterial activity against Escherichia coli among the tested Gram-pos. and Gram-neg. bacteria. The current method is eco-friendly, straight-forward, cost-effective, biocompatible, and easily scaled up to produce of AgNPs for applications in the treatment of bacterial infections. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXls1Cms7g%253D&md5=03bc61b74be2f0f6c00573ad799b5e91
- 63 Zhang, Q. W. ; Lin, L. G. ; Ye, W. C. Techniques for Extraction and Isolation of Natural Products: A Comprehensive Review . Chinese Medicine 2018 , DOI: 10.1186/s13020-018-0177-x There is no corresponding record for this reference.
- 64 El Maaiden, E. ; Bouzroud, S. ; Nasser, B. ; Moustaid, K. ; El Mouttaqi, A. ; Ibourki, M. ; Boukcim, H. ; Hirich, A. ; Kouisni, L. ; El Kharrassi, Y. A Comparative Study between Conventional and Advanced Extraction Techniques: Pharmaceutical and Cosmetic Properties of Plant Extracts . Molecules 2022 , 27 , 2074 , DOI: 10.3390/molecules27072074 64 A Comparative Study between Conventional and Advanced Extraction Techniques: Pharmaceutical and Cosmetic Properties of Plant Extracts El Maaiden, Ezzouhra; Bouzroud, Sarah; Nasser, Boubker; Moustaid, Khadija; El Mouttaqi, Ayoub; Ibourki, Mohamed; Boukcim, Hassan; Hirich, Abdelaziz; Kouisni, Lamfeddal; El Kharrassi, Youssef Molecules ( 2022 ), 27 ( 7 ), 2074 CODEN: MOLEFW ; ISSN: 1420-3049 . ( MDPI AG ) This study aimed to compare the influence of extn. methods on the pharmaceutical and cosmetic properties of medicinal and arom. plants (MAPs). For this purpose, the dried plant materials were extd. using advanced (microwave (MAE), ultrasonic (UAE), and homogenizer (HAE) assisted extns.) and conventional techniques (maceration, percolation, decoction, infusion, and Soxhlet). The tyrosinase, elastase, α-amylase, butyryl, and acetylcholinesterase inhibition were tested by using L-3,4 dihydroxy-phenylalanine, N-Succinyl-Ala-Ala-p-nitroanilide, butyryl, and acetylcholine as resp. substrates. Antioxidant activities were studied by ABTS, DPPH, and FRAP. In terms of extn. yield, advanced extn. techniques showed the highest values (MAE > UAE > HAE). Chem. profiles were dependent on the phenolic compds. tested, whereas the antioxidant activities were always higher, mainly in infusion and decoction as a conventional technique. In relation to the pharmaceutical and cosmetic properties, the highest inhibitory activities against α-amylase and acetylcholinesterase were obsd. for Soxhlet and macerated exts., whereas the highest activity against tyrosinase was obtained with MAE > maceration > Soxhlet. Elastase and butyrylcholinesterase inhibitory activities were in the order of Soxhlet > maceration > percolation, with no activities recorded for the other tested methods. In conclusion, advanced methods afford an ext. with high yield, while conventional methods might be an adequate approach for minimal changes in the biol. properties of the ext. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XhtVejs77E&md5=243d2c52e13b4d8ba315a9beb12800c3
- 65 Saifullah, M. ; McCullum, R. ; McCluskey, A. ; Vuong, Q. Comparison of Conventional Extraction Technique with Ultrasound Assisted Extraction on Recovery of Phenolic Compounds from Lemon Scented Tea Tree (Leptospermum Petersonii) Leaves . Heliyon 2020 , 6 , e03666 DOI: 10.1016/j.heliyon.2020.e03666 There is no corresponding record for this reference.
- 66 Fotsing Yannick Stéphane, F. ; Kezetas Jean Jules, B. ; El-Saber Batiha, G. ; Ali, I. ; Ndjakou Bruno, L. Extraction of Bioactive Compounds from Medicinal Plants and Herbs ; Natural Medicinal Plants , 2022 . There is no corresponding record for this reference.
- 67 Mahmoodi Esfanddarani, H. ; Abbasi Kajani, A. ; Bordbar, A. Green Synthesis of Silver Nanoparticles Using Flower Extract of Malva Sylvestris and Investigation of Their Antibacterial Activity . IET Nanobiotechnol 2018 , 12 , 412 – 416 , DOI: 10.1049/iet-nbt.2017.0166 67 Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity Mahmoodi Esfanddarani Hassan; Abbasi Kajani Abolghasem; Bordbar Abdol-Khalegh IET nanobiotechnology ( 2018 ), 12 ( 4 ), 412-416 ISSN: 1751-8741 . High-quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic-force microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20-40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MfjvFCgtQ%253D%253D&md5=300fce194b9b6e7c092fa87366095c49
- 68 Akhtar, M. S. ; Panwar, J. ; Yun, Y. S. Biogenic Synthesis of Metallic Nanoparticles by Plant Extracts . ACS Sustainable. Chem. Eng. 2013 , 1 , 591 – 602 , DOI: 10.1021/sc300118u 68 Biogenic Synthesis of Metallic Nanoparticles by Plant Extracts Akhtar, Mohd Sayeed; Panwar, Jitendra; Yun, Yeoung-Sang ACS Sustainable Chemistry & Engineering ( 2013 ), 1 ( 6 ), 591-602 CODEN: ASCECG ; ISSN: 2168-0485 . ( American Chemical Society ) A review. In recent years, nanobiotechnol. has emerged as an elementary division of modern science and a novel epoch in the fields of material science and is receiving global attention due to its ample applications. Various phys., chem., and biol. methods have been employed to synthesize nanomaterials. Biol. systems such as bacteria, fungi, actinomycetes, yeasts, viruses, and plants have been reported to synthesize various metal and metal oxide nanoparticles. Among these, biosynthesis of nanoparticles from plants seems to be a very effective method in developing a rapid, clean, nontoxic, and eco-friendly technol. The use of plant biomass or exts. for the biosynthesis of novel metal nanoparticles (silver, gold, platinum, and palladium) would be more significant if the nanoparticles were synthesized extracellularly and in a controlled manner according to their dispersity of shape and size. Owing to the rich biodiversity of plants, their potential use toward the synthesis of these noble metal nanoparticles is yet to be explored. The aim of this review is to provide the recent trends involved in the phytosynthesis of nobel metal nanoparticles in the past decade. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXltVCksr0%253D&md5=1bd67ecddd252fff33d1735637a20a05
- 69 Saravanakumar, K. ; Chelliah, R. ; Shanmugam, S. ; Varukattu, N. B. ; Oh, D. H. ; Kathiresan, K. ; Wang, M. H. Green Synthesis and Characterization of Biologically Active Nanosilver from Seed Extract of Gardenia Jasminoides Ellis . Journal of Photochemistry and Photobiology B: Biology 2018 , 185 , 126 – 135 , DOI: 10.1016/j.jphotobiol.2018.05.032 69 Green synthesis and characterization of biologically active nanosilver from seed extract of Gardenia jasminoides Ellis Saravanakumar, Kandasamy; Chelliah, Ramachandran; Shanmugam, Sabarathinam; Varukattu, Nipun Babu; Oh, Deog-Hwan; Kathiresan, Kandasamy; Wang, Myeong-Hyeon Journal of Photochemistry and Photobiology, B: Biology ( 2018 ), 185 ( ), 126-135 CODEN: JPPBEG ; ISSN: 1011-1344 . ( Elsevier B.V. ) This article reports the utilization of seed ext. (GSE) from Gardenia jasminoides Ellis. in the synthesis of silver nanoparticles (Gs-AgNPs) with versatile biol. activities. The synthesized Gs-AgNPs were spherical in shape, crystal lattice with an av. size of 20nm as confirmed by UV-vis spectrum, X-ray diffractometer (XRD), Transmission electron microscopy with Energy dispersive X-ray spectroscopy (TEM-EDS) and particle size analyses (PSA). Phenolic compds., proteins, and terpenoids were likely involved in the Gs-AgNPs synthesis, as indicated by Fourier-transform IR spectroscopy (FTIR) anal. The MBC of the Gs-AgNPs induced >70% bacterial cell death within 60min, as confirmed by growth curve anal. followed by Confocal laser scanning microscope (CLSM). Gs-AgNPs showed the highest scavenging activity for 1, 2-diphenyl-1-picrylhydrazyl DPPH radical (92.3±0.86%), Nitric oxide (NO) radical (72.5±2.15%), and Hydrogen peroxide H2O2 radical (85.25±1.45%). The Gs-AgNPs generated high reactive oxygen species (ROS) resulting in induced apoptosis as evident by up-regulation of apoptosis-related protein. In addn., the photocatalytic results revealed about 92% of the redn. in Coomassie Brilliant Blue dye color with Gs-AgNPs. Hence, this work provided economically viable and ecol. sustainable Gs-AgNPs as an alternative biomaterial for future therapeutic applications as antimicrobial, antioxidant, anti-cancer agents and in dye degrdn. for water remediation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtFSgt7nL&md5=941c5fb8bad3a6e720f4595445e0b207
- 70 Behravan, M. ; Hossein Panahi, A. ; Naghizadeh, A. ; Ziaee, M. ; Mahdavi, R. ; Mirzapour, A. Facile Green Synthesis of Silver Nanoparticles Using Berberis Vulgaris Leaf and Root Aqueous Extract and Its Antibacterial Activity . Int. J. Biol. Macromol. 2019 , 124 , 148 – 154 , DOI: 10.1016/j.ijbiomac.2018.11.101 70 Facile green synthesis of silver nanoparticles using Berberis vulgaris leaf and root aqueous extract and its antibacterial activity Behravan, Mahmoodreza; Hossein Panahi, Ayat; Naghizadeh, Ali; Ziaee, Masood; Mahdavi, Roya; Mirzapour, Aliyar International Journal of Biological Macromolecules ( 2019 ), 124 ( ), 148-154 CODEN: IJBMDR ; ISSN: 0141-8130 . ( Elsevier B.V. ) Most recently, silver nanoparticles due to antibacterial properties have been considered in medical science. So the aim of the study was green synthesis of silver nanoparticles using Berberis vulgaris leaf and root aq. ext. and its antibacterial activity. After collection, identification and extn. of Berberis vulgaris was performed prodn. of silver nanoparticles. In the study effect of parameters such as AgNO3 concn. (0.5, 1, 3, 10 mM), aq. ext. (3, 5, 10, 15, 30 mL) and contact time (1, 2, 6, 12, 24 h) were investigated in the synthesis of nanoparticles and also the antibacterial effect of these nanoparticles was studied on Escherichia coli and Staphylococcus aureus bacteria by Disk diffusion test and Min. Inhibitory Concn. test (MIC). According to XRD results and anal. of TEM, nanoparticles have spherical shapes and size of 30 to 70 nm. On the other hand antibacterial tests showed these nanoparticles have more antibacterial activity more than other exts. Result showed the biosynthesis of silver nanoparticles using aq. ext. of Berberis vulgaris is a clean, inexpensive and safe method that has not been used any toxic substance and consequently does not side effects and this nanoparticles has a high antibacterial activity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXitlenu7%252FN&md5=aaa414ca2a6cbc26f6885014c0226f29
- 71 Fardsadegh, B. ; Jafarizadeh-Malmiri, H. Aloe Vera Leaf Extract Mediated Green Synthesis of Selenium Nanoparticles and Assessment of Their in Vitro Antimicrobial Activity against Spoilage Fungi and Pathogenic Bacteria Strains . Green. Process. Synth. 2019 , 8 , 399 – 407 , DOI: 10.1515/gps-2019-0007 71 Aloe vera leaf extract mediated green synthesis of selenium nanoparticles and assessment of their In vitro antimicrobial activity against spoilage fungi and pathogenic bacteria strains Fardsadegh, Borna; Jafarizadeh-Malmiri, Hoda Green Processing and Synthesis ( 2019 ), 8 ( 1 ), 399-407 CODEN: GPSREC ; ISSN: 2191-9550 . ( Walter de Gruyter GmbH ) Selenium as an essential trace element for the health of the humans was used to hydrothermally synthesis of selenium nanoparticle (Se NPs) using Aloe vera leaf ext. (ALE). Effects of synthesis parameters namely; amt. of ALE (1-5 mL) and amt. of Na2SeO3 soln. (10-30 mL), on the particle size and color intensity of the soln. contg. Se NPs were studied using response surface methodol. FT-IR spectroscopy, UV-Vis spectrophotometry, DLS analyzer and TEM were used to det. the specifications of the ALE and synthesized Se NPs. Obtained results indicated that the ALE contained several bioactive compds., which they had hydroxyl and amide I groups in their structures and these two functional groups had key roles in the redn. of the selenium ions to form Se NPs and stabilizing of them. Furthermore, spherical fabricated Se NPs using obtained optimum synthesis parameters, 4.92 mL of ALE and 13.03 mL of Na2SeO3 soln., had color intensity, mean particle size, zeta potential and polydispersity index values of 3.0% a.u., 50 nm, -18 mV and 0.344, resp. according to the DLS anal. The synthesized Se NPs had also high antibacterial and antifungal activities against 4 selected pathogenic bacteria and spoilage fungi strains. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitlansbjL&md5=c151c16ba3be0c2264308a1d316be85e
- 72 Bergeson, L. L. Sustainable Nanomaterials: Emerging Governance Systems . ACS Sustainable. Chem. Eng. 2013 , 1 , 724 – 730 , DOI: 10.1021/sc4000863 72 Sustainable Nanomaterials: Emerging Governance Systems Bergeson, Lynn L. ACS Sustainable Chemistry & Engineering ( 2013 ), 1 ( 7 ), 724-730 CODEN: ASCECG ; ISSN: 2168-0485 . ( American Chemical Society ) A review concerning domestic and international laws, regulations, policies, and government and private-party governance programs and oversight systems to assess regulatory initiatives addressing potential enhancement of nanomaterial risks and their utility to nurture commercialization of nanoscale materials, is given. Whether existing laws are adequate to address potential risks from nanoscale materials and promote their sustainable use will inspire debate and governance initiatives for years to come. Topics discussed include: background; green nanotechnol.; emerging governance frameworks (adequacy of existing legal authorities, federal regulatory initiatives, state and local regulatory initiatives, key std.-setting initiatives, key private-sector stewardship initiatives [describe material and application; profile life cycle(s); evaluate risks; assess risk management;, decide, document, and act; review and adapt]); fostering and promoting green nanotechnol. (develop a life cycle assessment appropriate for green nanoproducts, establish performance and branding stds. for green nanotechnol., provide tax and related business incentives to innovators to encourage application of green nanotechnol., increase patent term protection for green nanoproducts, establish a Design for Environment green nano category, provide greater funding for green nano research, convene a forum to develop and implement green nano principles in a systematic way, actively promote green nano in regulatory and voluntary initiatives); and conclusions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXpsFWqsL8%253D&md5=fd2c1e765ac035e1ea932392c30e0145
- 73 Hutchison, J. E. Greener Nanoscience: A Proactive Approach to Advancing Applications and Reducing Implications of Nanotechnology . ACS Nano 2008 , 2 , 395 – 402 , DOI: 10.1021/nn800131j 73 Greener Nanoscience: A Proactive Approach to Advancing Applications and Reducing Implications of Nanotechnology Hutchison, James E. ACS Nano ( 2008 ), 2 ( 3 ), 395-402 CODEN: ANCAC3 ; ISSN: 1936-0851 . ( American Chemical Society ) Nanotechnol. continues to offer new materials and applications that will benefit society, yet there is growing concern about the potential health and environmental impacts of prodn. and use of nanoscale products. Although hundreds of studies of nanomaterial hazards were reported, due (largely) to the complexity of the nanomaterials, there is no consensus about the impact these hazards will have. This focus describes the need for a research agenda that addresses these nanomaterial complexities through coordinated research on the applications and implications of new materials, wherein nanomaterials scientists play a central role in the move from understanding to minimizing nanomaterial hazards. Greener nanoscience is presented as an approach to detg. and implementing the design rules for safer nanomaterials and safer, more efficient processes. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjsF2ktLo%253D&md5=df5c52801fb2a75d813aad46c6d230d8
- 74 Dahl, J. A. ; Maddux, B. L. S. ; Hutchison, J. E. Toward Greener Nanosynthesis . Chem. Rev. 2007 , 107 , 2228 – 2269 , DOI: 10.1021/cr050943k 74 Toward Greener Nanosynthesis Dahl, Jennifer A.; Maddux, Bettye L. S.; Hutchison, James E. Chemical Reviews (Washington, DC, United States) ( 2007 ), 107 ( 6 ), 2228-2269 CODEN: CHREAY ; ISSN: 0009-2665 . ( American Chemical Society ) A review of application of green chem. principles in nanosynthesis. Green nanoscience, application of the principles of green chem. to nanoscience,toward greener synthetic methods for functionalized metal nanoparticles (citrate reactions, direct synthesis of ligand-stabilized nanoparticles, seeded growth and shape control of nanoparticles, and emerging approaches in nanoparticle synthesis), toward greener prepns. of semiconductor and inorg. oxide nanoparticles (cadmium selenide and cadmium sulfide, zinc nanoparticles, and iron oxides), alternate solvents and energy source for nanoparticle synthesis (supercrit. fluids, ionic liqs., sonochem., laser ablation, and microwave), bio-based approaches (shape control with biomols., and whole organism approaches), functionalization (postsynthetic modification of the ligand shell, and ligand exchange), and nanoparticle assembly (assembly of extended nanoparticle-based array in soln. and directed assembly on surfaces and scaffolds) are considered. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXmtlaks7s%253D&md5=7f9114f08863ae6d684bff60d78a65e7
- 75 Korbekandi, H. ; Iravani, S. ; Abbasi, S. Production of Nanoparticles Using Organisms . Crit. Rev. Biotechnol. 2009 , 29 , 279 – 306 , DOI: 10.3109/07388550903062462 75 Production of nanoparticles using organisms Korbekandi, Hassan; Iravani, Siavash; Abbasi, Sajjad Critical Reviews in Biotechnology ( 2009 ), 29 ( 4 ), 279-306 CODEN: CRBTE5 ; ISSN: 0738-8551 . ( Informa Healthcare ) A review. Recent developments in the biosynthesis of nanomaterials have demonstrated the important role of biol. systems and microorganisms in nanoscience and nanotechnol. These organisms show a unique potential in environmentally friendly prodn. and accumulation of nanoparticles with different shapes and sizes. Therefore, researchers in the field of nanoparticle synthesis are focusing their attention to biol. systems. In order to obtain different applied chem. compns., controlled monodispersity, desired morphologies (e.g., amorphous, spherical, needles, cryst., triangular, and hexagonal), and interested particle size, they have investigated the biol. mechanism and enzymic process of nanoparticle prodn. In this review, most of these organisms used in nanoparticle synthesis are shown. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVyjtLfP&md5=6c24aa5f16cde3070d4d82f99bdef4a8
- 76 Virkutyte, J. ; Varma, R. S. Green Synthesis of Nanomaterials: Environmental Aspects . ACS Symp. Ser. 2013 , 11–39 . There is no corresponding record for this reference.
- 77 Sujoy, K. ; Marsili, E. Bioinspired Metal Nanoparticle: Synthesis, Properties and Application . Nanomaterials 2011 , DOI: 10.5772/25305 There is no corresponding record for this reference.
- 78 Fabrega, J. ; Luoma, S. N. ; Tyler, C. R. ; Galloway, T. S. ; Lead, J. R. Silver Nanoparticles: Behaviour and Effects in the Aquatic Environment . Environ. Int. 2011 , 37 , 517 – 531 , DOI: 10.1016/j.envint.2010.10.012 78 Silver nanoparticles: Behaviour and effects in the aquatic environment Fabrega, Julia; Luoma, Samuel N.; Tyler, Charles R.; Galloway, Tamara S.; Lead, Jamie R. Environment International ( 2011 ), 37 ( 2 ), 517-531 CODEN: ENVIDV ; ISSN: 0160-4120 . ( Elsevier Ltd. ) This review summaries and evaluates the present knowledge on the behavior, the biol. effects and the routes of uptake of silver nanoparticles (Ag NPs) to organisms, with considerations on the nanoparticle physicochem. in the ecotoxicity testing systems used. Different types of Ag NP syntheses, characterization techniques and predicted current and future concns. in the environment are also outlined. Rapid progress in this area has been made over the last few years, but there is still a crit. lack of understanding of the need for characterization and synthesis in environmental and ecotoxicol. studies. Concn. and form of nanomaterials in the environment are difficult to quantify and methodol. progress is needed, although sophisticated exposure models show that predicted environmental concns. (PECs) for Ag NPs in different environmental compartments are at the range of ng L-1 to mg kg-1. The ecotoxicol. literature shows that concns. of Ag NPs below the current and future PECs, as low as just a few ng L-1, can affect prokaryotes, invertebrates and fish indicating a significant potential, though poorly characterized, risk to the environment. Mechanisms of toxicity are still poorly understood although it seems clear that in some cases nanoscale specific properties may cause biouptake and toxicity over and above that caused by the dissolved Ag ion. This review concludes with a set of recommendations for the advancement of understanding of the role of nanoscale silver in environmental and ecotoxicol. research. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFCjtr8%253D&md5=01ba858a5e7e8496b7a875d075af5ae8
- 79 Hassellöv, M. ; Readman, J. W. ; Ranville, J. F. ; Tiede, K. Nanoparticle Analysis and Characterization Methodologies in Environmental Risk Assessment of Engineered Nanoparticles . Ecotoxicology 2008 , 17 , 344 – 361 , DOI: 10.1007/s10646-008-0225-x 79 Nanoparticle analysis and characterization methodologies in environmental risk assessment of engineered nanoparticles Hassellov Martin; Readman James W; Ranville James F; Tiede Karen Ecotoxicology (London, England) ( 2008 ), 17 ( 5 ), 344-61 ISSN: 0963-9292 . Environmental risk assessments of engineered nanoparticles require thorough characterization of nanoparticles and their aggregates. Furthermore, quantitative analytical methods are required to determine environmental concentrations and enable both effect and exposure assessments. Many methods still need optimization and development, especially for new types of nanoparticles in water, but extensive experience can be gained from the fields of environmental chemistry of natural nanomaterials and from fundamental colloid chemistry. This review briefly describes most methods that are being exploited in nanoecotoxicology for analysis and characterization of nanomaterials. Methodological aspects are discussed in relation to the fields of nanometrology, particle size analysis and analytical chemistry. Differences in both the type of size measures (length, radius, aspect ratio, etc.), and the type of average or distributions afforded by the specific measures are compared. The strengths of single particle methods, such as electron microscopy and atomic force microscopy, with respect to imaging, shape determinations and application to particle process studies are discussed, together with their limitations in terms of counting statistics and sample preparation. Methods based on the measurement of particle populations are discussed in terms of their quantitative analyses, but the necessity of knowing their limitations in size range and concentration range is also considered. The advantage of combining complementary methods is highlighted. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czktFOitA%253D%253D&md5=9cc89abcea0d3c24b5f762b70ef75d83
- 80 Stuart, B. H. Biological Applications of Infrared Spectroscopy ; John Wiley & Sons , 1997 . There is no corresponding record for this reference.
- 81 Lee, D. C. ; Chapman, D. Infrared Spectroscopic Studies of Biomembranes and Model Membranes . Biosci. Rep. 1986 , 6 , 235 – 256 , DOI: 10.1007/BF01115153 81 Infrared spectroscopic studies of biomembranes and model membranes Lee, David C.; Chapman, Dennis Bioscience Reports ( 1986 ), 6 ( 3 ), 235-56 CODEN: BRPTDT ; ISSN: 0144-8463 . A review with many refs. The application of IR spectroscopy to the study of membrane lipids, membrane proteins, and lipid-protein interactions is discussed. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28Xktlynsrs%253D&md5=e90a984efbc1bfa73ba717e4082e8bc1
- 82 Schmitt, J. ; Flemming, H. C. FTIR-Spectroscopy in Microbial and Material Analysis . Int. Biodeterior. Biodegrad. 1998 , 41 , 1 – 11 , DOI: 10.1016/S0964-8305(98)80002-4 82 FTIR-spectroscopy in microbial and material analysis Schmitt, Jurgen; Flemming, Hans-Curt International Biodeterioration & Biodegradation ( 1998 ), 41 ( 1 ), 1-11 CODEN: IBBIES ; ISSN: 0964-8305 . ( Elsevier Science Ltd. ) The investigation of the development and the properties of biofilms is difficult because classical microbiol. does not offer non-destructive methods other than microscopical observations. This paper discusses the use of different Fourier transform IR spectroscopy (FTIR-spectroscopy) techniques as a means to investigate microorganisms in biofilms. FTIR-spectroscopy is suitable for the identification of microorganisms and presents a new addn. to taxonomic and genetic methods. The FTIR anal. of bacterial isolates provides fingerprint spectra, allowing the rapid characterization of microbial strains. Secondly, the FTIR-attenuated total reflection (ATR) technique can be used for the observation of biofilms forming directly on the interface of an ATR crystals such as germanium. These crystals can be coated to obtain a surface more relevant to study interfacial processes. Spectra can be acquired non-destructively, in situ and in real time. This method is suitable for fundamental biofilm research, as well as for monitoring of biofilm formation, e.g., in an ultrapure or drinking water systems. Furthermore, FTIR-ATR also allows the rapid anal. of deposits on surfaces, e.g., filtration membranes. The anal. discrimination between microorganisms, inorg. material or other foulants can be obtained. Thirdly, with the diffuse reflectance technique (DRIFT) it is possible to investigate reflecting surfaces like metals or very small samples. The compn. of surface coatings like biomass or other surface contaminants can be detected. These different measurement techniques demonstrate that FTIR -spectroscopy is suitable for biofilm and surface anal. and can be applied in many different ways. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXktFOkt74%253D&md5=5fa35e7f310a6ea30c914c4994aea6f0
- 83 Mathieu, J. P. Optics ; Pergamon Press : Oxford, NY , 1975 . There is no corresponding record for this reference.
- 84 Rani, P. ; Kumar, V. ; Singh, P. P. ; Matharu, A. S. ; Zhang, W. ; Kim, K. H. ; Singh, J. ; Rawat, M. Highly Stable AgNPs Prepared via a Novel Green Approach for Catalytic and Photocatalytic Removal of Biological and Non-Biological Pollutants . Environ. Int. 2020 , 143 , 105924 , DOI: 10.1016/j.envint.2020.105924 84 Highly stable AgNPs prepared via a novel green approach for catalytic and photocatalytic removal of biological and non-biological pollutants Rani, Pooja; Kumar, Vanish; Singh, Prit Pal; Matharu, Avtar Singh; Zhang, Wei; Kim, Ki-Hyun; Singh, Jagpreet; Rawat, Mohit Environment International ( 2020 ), 143 ( ), 105924 CODEN: ENVIDV ; ISSN: 0160-4120 . ( Elsevier Ltd. ) Increases in biol. and non-biol. pollutants pose a significant threat to environmental systems. In an effort to develop an effective means to treat such pollutants, the use of Phaseolus vulgaris (kidney beans) as reducing and capping agents is proposed for the green synthesis of highly stable silver nanoparticles (AgNPs) with a face-centered cubic (fcc) cryst. structure (size range: 10-20 nm). The potent role of the resulting AgNPs was found as triple platforms (photocatalyst, catalyst, and antimicrobial disinfectant). AgNPs were able to photocatalytically degrade approx. 97% of reactive red-141 (RR-141) dye within 150 min of exposure (quantum efficiency of 3.68 x 10-6 mol.photon-1 and a removal reaction kinetic rate of 1.13 x 10-2 mmol g-1 h-1). The role of specific reactive oxygen species (ROS) in the photocatalytic process and complete mineralization of dye was also explored through scavenger and COD (COD) expts., resp. As an catalyst, AgNPs were also capable of reducing 4-nitrophenol to 4-aminophenol within 15 min. Overall, AgNPs showed excellent stability as catalyst and photocatalyst even after five test cycles. As an antimicrobial agent, the AgNPs are effective against both gram-pos. (Bacillus subtilis) and -neg. bacteria (Escherichia coli), with the zones of clearance as 15 and 18 mm, resp. Thus, the results of this study validate the triple role of AgNPs derived via green synthesis as a photocatalyst, catalyst, and antimicrobial agent for effective environmental remediation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2isbjJ&md5=663bc1cac04b4282fb262b311aad405d
- 85 Uddin, A. K. M. R. ; Siddique, M. A. B. ; Rahman, F. ; Ullah, A. K. M. A. ; Khan, R. Cocos Nucifera Leaf Extract Mediated Green Synthesis of Silver Nanoparticles for Enhanced Antibacterial Activity . J. Inorg. Organomet. Polym. Mater. 2020 , 30 , 3305 – 3316 , DOI: 10.1007/s10904-020-01506-9 85 Cocos nucifera Leaf Extract Mediated Green Synthesis of Silver Nanoparticles for Enhanced Antibacterial Activity Uddin, A. K. M. Royhan; Siddique, Md. Abu Bakar; Rahman, Farjana; Ullah, A. K. M. Atique; Khan, Rahat Journal of Inorganic and Organometallic Polymers and Materials ( 2020 ), 30 ( 9 ), 3305-3316 CODEN: JIOPAY ; ISSN: 1574-1443 . ( Springer ) In this work, we have successfully green synthesized the AgNPs using Cocos nucifera leaf aq. ext. as the natural reducing and stabilizing agent, and aq. silver nitrate (AgNO3) soln. as a precursor by a newly developed technique. The synthesized AgNPs were identified by XRD anal. as a cubic crystal system with an av. crystallite size of 14.2 nm. The aq. colloidal suspension of AgNPs shows a UV-Vis absorption maxima of 380 nm indicating its formation. FT-IR anal. identified the C-N, -OH and N-H as the major and probable functional groups in the leaf ext. responsible for the prodn. of stable AgNPs. The results of antibacterial studies of the material showed the considerable zones of inhibition against both Gram-pos. (Staphylococcus aureus and Bacillus subtilis) and Gram-neg. (Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Citrobacter freundii) bacteria ranging from 10 to 20 mm with less inhibition for the former than the latter. The max. (20 mm) and min. (10 mm) inhibition zone was shown by C. freundii and Bacillus subtilis, resp. and P. aeruginosa shows the second-highest zone of inhibition (19 mm). The antibacterial performance of the material implies that the C. nucifera leaf ext. mediated green synthesized AgNPs can be regarded as a potential candidate for antimicrobial application appreciably. Graphic Abstr.: [graphic not available: see fulltext]. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlt1WjtL0%253D&md5=1a81ec1aa941f16fa2073577f7280bac
- 86 AlMasoud, N. ; Alomar, T. S. ; Awad, M. A. ; El-Tohamy, M. F. ; Soliman, D. A. Multifunctional green silver nanoparticles in pharmaceutical and biomedical applications . Green Chem. Lett. Rev. 2020 , 13 , 316 – 327 , DOI: 10.1080/17518253.2020.1839572 86 Multifunctional green silver nanoparticles in pharmaceutical and biomedical applications Almasoud, Najla; Alomar, Taghrid S.; Awad, Manal A.; El-Tohamy, Maha F.; Soliman, Dina A. Green Chemistry Letters and Reviews ( 2020 ), 13 ( 4 ), 316-327 CODEN: GCLRAI ; ISSN: 1751-7192 . ( Taylor & Francis Ltd. ) The present study concerned with the use of an aq. ginger ext. as naturally and ecofriendly reducing and stabilizing agent in the synthesis of silver nanoparticles (AgNPs). The unique physicochem. characteristics of green synthesized AgNPs exhibit high potential antimicrobial activity and displayed an impact role in pharmaceutical detns. To confirm the nanoscale of green synthesized AgNPs, various microscopic and spectroscopic techniques were performed. The synthesized nanoparticles were screened for their antimicrobial activity against several strains of bacteria and fungi. The obtained results showed excellent bactericidal and fungicidal effects. Also, the spectrofluorimetric anal. of anastrozole drug in bulk powder and dosage form was investigated. The suggested method displayed linear relationship between the drug concns. and the fluorescence intensity between 2 and 100μgmL-1 with regression equation was IFL = 9.1917C+ 65.945, n = 10 and r = 0.9995 at λex 390 and λem 440 nm. The green synthesized AgNPs using ginger ext. demonstrated a potential activity in pharmaceutical and biomedical fields. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXjsFKqtw%253D%253D&md5=fe81995e83d8a86342eeb7a46e1d9cfb
- 87 Awad, M. A. ; Hendi, A. ; Ortashi, K. M. ; Alzahrani, B. ; Soliman, D. ; Alanazi, A. ; Alenazi, W. ; Taha, R. M. ; Ramadan, R. ; El-Tohamy, M. ; AlMasoud, N. ; Alomar, T. S. Biogenic Synthesis of Silver Nanoparticles Using Trigonella Foenum-Graecum Seed Extract: Characterization, Photocatalytic and Antibacterial Activities . Sensors and Actuators A: Physical 2021 , 323 , 112670 , DOI: 10.1016/j.sna.2021.112670 87 Biogenic synthesis of silver nanoparticles using Trigonella foenum-graecum seed extract: Characterization, photocatalytic and antibacterial activities Awad, Manal A.; A. Hendi, Awatif; Ortashi, Khalid Mustafa; Alzahrani, Batool; Soliman, Dina; Alanazi, Amnah; Alenazi, Wadha; Taha, Rasha Mohammed; Ramadan, Rasha; El-Tohamy, Maha; AlMasoud, Najla; Alomar, Taghrid S. Sensors and Actuators, A: Physical ( 2021 ), 323 ( ), 112670 CODEN: SAAPEB ; ISSN: 0924-4247 . ( Elsevier B.V. ) A biogenic approach in the synthesis of nanoparticles has been the current trend in nanoscience attributed to the fact that it is an environmentally benign process which is safe to be used in biomedical applications. The present study describes a green mode of synthesis of silver nanoparticles using Trigonella foenum-graecum(fenugreek) with minimal scale size and ultra-stable features. The synthesized nanoparticles were characterized using UV-vis spectroscopy which showed a max. absorption peak at 443 nm. The electronmicrographs of transmission and scanning electron microscopes predominantly spherical and not aggregated nanoparticles with an irregular array of an av. diam. of 82.53 nm. The photocatalytic activity of silver nanoparticles was assessed by depredating Rhodamine B dye under light irradn. The photodegrdn. of Rhodamine B dye was time-dependent followed by a complete photodegrdn. (nearly 93%) with decoloration after 216 h. Further, the antibacterial activity of the silver nanoparticles was evaluated using three different bacterial strains and the zones of inhibition were shown to be (14, 2.0 mm), (5.0, 2.0 mm) and (10, 0.9 mm) for E. coli, S. aureus and Bacillus cereus, resp. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXmtFKnur0%253D&md5=ebfa00977fa3435abc36187d38d49582
- 88 Devaraj, P. ; Kumari, P. ; Aarti, C. ; Renganathan, A. Synthesis and Characterization of Silver Nanoparticles Using Cannonball Leaves and Their Cytotoxic Activity against MCF-7 Cell Line . J. Nanotechnol. 2013 , 2013 , 1 – 5 , DOI: 10.1155/2013/598328 There is no corresponding record for this reference.
- 89 Capaldi Arruda, S. C. ; Diniz Silva, A. L. ; Moretto Galazzi, R. ; Antunes Azevedo, R. ; Zezzi Arruda, M. A. Nanoparticles Applied to Plant Science: A Review . Talanta 2015 , 131 , 693 – 705 , DOI: 10.1016/j.talanta.2014.08.050 89 Nanoparticles applied to plant science: A review Capaldi Arruda, Sandra Cristina; Diniz Silva, Alisson Luiz; Moretto Galazzi, Rodrigo; Antunes Azevedo, Ricardo; Zezzi Arruda, Marco Aurelio Talanta ( 2015 ), 131 ( ), 693-705 CODEN: TLNTA2 ; ISSN: 0039-9140 . ( Elsevier B.V. ) A review. The present review addresses certain important aspects regarding nanoparticles and the environment, with an emphasis on plant science. The prodn. and characterization of nanoparticles is the focus of this review, providing an idea of the range and the consolidation of these aspects in the literature, with modifications on the routes of synthesis and the application of the anal. techniques for characterization of the nanoparticles (NPs). Addnl., aspects related to the interaction between the NPs and plants, their toxicities, and the phytoremediation process, among others, are also discussed. Future trends are also presented, supplying evidence for certain possibilities regarding new research involving nanoparticles and plants. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVKmsrrF&md5=51eba7f84e29e60f8d984c811aa47fb8
- 90 Oves, M. ; Aslam, M. ; Rauf, M. A. ; Qayyum, S. ; Qari, H. A. ; Khan, M. S. ; Alam, M. Z. ; Tabrez, S. ; Pugazhendhi, A. ; Ismail, I. M. I. Antimicrobial and Anticancer Activities of Silver Nanoparticles Synthesized from the Root Hair Extract of Phoenix Dactylifera . Materials Science and Engineering: C 2018 , 89 , 429 – 443 , DOI: 10.1016/j.msec.2018.03.035 90 Antimicrobial and anticancer activities of silver nanoparticles synthesized from the root hair extract of Phoenix dactylifera Oves, Mohammad; Aslam, Mohammad; Rauf, Mohd. Ahmar; Qayyum, Shariq; Qari, Huda A.; Khan, Mohd. Shahnawaz; Alam, Mohammad Zubair; Tabrez, Shams; Pugazhendhi, Arivalagan; Ismail, Iqbal M. I. Materials Science & Engineering, C: Materials for Biological Applications ( 2018 ), 89 ( ), 429-443 CODEN: MSCEEE ; ISSN: 0928-4931 . ( Elsevier B.V. ) There is a continuous rise in the rate of medicine consumption because of the development of drug resistance by microbial pathogens. In the last one decade, silver nanoparticles (AgNPs) have become a remarkable choice for the development of new drugs due to their excellent broad-spectrum antimicrobial activity. In the current piece of work, we have synthesized AgNPs from the root ext. of Phoenix dactylifera to test their antimicrobial and anti-cancer potential. UV-visible spectra showed the surface plasmon resonance peak at 420 nm λmax corresponding to the formation of silver nanoparticles, FTIR spectra further confirmed the involvement of biol. moieties in AgNPs synthesis. Moreover, XRD anal. showed the cryst. nature of AgNPs and predicted the crystallite size of 15 to 40 nm. Electron microscopy analyses confirmed their spherical shape. In addn., synthesized AgNPs was also found to control the growth of C. albicans and E. coli on solid nutrient medium with 20 and 22 mm zone of inhibition, resp. The 100% potency at 40μg/mL AgNPs concn. was obsd. against E. coli and C. albicans after 4 h and 48 h incubation resp. Importantly, AgNPs were also found to decrease the cell viability of MCF7 cell lines in vitro with IC50 values of 29.6μg/mL and could act as a controlling agent of human breast cancer. Based on our results, we conclude that biol. synthesized AgNPs exhibited multifunctional properties and could be used against human cancer and other infectious diseases. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXosFSqt74%253D&md5=7ddd515aa4039ae844cdf5f7285e8164
- 91 Nakhjavani, M. ; Nikkhah, V. ; Sarafraz, M. M. ; Shoja, S. ; Sarafraz, M. Green Synthesis of Silver Nanoparticles Using Green Tea Leaves: Experimental Study on the Morphological, Rheological and Antibacterial Behaviour . Heat Mass Transfer 2017 , 53 , 3201 – 3209 , DOI: 10.1007/s00231-017-2065-9 91 Green synthesis of silver nanoparticles using green tea leaves: Experimental study on the morphological, rheological and antibacterial behaviour Nakhjavani, Maryam; Nikkhah, V.; Sarafraz, M. M.; Shoja, Saeed; Sarafraz, Marzieh Heat and Mass Transfer ( 2017 ), 53 ( 10 ), 3201-3209 CODEN: HMTRF8 ; ISSN: 0947-7411 . ( Springer ) In this paper, silver nanoparticles are produced via green synthesis method using green tea leaves. The introduced method is cost-effective and available, which provides condition to manipulate and control the av. nanoparticle size. The produced particles were characterized using x-ray diffraction, scanning electron microscopic images, UV visualization, digital light scattering, zeta potential measurement and thermal cond. measurement. Results demonstrated that the produced samples of silver nanoparticles are pure in structure (based on the x-ray diffraction test), almost identical in terms of morphol. (spherical and to some extent cubic) and show longer stability when dispersed in deionized water. The UV-visualization showed a peak in 450 nm, which is in accordance with the previous studies reported in the literature. Results also showed that small particles have higher thermal and antimicrobial performance. As green tea leaves are used for extg. the silver nanoparticles, the method is eco-friendly. The thermal behavior of silver nanoparticle was also analyzed by dispersing the nanoparticles inside the deionized water. Results showed that thermal cond. of the silver nano-fluid is higher than that of obtained for the deionized water. Activity of Ag nanoparticles against some bacteria was also examd. to find the suitable antibacterial application for the produced particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpsV2qurk%253D&md5=7e6c7b1bc7664cc1e1c6834c048fec48
- 92 Sastry, M. ; Patil, V. ; Sainkar, S. R. Electrostatically Controlled Diffusion of Carboxylic Acid Derivatized Silver Colloidal Particles in Thermally Evaporated Fatty Amine Films . J. Phys. Chem. B 1998 , 102 , 1404 – 1410 , DOI: 10.1021/jp9719873 92 Electrostatically Controlled Diffusion of Carboxylic Acid Derivatized Silver Colloidal Particles in Thermally Evaporated Fatty Amine Films Sastry, Murali; Patil, Vijaya; Sainkar, S. R. Journal of Physical Chemistry B ( 1998 ), 102 ( 8 ), 1404-1410 CODEN: JPCBFK ; ISSN: 1089-5647 . ( American Chemical Society ) It was recently demonstrated that carboxylic acid derivatized silver colloidal particles can be incorporated in thermally evapd. fatty amine films by immersion of the films in the silver sol and that the process is controlled through electrostatic interactions (M. Sastry et. al. (1997)). In this paper, the influence of colloidal particle concn., soln. pH, and film thickness on the kinetics of cluster incorporation in thermally evapd. fatty amine films is analyzed from quartz-crystal microgravimetry (QCM) measurements in terms of a one-dimensional (1-D) Fickian-type diffusion model. Although it is found that 1-D diffusion adequately represents the cluster mass uptake kinetics obsd. using QCM, an interesting film-thickness dependence on the diffusivity was obsd. The nature of the cluster-diffusion curves were quite different for amine films annealed prior to immersion in the colloidal soln. In these cases, the 1-D-diffusion model with a single diffusivity fails, indicating the possible occurrence of addnl. diffusion channels for cluster incorporation. In situ QCM and optical absorption spectroscopy measurements have been made to elucidate the mechanism for cluster diffusion in the thermally evapd. films. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFyjtw%253D%253D&md5=71aededc0f5b3306bf916ddf9993732d
- 93 Henglein, A. Physicochemical Properties of Small Metal Particles in Solution: “Microelectrode” Reactions, Chemisorption, Composite Metal Particles, and the Atom-to-Metal Transition . J. Phys. Chem. 1993 , 97 , 5457 – 5471 , DOI: 10.1021/j100123a004 93 Physicochemical properties of small metal particles in solution: "microelectrode" reactions, chemisorption, composite metal particles, and the atom-to-metal transition Henglein, Arnim Journal of Physical Chemistry ( 1993 ), 97 ( 21 ), 5457-71 CODEN: JPCHAX ; ISSN: 0022-3654 . The study of nanometer and subnanometer colloidal metal particles in aq. soln. complements the study of small particles in mol. beams, frozen solns., and inorg. clusters. The electronic properties of the metal particles are changed by surface modification, for example by chemisorption of a nucleophilic mol. or by deposition of a 2nd metal. The resulting changes in the chem., photochem., and optical properties are discussed. Methods are described which enable one to store excess electrons or pos. holes on the particles in a controlled manner and to study the accompanying changes in the optical properties. Metal particles carrying excess electrons initiate electrochem. reactions such as the redn. of H2O or the deposition of metals. Concentric bimetallic and trimetallic particles can be synthesized this way. The transition from the atom to the metal can be studied by pulse radiolysis: a known concn. of atom is generated by a pulse and the development of the metal absorption spectrum is then recorded as a function of time as the atoms coalesce to yield larger particles. It is often obsd. that the absorption spectrum of the metal is reached after only a few coalescence steps, i.e. at agglomeration nos. of ∼10. In the case of Ag, 2 magic clusters which are not metallic and having long lifetimes (100 s and 15 min) are obsd. during the coalescence. These clusters have giant absorption bands at wavelengths distinctly shorter than that of the 380-nm plasmon band of metallic Ag particles. The clusters live for hours and days in the presence of polyanions. They have reducing properties and also react eagerly with nucleophilic reagents. They can be fragmented upon illumination and photoemit electrons with quantum yields >0.1. The dependence of the std. redox potential on particle size is also discussed. The atom-to-metal transition manifests itself also in the colloid chem. properties of metal particle (transition from complex formation with anions of oligomeric clusters to double layer formation around larger particles). 80 Refs. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXisVChurc%253D&md5=d44f6b41d652cd508f10fed199c1e443
- 94 Sastry, M. ; Mayya, K. S. ; Bandyopadhyay, K. PH Dependent Changes in the Optical Properties of Carboxylic Acid Derivatized Silver Colloidal Particles . Colloids Surf., A 1997 , 127 , 221 – 228 , DOI: 10.1016/S0927-7757(97)00087-3 94 pH dependent changes in the optical properties of carboxylic acid derivatized silver colloidal particles Sastry, Murali; Mayya, K. S.; Bandyopadhyay, K. Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 1997 ), 127 ( 1-3 ), 221-228 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier ) The optical properties of Ag colloidal particles derivatized using an arom. bifunctional mol., 4-carboxythiophenol, are presented. The capping mol. forms a thiolate bond with the Ag colloidal particle yielding a carboxylic acid terminal functionality which may then be charged to varying degrees by controlling the Ag hydrosol pH. A progressive red shift together with a damping and broadening of the surface plasmon feature (λmax) of the Ag particles is obsd. as the pH is reduced 10-3. Ag colloidal particles with high surface coverage of the bifunctional mol. showed negligible flocculation with time at high soln. pH indicating good stabilization due to Coulombic repulsive interactions. At low pH, considerable flocculation was obsd. even for high surface coverage due to lack of Coulombic stabilization. A tentative explanation is put forward to explain changes in the optical properties of the colloidal particles due to variation in the pH dependent surface charge of the particles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXltFSrs7c%253D&md5=e89fa76e92941d2bf292c0d36a525e27
- 95 Sultana, N. ; Raul, P. K. ; Goswami, D. ; Das, D. ; Islam, S. ; Tyagi, V. ; Das, B. ; Gogoi, H. K. ; Chattopadhyay, P. ; Raju, P. S. Bio-Nanoparticle Assembly: A Potent on-Site Biolarvicidal Agent against Mosquito Vectors . RSC Adv. 2020 , 10 , 9356 – 9368 , DOI: 10.1039/C9RA09972G 95 Bio-nanoparticle assembly: a potent on-site biolarvicidal agent against mosquito vectors Sultana, Nazima; Raul, Prasanta K.; Goswami, Diganta; Das, Dipankar; Islam, Saidul; Tyagi, Varun; Das, Bodhaditya; Gogoi, Hemanta K.; Chattopadhyay, Pronobesh; Raju, Pakalapati S. RSC Advances ( 2020 ), 10 ( 16 ), 9356-9368 CODEN: RSCACL ; ISSN: 2046-2069 . ( Royal Society of Chemistry ) Vector-borne diseases such as malaria, dengue, yellow fever, encephalitis and filariasis are considered serious human health concerns in the field of medical entomol. Controlling the population of mosquito vectors is one of the best strategies for combating such vector-borne diseases. However, the use of synthetic insecticides for longer periods of time increases mosquito resistance to the insecticides. Recently, the search for new environmentally friendly and efficient insecticides has attracted major attention globally. With the evolution of material sciences, researchers have reported the effective control of such diseases using various sustainable resources. The present investigation demonstrates a potent on-site biolarvicidal agent against different mosquito vectors such as Aedes albopictus, Anopheles stephensi and Culex quinquefasciatus. Stable and photo-induced colloidal silver nanoparticles were generated via the surface functionalization of the root ext. of Cyprus rotundas. Characterizations of the nanoparticles were performed using assorted techniques, such as UV-visible spectroscopy, FTIR spectroscopy, DLS and HRTEM. The bioefficacy of the synthesized nanoparticles was investigated against different species of mosquito larvae through the evaluation of their life history trait studies, fecundity and hatchability rate of the treated larvae. Histopathol. and polymerase chain reaction-random amplified polymorphic DNA (RAPD) analyses of the treated larvae were also examd. to establish the cellular damage. The synthesized nanoparticles showed remarkable larvicidal activity against mosquito larvae in a very low concn. range (0.001-1.00) mg L-1. The histopathol. study confirmed that the present nanoparticles could easily enter the cuticle membrane of mosquito larvae and subsequently obliterate their complete intestinal system. Furthermore, RAPD anal. of the treated larvae could assess the damage of the DNA banding pattern. The present work demonstrates a potent biolarvicidal agent using sustainable bioresources of the aq. Cyprus rotundas root ext. The results showed that the synthesized nanoparticles were stable under different physiol. conditions such as temp. and photo-induced oxidn. The effectiveness of these materials against mosquito larvae was quantified at very low dose concns. The present biolarvicidal agent can be considered as an environmentally benign material to control the mosquito vectors with an immense potential for on-site field applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksVWgtro%253D&md5=aefb44759eae426f0b19f2c19714e85e
- 96 Alomar, T. S. ; AlMasoud, N. ; Awad, M. A. ; El-Tohamy, M. F. ; Soliman, D. A. An Eco-Friendly Plant-Mediated Synthesis of Silver Nanoparticles: Characterization, Pharmaceutical and Biomedical Applications . Mater. Chem. Phys. 2020 , 249 , 123007 , DOI: 10.1016/j.matchemphys.2020.123007 96 An eco-friendly plant-mediated synthesis of silver nanoparticles: Characterization, pharmaceutical and biomedical applications Alomar, Taghrid S.; AlMasoud, Najla; Awad, Manal A.; El-Tohamy, Maha F.; Soliman, Dina A. Materials Chemistry and Physics ( 2020 ), 249 ( ), 123007 CODEN: MCHPDR ; ISSN: 0254-0584 . ( Elsevier B.V. ) The current study focused on green chem. approach to synthesize eco-friendly AgNPs using an aq. ext. of Peganum harmala leaves. The formed AgNPs were characterized using different spectroscopic and microscopic analyses: UV-visible spectrophotometry (UV-Vis), Fluorolog 3 spectrometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier transform IR spectroscopy (FTIR), techniques using a Zetasizer. The resulted nanoparticles were screened for their biomedical and pharmaceutical properties. They investigated for antimicrobial activity against various strains of bacteria and fungi. The synthesized AgNPs showed a higher antibacterial potential against Gram neg. pathogen E. coli with inhibition zone of 65 mm rather than both Gram pos. pathogens S. aureus and B. cereus of inhibition zone 50 mm. Meanwhile, no inhibition zone was obsd. for E. faecalis. Furthermore, the formed AgNPs were applied to enhance the sensitivity and selectivity of the spectrophotometric detn. of the antibiotic Rifaximin in bulk powder or tablet form with a λmax of 340 nm. The proposed spectrophotometric technique for detg. Rifaximin in the presence of silver nanoparticles showed a linear relationship in the concn. ranges of 5-80μg/mL and followed the linear regression equation A = 0.039C-0.166 (r = 0.9997), with low limits of detection and quantification of 1.75 and 5.0μg mL -1, resp. According to the ICH guidelines, the proposed technique was validated. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXmslehtrY%253D&md5=5cdefd726312e68607f350db46eb6ec3
- 97 Varghese Alex, K. ; Tamil Pavai, P. ; Rugmini, R. ; Shiva Prasad, M. ; Kamakshi, K. ; Sekhar, K. C. Green Synthesized Ag Nanoparticles for Bio-Sensing and Photocatalytic Applications . ACS Omega 2020 , 5 , 13123 – 13129 , DOI: 10.1021/acsomega.0c01136 97 Green Synthesized Ag Nanoparticles for Bio-Sensing and Photocatalytic Applications Varghese Alex, Kevin; Tamil Pavai, Parthiban; Rugmini, Radhasaran; Shiva Prasad, Madavi; Kamakshi, Koppole; Sekhar, Koppole Chandra ACS Omega ( 2020 ), 5 ( 22 ), 13123-13129 CODEN: ACSODF ; ISSN: 2470-1343 . ( American Chemical Society ) In this work, sensing and photocatalytic activities of green synthesized silver nanoparticles (Ag NPs) are investigated. Ag NPs have been synthesized by the redn. of silver nitrate (AgNO3) using different leaf exts. An optimum surface plasmon resonance (SPR) behavior is obtained for neem leaf exts. because of the presence of a high concn. of diterpenoids, as evidenced from gas chromatog. mass spectroscopy results. The underlying mechanism for the formation of Ag NPs is highlighted. The Ag NPs are in spherical shape and exhibit the hexagonal crystal phase and also show a good stability. The biosensing property of the Ag NPs is evaluated using mancozeb (MCZ) agro-fungicide, and the SPR peak position exhibited a linear response with MCZ concn. The sensitivity is found to be 39.1 nm/mM. Further, the photocatalytic activity of Ag NPs is tested using 0.5 mM MCZ soln. as a model under UV-visible illumination. It is obsd. that photocatalytic activity is caused by the formation of reactive oxygen species. Therefore, the green synthesized Ag NPs are potential candidates for biosensing and photocatalytic applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtVSgtL7J&md5=9643816f01b12ca04c9b4dec53682bad
- 98 Parit, S. B. ; Karade, V. C. ; Patil, R. B. ; Pawar, N. v. ; Dhavale, R. P. ; Tawre, M. ; Pardesi, K. ; Jadhav, U. U. ; Dawkar, V. v. ; Tanpure, R. S. ; Kim, J. H. ; Jadhav, J. P. ; Chougale, A. D. Bioinspired Synthesis of Multifunctional Silver Nanoparticles for Enhanced Antimicrobial and Catalytic Applications with Tailored SPR Properties . Mater. Today Chem. 2020 , 17 , 100285 , DOI: 10.1016/j.mtchem.2020.100285 98 Bioinspired synthesis of multifunctional silver nanoparticles for enhanced antimicrobial and catalytic applications with tailored SPR properties Parit, S. B.; Karade, V. C.; Patil, R. B.; Pawar, N. V.; Dhavale, R. P.; Tawre, M.; Pardesi, K.; Jadhav, U. U.; Dawkar, V. V.; Tanpure, R. S.; Kim, J. H.; Jadhav, J. P.; Chougale, A. D. Materials Today Chemistry ( 2020 ), 17 ( ), 100285 CODEN: MTCAD8 ; ISSN: 2468-5194 . ( Elsevier Ltd. ) In the developing nanotechnol. world, numerous attempts have been made to prep. the nobel metallic nanoparticles (NPs), which can improve their applicability in diverse fields. In the present work, the biosynthesis of silver (Ag) NPs has been successfully achieved through the medicinal plant ext. (PE) of G. resinifera and effectively used for the catalytic and antibacterial applications. The size dependant tuneable surface plasmon resonance (SPR) properties attained through altering precursor concns. The X-ray and selected area diffraction pattern for Ag NPs revealed the high cryst. nature of pure Ag NPs with dominant (111) phase. Accordingly, the dual-band SPR spectrum is situated in the UV-Vis spectra validating the non-spherical shape of Ag NPs. The functional group present on the Ag NPs surface was analyzed by FT-IR confirms the capping and reducing ability of methanolic PE G. resinifera. Further, the mechanism of antimicrobial activity studied using electron microscope showed the morphol. changes with destructed cell walls of E. coli NCIM 2931 and S. aureus NCIM 5021 cells, when they treated with Ag NPs. The Ag NPs were more effective against S. aureus and E. coli with MIC 128μg/mL as compared to P. aeruginosa NCIM 5029 with MIC 256μg/mL. Apart from this, the redn. of toxic org. pollutant 4-NP to 4-AP within 20 min reveals the excellent catalytic activity of Ag NPs with rate const. k = 15.69 s-1. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtFCju7bL&md5=95db3ecc85a7246d73998d7a38eaebe9
- 99 Barchi, J., Jr. Introduction to Comprehensive Glycoscience: The Good, the Better and What’s to Come ; Elsevier Science , 2021 ; pp 1 – 20 . There is no corresponding record for this reference.
- 100 De Roo, J. ; Yazdani, N. ; Drijvers, E. ; Lauria, A. ; Maes, J. ; Owen, J. S. ; van Driessche, I. ; Niederberger, M. ; Wood, V. ; Martins, J. C. ; Infante, I. ; Hens, Z. Probing Solvent-Ligand Interactions in Colloidal Nanocrystals by the NMR Line Broadening . Chem. Mater. 2018 , 30 , 5485 – 5492 , DOI: 10.1021/acs.chemmater.8b02523 100 Probing Solvent-Ligand Interactions in Colloidal Nanocrystals by the NMR Line Broadening De Roo, Jonathan; Yazdani, Nuri; Drijvers, Emile; Lauria, Alessandro; Maes, Jorick; Owen, Jonathan S.; Van Driessche, Isabel; Niederberger, Markus; Wood, Vanessa; Martins, Jose C.; Infante, Ivan; Hens, Zeger Chemistry of Materials ( 2018 ), 30 ( 15 ), 5485-5492 CODEN: CMATEX ; ISSN: 0897-4756 . ( American Chemical Society ) Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation, and assembly, there is currently no direct method to study this. Here the authors examine the broadening of 1H NMR resonances assocd. with bound ligands and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. The line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent, and the latter results from solvent-ligand interactions. The authors' model is supported by exptl. and theor. evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide, and selenide nanocrystals. The authors' findings thus put forward NMR line-shape anal. as an indispensable tool to form, study, and manipulate nanocolloids. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhsVeit7rF&md5=3f4ad127ad928d05b4b89d906ee03730
- 101 Fiurasek, P. ; Reven, L. Phosphonic and Sulfonic Acid-Functionalized Gold Nanoparticles: A Solid-State NMR Study . Langmuir 2007 , 23 , 2857 – 2866 , DOI: 10.1021/la0629781 101 Phosphonic and Sulfonic Acid-Functionalized Gold Nanoparticles: A Solid-State NMR Study Fiurasek, Petr; Reven, Linda Langmuir ( 2007 ), 23 ( 5 ), 2857-2866 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Gold nanoparticles capped with 11-mercaptoundecanylphosphonic acid (MUP) and sodium 10-mercaptodecanesulfonic acid (MDS) were characterized by a range of techniques which included solid-state 31P and 13C NMR spectroscopies. Despite similar core sizes and alkyl chain lengths, the conformational and dynamic properties of the capping ligands are very different for the two types of nanoparticles. Whereas MDS produces disordered monolayers on planar gold surfaces, the MDS-capped nanoparticles show a high degree of chain order with the onset of reversible chain disordering occurring just above room temp. The alkyl chains of MUP adsorbed on the gold nanoparticles are more ordered and motionally restricted than the unbound solid surfactant due to strong intramonolayer and interparticle hydrogen bonds. This conformational order is thermally stable, and disordering only occurs upon decompn. and desorption of MUP from the gold core. Solid-state 31P NMR is a sensitive probe of the interactions of the PO3H2 terminal groups. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXktF2luw%253D%253D&md5=4b26e299d334dad3b4ed31e2cf0b6048
- 102 Sadasivan, S. ; Khushalani, D. ; Mann, S. Synthesis and Shape Modification of Organo-Functionalised Silica Nanoparticles with Ordered Mesostructured Interiors . J. Mater. Chem. 2003 , 13 , 1023 – 1029 , DOI: 10.1039/b300851g 102 Synthesis and shape modification of organo-functionalized silica nanoparticles with ordered mesostructured interiors Sadasivan, Sajanikumari; Khushalani, Deepa; Mann, Stephen Journal of Materials Chemistry ( 2003 ), 13 ( 5 ), 1023-1029 CODEN: JMACEP ; ISSN: 0959-9428 . ( Royal Society of Chemistry ) Organo-functionalized MCM-41 nanoparticles have been prepd. by a diln./neutralisztion method involving the surfactant-templated co-condensation of 3-aminopropyltriethoxysilane, allyltriethoxysilane or 3-mercaptopropyltriethoxysilane with tetraethoxysilane under alk. conditions. The presence of covalently coupled org. groups within the hexagonally ordered silica mesophase was confirmed by solid-state 13C and 29Si MAS NMR spectroscopy. TEM studies show that amine- and allyl-functionalized nanoparticles are single-domain oblate ellipsoidal crystals, in which the cylindrical micelles are aligned parallel to the morphol. minor axis. In contrast, the thiol-functionalized nanoparticles were synthesized in the form of nanofilaments elongated specifically along the channel direction of the MCM-41 hexagonal mesostructure. A mechanism is proposed in which changes in the nanoparticle morphol. are attributed predominantly to an increase in surface charge assocd. with the anionic mercaptopropyl groups that inhibits the side-on attachment of silica-surfactant micelles to partially ordered primary nanoclusters. In contrast, nanoparticles with neutral side chains, such as amino and allyl moieties, as well as unfunctionalized MCM-41, develop by side-on attachment to radially arranged defect sites of a modulated hexagonal mesophase assocd. with the oblate ellipsoidal morphol. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXjtVCntLY%253D&md5=b79a42eccccbe2c22a25a31258646890
- 103 Marbella, L. E. ; Millstone, J. E. NMR Techniques for Noble Metal Nanoparticles . Chem. Mater. 2015 , 27 , 2721 – 2739 , DOI: 10.1021/cm504809c 103 NMR Techniques for Noble Metal Nanoparticles Marbella, Lauren E.; Millstone, Jill E. Chemistry of Materials ( 2015 ), 27 ( 8 ), 2721-2739 CODEN: CMATEX ; ISSN: 0897-4756 . ( American Chemical Society ) Soln. phase noble metal nanoparticle growth reactions are comprised of deceptively simple steps. Anal. methods with high chem., spatial, and temporal resoln. are crucial to understanding these reactions and subsequent nanoparticle properties. However, approaches for the characterization of solid inorg. materials and soln. phase mol. species are often disparate. One powerful technique to address this gap is NMR spectroscopy, which can facilitate routine, direct, mol.-scale anal. of nanoparticle formation and morphol. in situ, in both the soln. and the solid phase. A growing body of work indicates that NMR analyses should yield an exciting complement to the existing canon of routine nanoparticle characterization methods such as electron microscopy and optical absorption spectroscopy. Recent developments in the application of NMR techniques to the study of noble metal nanoparticle growth, surface chem., and phys. properties are discussed. Specifically, the authors describe the unique capabilities of NMR in resolving hard-soft matter interfaces with both high chem. and high spatial resoln. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkt1Oisbs%253D&md5=3d84a29057d3d85506d74308e1a6f189
- 104 Li, Y. ; Jin, R. Seeing Ligands on Nanoclusters and in Their Assemblies by X-Ray Crystallography: Atomically Precise Nanochemistry and Beyond . J. Am. Chem. Soc. 2020 , 142 , 13627 – 13644 , DOI: 10.1021/jacs.0c05866 104 Seeing Ligands on Nanoclusters and in Their Assemblies by X-ray Crystallography: Atomically Precise Nanochemistry and Beyond Li, Yingwei; Jin, Rongchao Journal of the American Chemical Society ( 2020 ), 142 ( 32 ), 13627-13644 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A review. Ligands are of tremendous importance for colloidal nanoparticles (NPs) in terms of surface protection, size and shape control, tailoring properties, self-assembly, and applications. However, it is very challenging to obtain unambiguous information on the ligands and their interactions and patterning on NPs. The recent advent of atomically precise nanochem. has opened new horizons. One can now see ligands with at. resoln. and understand their behavior on the surface of ultrasmall NPs (1-3 nm) and also in their assemblies. Such atomically precise NPs (or nanoclusters, NCs) bridge up with conventional NPs by providing unprecedented opportunities to reveal the specific patterns formed by intra- and inter-particle ligand interactions. In this Perspective, we first discuss how to achieve atomically precise NCs and det. their total structures. Then, we highlight the intra-particle ligand interactions (i.e., the ligand shell), including the various patterns formed on the NCs, the ligand patterning modes on facets and edges, and some aesthetic patterns assembled by ligands that are akin to biomol. organization. The inter-particle ligand interactions and their roles in directing the self-assembly of NCs into coherent superlattices are also discussed, which provides a deep understanding of assembly mechanisms, with the insights from atomically precise NCs hinting for the assembly of conventional NPs. Overall, the success in achieving atomically precise NCs is expected to bring new opportunities to fields beyond nanochem., esp. to materials design, engineering, and applications. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlyjsr%252FN&md5=c3b785e350fec39a04a943427415f730
- 105 Sakthivel, N. A. ; Shabaninezhad, M. ; Sementa, L. ; Yoon, B. ; Stener, M. ; Whetten, R. L. ; Ramakrishna, G. ; Fortunelli, A. ; Landman, U. ; Dass, A. The Missing Link: Au191(SPh- TBu)66Janus Nanoparticle with Molecular and Bulk-Metal-like Properties . J. Am. Chem. Soc. 2020 , 142 , 15799 – 15814 , DOI: 10.1021/jacs.0c05685 105 The Missing Link: Au191(SPh-tBu)66 Janus Nanoparticle with Molecular and Bulk-Metal-like Properties Sakthivel, Naga Arjun; Shabaninezhad, Masoud; Sementa, Luca; Yoon, Bokwon; Stener, Mauro; Whetten, Robert L.; Ramakrishna, Guda; Fortunelli, Alessandro; Landman, Uzi; Dass, Amala Journal of the American Chemical Society ( 2020 ), 142 ( 37 ), 15799-15814 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) Understanding the evolution of the structure and properties in metals from mol.-like to bulk-like was a long sought fundamental question in science, since Faraday's 1857 work. The authors report the discovery of a Janus nanomol., Au191(SPh-tBu)66 having both mol. and metallic characteristics, explored crystallog. and optically and modeled theor. Au191 has an anisotropic, singly twinned structure with an Au155 core protected by a ligand shell made of 24 monomeric [-S-Au-S-] and 6 dimeric [-S-Au-S-Au-S-] staples. The Au155 core is composed of an 89-atom inner core and 66 surface atoms, arranged as [Au3@Au23@Au63]@Au66 concentric shells of atoms. The inner core has a monotwinned/stacking-faulted fcc. structure. Structural evolution in metal nanoparticles was known to progress from multiply twinned, icosahedral, structures in smaller mol. sizes to untwinned bulk-like fcc. monocryst. nanostructures in larger nanoparticles. The monotwinned inner core structure of the ligand capped Au191 nanomol. provides the crit. missing link, and bridges the size-evolution gap between the mol. multiple-twinning regime and the bulk-metal-like particles with untwinned fcc. structure. The Janus nature of the nanoparticle is demonstrated by its optical and electronic properties, with metal-like electron-phonon relaxation and mol.-like long-lived excited states. First-principles theor. explorations of the electronic structure uncovered electronic stabilization through the opening of a shell-closing gap at the top of the occupied manifold of the delocalized electronic superatom spectrum of the inner core. The electronic stabilization together with the inner core geometric stability and the optimally stapled ligand-capping anchor and secure the stability of the entire nanomol. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhslant7vP&md5=a2178d30533b0730e3b1a9e93b6066ab
- 106 Sapsford, K. E. ; Tyner, K. M. ; Dair, B. J. ; Deschamps, J. R. ; Medintz, I. L. Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques . Anal. Chem. 2011 , 83 , 4453 – 4488 , DOI: 10.1021/ac200853a 106 Analyzing Nanomaterial Bioconjugates: A Review of Current and Emerging Purification and Characterization Techniques Sapsford, Kim E.; Tyner, Katherine M.; Dair, Benita J.; Deschamps, Jeffrey R.; Medintz, Igor L. Analytical Chemistry (Washington, DC, United States) ( 2011 ), 83 ( 12 ), 4453-4488 CODEN: ANCHAM ; ISSN: 0003-2700 . ( American Chemical Society ) A review with major sections on purifn., characterization (sepn. techniques, scattering techniques, microscopy, and spectroscopy), modeling, and emerging technologies and instrumentation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXls1ekt7w%253D&md5=0a45ab29e7a9e9003899247720acd8e5
- 107 Cao, G. ; Wang, Y. Characterization and Properties of Nanomaterials . Nanostructures and Nanomaterials 2011 , 433 – 508 , DOI: 10.1142/9789814340571_0008 There is no corresponding record for this reference.
- 108 Chapman, H. N. ; Fromme, P. ; Barty, A. ; White, T. A. ; Kirian, R. A. ; Aquila, A. ; Hunter, M. S. ; Schulz, J. ; Deponte, D. P. ; Weierstall, U. Femtosecond X-Ray Protein Nanocrystallography . Nature 2011 , 470 , 73 – 77 , DOI: 10.1038/nature09750 108 Femtosecond X-ray protein nanocrystallography Chapman, Henry N.; Fromme, Petra; Barty, Anton; White, Thomas A.; Kirian, Richard A.; Aquila, Andrew; Hunter, Mark S.; Schulz, Joachim; DePonte, Daniel P.; Weierstall, Uwe; Doak, R. Bruce; Maia, Filipe R. N. C.; Martin, Andrew V.; Schlichting, Ilme; Lomb, Lukas; Coppola, Nicola; Shoeman, Robert L.; Epp, Sascha W.; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Holl, Peter; Liang, Mengning; Barthelmess, Miriam; Caleman, Carl; Boutet, Sebastien; Bogan, Michael J.; Krzywinski, Jacek; Bostedt, Christoph; Bajt, Sasa; Gumprecht, Lars; Rudek, Benedikt; Erk, Benjamin; Schmidt, Carlo; Hoemke, Andre; Reich, Christian; Pietschner, Daniel; Strueder, Lothar; Hauser, Guenter; Gorke, Hubert; Ullrich, Joachim; Herrmann, Sven; Schaller, Gerhard; Schopper, Florian; Soltau, Heike; Kuehnel, Kai-Uwe; Messerschmidt, Marc; Bozek, John D.; Hau-Riege, Stefan P.; Frank, Matthias; Hampton, Christina Y.; Sierra, Raymond G.; Starodub, Dmitri; Williams, Garth J.; Hajdu, Janos; Timneanu, Nicusor; Seibert, M. Marvin; Andreasson, Jakob; Rocker, Andrea; Joensson, Olof; Svenda, Martin; Stern, Stephan; Nass, Karol; Andritschke, Robert; Schroeter, Claus-Dieter; Krasniqi, Faton; Bott, Mario; Schmidt, Kevin E.; Wang, Xiaoyu; Grotjohann, Ingo; Holton, James M.; Barends, Thomas R. M.; Neutze, Richard; Marchesini, Stefano; Fromme, Raimund; Schorb, Sebastian; Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Andersson, Inger; Hirsemann, Helmut; Potdevin, Guillaume; Graafsma, Heinz; Nilsson, Bjoern; Spence, John C. H. Nature (London, United Kingdom) ( 2011 ), 470 ( 7332 ), 73-77 CODEN: NATUAS ; ISSN: 0028-0836 . ( Nature Publishing Group ) X-ray crystallog. provides the vast majority of macromol. structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been detd. despite their importance in all living cells. Here we present a method for structure detn. where single-crystal X-ray diffraction snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (∼200 nm to 2 μm in size). We mitigate the problem of radiation damage in crystallog. by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure detn. of macromols. that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsVyguro%253D&md5=0fc5b6f7c78cf49893dc15704db706a7
- 109 Majeed Khan, M. A. ; Kumar, S. ; Ahamed, M. ; Alrokayan, S. A. ; AlSalhi, M. S. Structural and Thermal Studies of Silver Nanoparticles and Electrical Transport Study of Their Thin Films . Nanoscale Res. Lett. 2011 , 6 , 1 – 8 , DOI: 10.1186/1556-276X-6-434 There is no corresponding record for this reference.
- 110 Upadhyay, S. ; Parekh, K. ; Pandey, B. Influence of Crystallite Size on the Magnetic Properties of Fe3O4 Nanoparticles . J. Alloys Compd. 2016 , 678 , 478 – 485 , DOI: 10.1016/j.jallcom.2016.03.279 110 Influence of crystallite size on the magnetic properties of Fe3O4 nanoparticles Upadhyay, Sneha; Parekh, Kinnari; Pandey, Brajesh Journal of Alloys and Compounds ( 2016 ), 678 ( ), 478-485 CODEN: JALCEU ; ISSN: 0925-8388 . ( Elsevier B.V. ) Structural and magnetic properties of chem. synthesized magnetite nanoparticles have been studied using X-ray diffraction, Transmission Electron Microscopy and Vibrating Sample Magnetometer. Magnetically the synthesized nanoparticles are ranging from superparamagnetic to multi domain state. Av. crystallite size of the synthesized magnetite nanoparticles were detd. using X-ray line broadening and are found to be in the range of 9-53 nm. On the other hand, the TEM images show that the size is ranging between 7.9 and 200 nm with the transition from spherical superparamagnetic particles to faceted cubic multi domain particles. Magnetic parameters of the samples show a strong dependence on av. crystallite size. The ratio of coercive field at 20 K to that at 300 K (Hc (20 K)/Hc (300 K)) increased sharply with decrease in crystallite size. A crit. crystallite diam. of order 36 nm may be inferred as boundary between single domain to multi domain transition. Zero-field-cooled (ZFC) and field-cooled (FC) measurements at 10 Oe field validate the same for smallest and largest size samples, confirming that the anisotropy energy is greater than thermal energy up to 300 K temp. For 9 nm sample broad ZFC curve with overlapping of FC curve is obsd. just at 300 K, indicating the effect of strong dipolar field in superparamagnetic system. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmtVOlsL8%253D&md5=e98f4e353e1962bbcc19d27aa62c50ed
- 111 Fissan, H. ; Ristig, S. ; Kaminski, H. ; Asbach, C. ; Epple, M. Comparison of Different Characterization Methods for Nanoparticle Dispersions before and after Aerosolization . Anal. Methods 2014 , 6 , 7324 – 7334 , DOI: 10.1039/C4AY01203H 111 Comparison of different characterization methods for nanoparticle dispersions before and after aerosolization Fissan, Heinz; Ristig, Simon; Kaminski, Heinz; Asbach, Christof; Epple, Matthias Analytical Methods ( 2014 ), 6 ( 18 ), 7324-7334 CODEN: AMNEGX ; ISSN: 1759-9679 . ( Royal Society of Chemistry ) A well-known and accepted aerosol measurement technique, the scanning mobility particle sizer (SMPS), is applied to characterize colloidally dispersed nanoparticles. To achieve a transfer from dispersed particles to aerosolized particles, a newly developed nebulizer (N) is used that, unlike commonly used atomizers, produces significantly smaller droplets and therefore reduces the problem of the formation of residual particles. The capabilities of this new instrument combination (N + SMPS) for the anal. of dispersions were investigated, using three different dispersions, i.e. gold-PVP nanoparticles (∼20 nm), silver-PVP nanoparticles (∼70 nm) and their 1 : 1 (m : m) mixt. The results are compared to SEM measurements and two frequently applied techniques for characterizing colloidal systems: Dynamic light scattering (DLS) and anal. disk centrifugation (ADC). The differences, advantages and disadvantages of each method are discussed, esp. with respect to the size resoln. of the techniques and their ability to distinguish the particle sizes of the mixed dispersion. While DLS is, as expected, unable to resolve the binary dispersion, SEM, ADC and SMPS are able to give quant. information on the two particle sizes. However, while the high-resolving ADC is limited due to the dependency on a predefined d. of the investigated system, the transfer of dispersed particles into an aerosol and subsequent anal. with SMPS are an adequate way to characterize binary systems, independent of the d. of concerned particles, but matching the high resoln. of the ADC. We show that it is possible to use the well-established aerosol measurement technique (N + SMPS) in colloid science with all its advantages concerning size resoln. and accuracy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFOks7nO&md5=164ae5103811776a21db0a50f631f2c3
- 112 Surface Analysis Methods in Materials Science . In Springer Series in Surface Sciences ; O’Connor, D. J. , Sexton, B. A. , St, R. , Smart, C. , Eds.; Springer Berlin Heidelberg , 2003 . There is no corresponding record for this reference.
- 113 Veisi, H. ; Dadres, N. ; Mohammadi, P. ; Hemmati, S. Green Synthesis of Silver Nanoparticles Based on Oil-Water Interface Method with Essential Oil of Orange Peel and Its Application as Nanocatalyst for A3 Coupling . Materials Science and Engineering: C 2019 , 105 , 110031 , DOI: 10.1016/j.msec.2019.110031 113 Green synthesis of silver nanoparticles based on oil-water interface method with essential oil of orange peel and its application as nanocatalyst for A3 coupling Veisi, Hojat; Dadres, Nahid; Mohammadi, Pourya; Hemmati, Saba Materials Science & Engineering, C: Materials for Biological Applications ( 2019 ), 105 ( ), 110031 CODEN: MSCEEE ; ISSN: 0928-4931 . ( Elsevier B.V. ) Silver (Ag) nanoparticles (NPs) were prepd. through a biol. procedure where the essential oils of orange peel were used as a capper and reducing agent. Characterization of these Ag/EOs orange NPs was carried out using X-ray diffraction, Fourier transformed IR spectroscopy, field emission SEM, energy dispersive X-ray spectroscopy, transmission electron microscopy, UV-visible spectroscopy and thermogravimetric anal. (TGA). These NPs were utilized as an effective heterogeneous nanocatalyst for the three-component A3 coupling reaction of secondary amines, aldehydes and terminal alkynes for the synthesis of propargylamines RC≡CCH(R1)(NR2R3) [R = n-hexyl, Ph; R1 = n-Pr, Ph, 2-thienyl, etc.; R2 = R3 = Et, Bn; R2R3 = (CH2)4, (CH2)5, (CH2)2O(CH2)2]. Different ranges with high performance were achieved for propargylamines. Moreover, the isolation and recovery of Ag/EOs orange NPs was very easy, efficient and cost effective. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFWlsbbL&md5=1cb6409048149d381b81de2ba250b6e3
- 114 Yoo, J. ; So, H. ; Yang, M. H. ; Lee, K. J. Effect of Chloride Ion on Synthesis of Silver Nanoparticle Using Retrieved Silver Chloride as a Precursor from the Electronic Scrap . Appl. Surf. Sci. 2019 , 475 , 781 – 784 , DOI: 10.1016/j.apsusc.2019.01.032 114 Effect of chloride ion on synthesis of silver nanoparticle using retrieved silver chloride as a precursor from the electronic scrap Yoo, Juyeon; So, Hyeongsub; Yang, Min-Ho; Lee, Kun-Jae Applied Surface Science ( 2019 ), 475 ( ), 781-784 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) Retrieving silver from available resources, esp. the electronic scraps (E-scraps), is becoming more important due to increasing demand for electronic industry and rapid growth in disposal problems of the E-scraps. Although chem. leaching has been extensively employed to retrieve the silver, the purity issue still remains. In this work, the silver nanoparticles (Ag NPs) with high purity are synthesized using the retrieved silver chloride (AgCl) from the E-scraps via chem. leaching and selective pptn. These particles show an av. diam. of 68 nm and narrow size distribution. The effect of Cl- ions on particles synthesis are also investigated, resulting in variation in shape and size of particles due to selective etching and slow growth rate. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXpvF2jsg%253D%253D&md5=d697253d58440512ce985fa2ae98b494
- 115 Choma, J. ; Jamioła, D. ; Ludwinowicz, J. ; Jaroniec, M. Deposition of Silver Nanoparticles on Silica Spheres and Rods . Colloids Surf., A 2012 , 411 , 74 – 79 , DOI: 10.1016/j.colsurfa.2012.07.004 115 Deposition of silver nanoparticles on silica spheres and rods Choma, Jerzy; Jamiola, Dominik; Ludwinowicz, Jowita; Jaroniec, Mietek Colloids and Surfaces, A: Physicochemical and Engineering Aspects ( 2012 ), 411 ( ), 74-79 CODEN: CPEAEH ; ISSN: 0927-7757 . ( Elsevier B.V. ) Spherical and rod-like silica particles were used as cores to deposit shells of silver nanoparticles. Prior silver deposition the siliceous cores were modified with 3-aminopropyltrimetoxysilane to facilitate Ag deposition on the surface of silica particles. The process of Ag deposition was carried out in two consecutive steps: first, silver nanoparticles were deposited on the silica cores from silver nitrate soln. in the presence of ammonia and Sn2+ ions. Next, further deposition of silver was achieved by reducing silver cations with formaldehyde. This process led to the formation of a densely packed silver layer that consisted of non-uniform silver nanoparticles (size from several to about 100 nm), on the surface of spherical and rod-like siliceous cores. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFOmsb7F&md5=39360fb93184918c789fc1e3188dd3a6
- 116 Liu, K. G. ; Abbasi, A. R. ; Azadbakht, A. ; Hu, M. L. ; Morsali, A. Deposition of Silver Nanoparticles on Polyester Fiber under Ultrasound Irradiations . Ultrason. Sonochem. 2017 , 34 , 13 – 18 , DOI: 10.1016/j.ultsonch.2016.04.006 116 Deposition of silver nanoparticles on polyester fiber under ultrasound irradiations Liu, Kuan-Guan; Abbasi, Amir Reza; Azadbakht, Azadeh; Hu, Mao-Lin; Morsali, Ali Ultrasonics Sonochemistry ( 2017 ), 34 ( ), 13-18 CODEN: ULSOER ; ISSN: 1350-4177 . ( Elsevier B.V. ) The polyester fiber contg. Ag nanoparticles was prepd. through the chem. redn. under ultrasound irradn. Influences of redn. reagents on the morphol. properties of Ag nanoparticles@polyester fiber were studied. The sizes of metallic nanoparticles vary significantly with the types of redn. reagents used in the synthesis. A strong redn. reaction promotes a fast reaction rate and favors the formation of smaller nanoparticle. A weak redn. reagent induces a slow reaction rate and favors relatively larger particles. The products were investigated by means of SEM and X-ray powder diffraction (XRPD). >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XotV2gtL8%253D&md5=5b23a9f177fafc7601055d5a72551a6d
- 117 Shahid-ul-Islam ; Butola, B. S. ; Verma, D. Facile Synthesis of Chitosan-Silver Nanoparticles onto Linen for Antibacterial Activity and Free-Radical Scavenging Textiles . Int. J. Bio. Macromol. 2019 , 133 , 1134 – 1141 , DOI: 10.1016/j.ijbiomac.2019.04.186 117 Facile synthesis of chitosan-silver nanoparticles onto linen for antibacterial activity and free-radical scavenging textiles Shahid-ul-Islam; Butola, B. S.; Verma, Deepali International Journal of Biological Macromolecules ( 2019 ), 133 ( ), 1134-1141 CODEN: IJBMDR ; ISSN: 0141-8130 . ( Elsevier B.V. ) In this work, we present a straightforward and rapid green chem.-based method to fabricate chitosan-based silver nanoparticles onto linen fabric in the presence of pineapple crown ext. biomols. such as sucrose, fructose and glucose. The resultant nanoparticles were studied by UV-vis, TEM, EDX, and their coating onto linen was supported by results from SEM, EDX with mapping images, FTIR spectroscopy and TGA technique. This one step process yields spherical particles that are well dispersed and non-aggregated. Using chitosan polysaccharide, the coloring, antibacterial and radical scavenging activity of Ag nanoparticles (NPs) could be transferred to the linen fabric surface. Chitosan not only favors coating and stabilization of the silver ions, but synergistically with silver nanoparticles also exhibited strong antibacterial and antioxidant effects onto linen surface. The coloring properties of coated linen fabrics were measured in terms of CIELa*b* values using reflectance spectroscopy. The coated linen was also screened for their antibacterial activity against E. coli and S. aureus, while as antioxidant activity was investigated photometrically by DPPH assay. The results demonstrate that chitosan-silver nanoparticles can be used as safer and greener alternative to chem. functional agents currently being practiced. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXptVSktrc%253D&md5=09a90eb05c053f115df84b6cc69acf34
- 118 Yu, X. Y. ; Arey, B. ; Chatterjee, S. ; Chun, J. Improving in Situ Liquid SEM Imaging of Particles . Surf. Interface Anal. 2019 , 51 , 1325 – 1331 , DOI: 10.1002/sia.6700 118 Improving in situ liquid SEM imaging of particles Yu, Xiao-Ying; Arey, Bruce; Chatterjee, Sayandev; Chun, Jaehun Surface and Interface Analysis ( 2019 ), 51 ( 13 ), 1325-1331 CODEN: SIANDQ ; ISSN: 0142-2421 . ( John Wiley & Sons Ltd. ) This work presents in situ imaging of synthesized boehmite (γ-AlOOH) particles ranging from 20 to 100 nm, suspended in liq., in a vacuum compatible microfluidic sample holder using a SEM under the high vacuum mode and highlights the advantage of in situ liq. imaging of colloids. Nanometer-sized boehmite particles in high-level radioactive wastes at the Hanford site are known to be difficult to dissolve and cause rheol. problems for processing in the nuclear waste treatment plant. Therefore, it is important to characterize boehmite particles and understand how they form aggregates in the liq. state. Several tech. advancements are made to optimize in situ liq. SEM chem. imaging resulting in the improved ability to obtain secondary electron (SE), backscattered electron (BSE) images, and energy dispersive X-ray spectroscopy (EDX) spectra. Moreover, our results show mixed particles could be studied and identified based on the particle shape and elemental compn. using in situ SEM imaging and EDX. Thus, we provide a new and improved approach to observe the evolution of particle dispersion and stability in liq. under conditions similar to those in the waste tank. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs12gsL7J&md5=e15f260069fe826152bc1ac12e43ccee
- 119 Sekine, R. ; Moore, K. L. ; Matzke, M. ; Vallotton, P. ; Jiang, H. ; Hughes, G. M. ; Kirby, J. K. ; Donner, E. ; Grovenor, C. R. M. ; Svendsen, C. ; Lombi, E. Complementary Imaging of Silver Nanoparticle Interactions with Green Algae: Dark-Field Microscopy, Electron Microscopy, and Nanoscale Secondary Ion Mass Spectrometry . ACS Nano 2017 , 11 , 10894 – 10902 , DOI: 10.1021/acsnano.7b04556 119 Complementary Imaging of Silver Nanoparticle Interactions with Green Algae: Dark-Field Microscopy, Electron Microscopy, and Nanoscale Secondary Ion Mass Spectrometry Sekine, Ryo; Moore, Katie L.; Matzke, Marianne; Vallotton, Pascal; Jiang, Haibo; Hughes, Gareth M.; Kirby, Jason K.; Donner, Erica; Grovenor, Chris R. M.; Svendsen, Claus; Lombi, Enzo ACS Nano ( 2017 ), 11 ( 11 ), 10894-10902 CODEN: ANCAC3 ; ISSN: 1936-0851 . ( American Chemical Society ) Increasing consumer use of engineered nanomaterials has led to significantly increased efforts to understand their potential impact on the environment and living organisms. Currently, no individual technique can provide all the necessary information such as their size, distribution and chem. in complex biol. systems. Consequently, there is a need to develop complementary instrumental imaging approaches that provide enhanced understanding of these "bio-nano" interactions to overcome the limitations of individual techniques. Here we used a multimodal imaging approach incorporating dark-field light microscopy, high resoln. electron microscopy and nanoscale secondary ion mass spectrometry (NanoSIMS). The aim was to gain insight into the bio-nano interactions of surface functionalised silver nanoparticles (Ag-NPs) with the green algae Raphidocelis subcapitata, by combining the fidelity, spatial resoln., and elemental identification offered by the three techniques, resp. Each technique revealed that Ag-NPs interact with the green algae with a dependence on the size (10 nm vs. 60 nm) and surface functionality (tannic acid and branched polyethyleneimine, bPEI) of the NPs. Dark-field light microscopy revealed the presence of strong light-scatterers on the algal cell surface, and SEM imaging confirmed their nanoparticulate nature and localization at nanoscale resoln. NanoSIMS imaging confirmed their chem. identity as Ag, with the majority of signal concd. at the cell surface. Furthermore, SEM and NanoSIMS provided evidence of 10 nm bPEI Ag-NP internalization at higher concns. (40 μg/L), correlating with the highest toxicity obsd. from these NPs. This multimodal approach thus demonstrated an effective approach to complement dose-response studies in nano-(eco)-toxicol. investigations. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhslSit7rL&md5=4a4808e8ed35bcc4092f59da8cc9ba49
- 120 Guehrs, E. ; Schneider, M. ; Günther, C. M. ; Hessing, P. ; Heitz, K. ; Wittke, D. ; López-Serrano Oliver, A. ; Jakubowski, N. ; Plendl, J. ; Eisebitt, S. ; Haase, A. Quantification of Silver Nanoparticle Uptake and Distribution within Individual Human Macrophages by FIB/SEM Slice and View . J. Nanobiotechnol. 2017 , 15 , 1 – 11 , DOI: 10.1186/s12951-017-0255-8 There is no corresponding record for this reference.
- 121 Stabentheiner, E. ; Zankel, A. ; Pölt, P. Environmental Scanning Electron Microscopy (ESEM)─a Versatile Tool in Studying Plants . Protoplasma 2010 , 246 ( 1 ), 89 – 99 , DOI: 10.1007/s00709-010-0155-3 121 Environmental scanning electron microscopy (ESEM)--a versatile tool in studying plants Stabentheiner Edith; Zankel Armin; Polt Peter Protoplasma ( 2010 ), 246 ( 1-4 ), 89-99 ISSN: . Environmental scanning electron microscopy (ESEM) enables the investigation of hydrated and uncoated plant samples and the in situ observation of dynamic processes. Water vapor in the microscope chamber takes part in secondary electron detection and charge prevention. Two ESEM modes are available and offer a broad spectrum of applications. The environmental or wet mode prevents sample dehydration by the combination of sample cooling (5°C) and a vapor pressure of 4-6 Torr. In the low vacuum mode, the maximum chamber pressure is limited to 1 Torr (corresponding to about 5% relative humidity in the chamber) and allows the simultaneous use of a backscattered electron detector for imaging material contrast. A selection of characteristic plant samples and various applications are presented as a guide to ESEM for plant scientists. Leaf surfaces, trichomes, epicuticular waxes, and inorganic surface layers represent samples being comparatively resistant to dehydration, whereas callus cells and stigmatic tissue are examples for dehydration- and beam-sensitive samples. The potential of investigating dynamic processes in situ is demonstrated by studying anther opening, by tensile testing of leaves, and by performing hydration/dehydration experiments by changing the vapor pressure. Additionally, automated block-face imaging and serial sectioning using in situ ultramicrotomy is presented. The strengths and weaknesses of ESEM are discussed and it is shown that ESEM is a versatile tool in plant science. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3cflsVOksA%253D%253D&md5=bfa17a0249df8096107d333a837d6e6a
- 122 Agressott, E. V. H. ; Blätte, D. ; Cunha, F. A. ; Noronha, V. T. ; Ciesielski, R. ; Hartschuh, A. ; Paula, A. J. de ; Fechine, P. B. A. ; Souza Filho, A. G. ; Paschoal, A. R. Vibrational Spectroscopy and Morphological Studies on Protein-Capped Biosynthesized Silver Nanoparticles . ACS Omega 2020 , 5 , 386 – 393 , DOI: 10.1021/acsomega.9b02867 122 Vibrational Spectroscopy and Morphological Studies on Protein-Capped Biosynthesized Silver Nanoparticles Agressott, Enzo Victorino Hernandez; Blatte, Dominic; Cunha, Francisco Afranio; Noronha, Victor T.; Ciesielski, Richard; Hartschuh, Achim; de Paula, Amauri Jardim; Fechine, Pierre Basilio Almeida; Souza Filho, Antonio Gomes; Paschoal, Alexandre Rocha ACS Omega ( 2020 ), 5 ( 1 ), 386-393 CODEN: ACSODF ; ISSN: 2470-1343 . ( American Chemical Society ) Silver nanoparticles (AgNPs) have a large no. of applications in technol. and phys. and biol. sciences. These nanomaterials can be synthesized by chem. and biol. methods. The biol. synthesis using fungi represents a green approach for nanomaterial prodn. that has the advantage of biocompatibility. This work studies silver nanoparticles (AgNPs) produced by fungi Rhodotorula glutinis and Rhodotorula mucilaginosa found in ordinary soil of the Universidade Federal do Cear´a campus (Brazil). The biosynthesized AgNPs have a protein-capping layer involving a metallic Ag core. The focus of this paper is to investigate the size and structure of the capping layer, how it interacts with the Ag core, and how sensitive the system (core + protein) is to visible light illumination. For this, we employed SEM, AFM, photoluminescence spectroscopy, SERS, and dark-field spectroscopy. The AgNPs were isolated, and SEM measurements showed the av. size diam. between 58 nm for R. glutinis and 30 nm for R. mucilaginosa. These values are in agreement with the AFM measurements, which also provided the av. size diam. of 85 nm for R. glutinis and 56 nm for R. mucilaginosa as well as addnl. information about the av. size of the protein-capping layers, whose found values were 24 and 21 nm for R. mucilaginosa and R. glutinis nanoparticles, resp. The protein-capping layer structure seemed to be easily disturbed, and the SERS spectra were unstable. It was possible to identify Raman peaks that might be related to α-helix, β-sheet, and protein mixed structures. Finally, dark-field microscopy showed that the silver cores are very stable, but some are affected by the laser energy due to heating or melting. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsVCjsA%253D%253D&md5=611e45b2c8f2cfe57914563f3f794e2a
- 123 Williams, D. B. ; Carter, C. B. The Transmission Electron Microscope . In Transmission Electron Microscopy ; Springer US , 1996 ; pp 3 – 17 . There is no corresponding record for this reference.
- 124 Reymond-Laruinaz, S. ; Saviot, L. ; Potin, V. ; Marco de Lucas, M. C. Protein–Nanoparticle Interaction in Bioconjugated Silver Nanoparticles: A Transmission Electron Microscopy and Surface Enhanced Raman Spectroscopy Study . Appl. Surf. Sci. 2016 , 389 , 17 – 24 , DOI: 10.1016/j.apsusc.2016.07.082 124 Protein-nanoparticle interaction in bioconjugated silver nanoparticles: A transmission electron microscopy and surface enhanced Raman spectroscopy study Reymond-Laruinaz, Sebastien; Saviot, Lucien; Potin, Valerie; Marco de Lucas, Maria del Carmen Applied Surface Science ( 2016 ), 389 ( ), 17-24 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) Understanding the mechanisms of interaction between proteins and noble metal nanoparticles (NPs) is crucial to extend the use of NPs in biol. applications and nanomedicine. We report the synthesis of Ag-NPs:protein bioconjugates synthesized in total absence of citrates or other stabilizing agents in order to study the NP-protein interaction. Four common proteins (lysozyme, bovine serum albumin, cytochrome-C and Hb) were used in this work. Transmission electron microscopy (TEM) and surface enhanced Raman spectroscopy (SERS) were mainly used to study these bioconjugated NPs. TEM images showed Ag NPs with sizes in the 5-40 nm range. The presence of a protein layer surrounding the Ag NPs was also obsd. by TEM. Moreover, the compn. at different points of single bioconjugated NPs was probed by electron energy loss spectroscopy (EELS). The thickness of the protein layer varies in the 3-15 nm range and the Ag NPs are a few nanometers away. This allowed to obtain an enhancement of the Raman signal of the proteins in the anal. of water suspensions of bioconjugates. SERS results showed a broadening of the Raman bands of the proteins which we attribute to the contribution of different configurations of the proteins adsorbed on the Ag NPs surface. Moreover, the assignment of an intense and sharp peak in the low-frequency range to Ag-N vibrations points to the chemisorption of the proteins on the Ag-NPs surface. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFyms77F&md5=24076cfb18cdd0a485e6159151a0befb
- 125 Qin, D. ; Yang, G. ; Wang, Y. ; Zhou, Y. ; Zhang, L. Green Synthesis of Biocompatible Trypsin-Conjugated Ag Nanocomposite with Antibacterial Activity . Appl. Surf. Sci. 2019 , 469 , 528 – 536 , DOI: 10.1016/j.apsusc.2018.11.057 125 Green synthesis of biocompatible trypsin-conjugated Ag nanocomposite with antibacterial activity Qin, Dezhi; Yang, Guangrui; Wang, Yabo; Zhou, Yanbiao; Zhang, Li Applied Surface Science ( 2019 ), 469 ( ), 528-536 CODEN: ASUSEE ; ISSN: 0169-4332 . ( Elsevier B.V. ) In this work, water-sol. Ag nanoparticles were prepd. in aq. soln. by using trypsin as reducing and capping agent. The protein-assisted synthetic strategy eliminates the need of intermediate protecting and linking agents compared with organometallic approach, which is simple, effect, less energy consuming, and closer to the requirements of green chem. The morphol., size and antibacterial activity properties could be controlled by varying exptl. conditions. The results of FT-IR and SDS-PAGE anal. indicated that trypsin mols. could control the nucleation and growth of nanocrystals through chem. interaction between Ag and functional groups of trypsin. The binding of trypsin on the surface of Ag nanoparticles significantly reduced nano-toxicity through capping effect. The trypsin-conjugated Ag nanoparticles exhibited strong antibacterial activity toward both Gram-pos. and Gram-neg. bacteria due to small size and specific morphologies. Compared with traditional antibacterial materials, the water-soly. and biocompatibility make the products more suitable for the application in biol. and medical science. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1eisLzK&md5=2f0e6ad63a7430d4bbd4f9a957088777
- 126 Min, Y. ; Akbulut, M. ; Kristiansen, K. ; Golan, Y. ; Israelachvili, J. The Role of Interparticle and External Forces in Nanoparticle Assembly . Nat. Mater. 2008 , 7 , 527 – 538 , DOI: 10.1038/nmat2206 126 The role of interparticle and external forces in nanoparticle assembly Min, Younjin; Akbulut, Mustafa; Kristiansen, Kai; Golan, Yuval; Israelachvili, Jacob Nature Materials ( 2008 ), 7 ( 7 ), 527-538 CODEN: NMAACR ; ISSN: 1476-1122 . ( Nature Publishing Group ) A review. The past 20 years have witnessed simultaneous multidisciplinary explosions in exptl. techniques for synthesizing new materials, measuring and manipulating nanoscale structures, understanding biol. processes at the nanoscale, and carrying out large-scale computations of many-atom and complex macromol. systems. These advances have led to the new disciplines of nanoscience and nanoengineering. For reasons that are discussed here, most nanoparticles do not 'self-assemble' into their thermodynamically lowest energy state, and require an input of energy or external forces to 'direct' them into particular structures or assemblies. We discuss why and how a combination of self- and directed-assembly processes, involving interparticle and externally applied forces, can be applied to produce desired nanostructured materials. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXnslKqsrc%253D&md5=53d6916315dccf43b9d72be033f6453a
- 127 Velegol, D. Assembling Colloidal Devices by Controlling Interparticle Forces . J. Nanophotonics 2007 , 1 , 012502 , DOI: 10.1117/1.2759184 There is no corresponding record for this reference.
- 128 Nel, A. ; Xia, T. ; Mädler, L. ; Li, N. Toxic Potential of Materials at the Nanolevel . Science 2006 , 311 , 622 – 627 , DOI: 10.1126/science.1114397 128 Toxic Potential of Materials at the Nanolevel Nel, Andre; Xia, Tian; Maedler, Lutz; Li, Ning Science (Washington, DC, United States) ( 2006 ), 311 ( 5761 ), 622-627 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) A review. Nanomaterials are engineered structures with at least one dimension of 100 nm or less. These materials are increasingly being used for com. purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and drug carriers. Materials in this size range may approach the length scale at which some specific phys. or chem. interactions with their environment can occur. As a result, their properties differ substantially from those bulk materials of the same compn., allowing them to perform exceptional feats of cond., reactivity, and optical sensitivity. Possible undesirable results of these capabilities are harmful interactions with biol. systems and the environment, with the potential to generate toxicity. The establishment of principles and test procedures to ensure safe manuf. and use of nanomaterials in the marketplace is urgently required and achievable. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XptVyrsg%253D%253D&md5=584e4f8683594cff5ed7bcd039b7cdf3
- 129 Dagastine, R. R. ; Manica, R. ; Carnie, S. L. ; Chan, D. Y. C. ; Stevens, G. W. ; Grieser, F. Dynamic Forces between Two Deformable Oil Droplets in Water . Science 2006 , 313 , 210 – 213 , DOI: 10.1126/science.1125527 129 Dynamic Forces Between Two Deformable Oil Droplets in Water Dagastine, Raymond R.; Manica, Rogerio; Carnie, Steven L.; Chan, D. Y. C.; Stevens, Geoffrey W.; Grieser, Franz Science (Washington, DC, United States) ( 2006 ), 313 ( 5784 ), 210-213 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) The understanding of static interactions in colloidal suspensions is well established, whereas dynamic interactions more relevant to biol. and other suspended soft-matter systems are less well understood. We present the direct force measurement and quant. theor. description for dynamic forces for liq. droplets in another immiscible fluid. Anal. of this system demonstrates the strong link between interfacial deformation, static surface forces, and hydrodynamic drainage, which govern dynamic droplet-droplet interactions over the length scale of nanometers and over the time scales of Brownian collisions. The results and anal. have direct bearing on the control and manipulation of suspended droplets in soft-matter systems ranging from the emulsions in shampoo to cellular interactions. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xmslagu7s%253D&md5=bebc6cc5c21a65e8d934339ac47dc5eb
- 130 Kim, H. Y. ; Sofo, J. O. ; Velegol, D. ; Cole, M. W. ; Lucas, A. A. Van Der Waals Dispersion Forces between Dielectric Nanoclusters . Langmuir 2007 , 23 , 1735 – 1740 , DOI: 10.1021/la061802w 130 Van der Waals Dispersion Forces between Dielectric Nanoclusters Kim, Hye-Young; Sofo, Jorge O.; Velegol, Darrell; Cole, Milton W.; Lucas, Amand A. Langmuir ( 2007 ), 23 ( 4 ), 1735-1740 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Various methods are evaluated for their ability to calc. accurate van der Waals (VDW) dispersion forces between nanoclusters. We compare results for spheres using several methods: the simple Hamaker two-body method, the Lifshitz (DLP) theory with the Derjaguin approxn., the Langbein result for spheres, and our "coupled dipole method" (CDM). The assumptions and shortcomings of each method are discussed. The CDM accounts for all n-body forces, does not assume a continuous and homogeneous dielec. function in each material, accounts for the discreteness of atoms in the particles, can be used for particles of arbitrary shape, and can exactly include the effects of various media. At present, the CDM does not account for retardation. Even for spheres, methods other than the CDM often give errors of 20% or more for VDW dispersion forces between typical dielec. materials. A related calcn. for metals reveals an error in the Hamaker two-body result of nearly a factor of 2. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlektLvE&md5=dcaf19b0de6e014dab68be8d5bf691f6
- 131 Word, J. M. ; Lovell, S. C. ; Richardson, J. S. ; Richardson, D. C. Asparagine and Glutamine: Using Hydrogen Atom Contacts in the Choice of Side-Chain Amide Orientation . J. Mol. Bio. 1999 , 285 , 1735 – 1747 , DOI: 10.1006/jmbi.1998.2401 131 Asparagine and Glutamine: Using Hydrogen Atom Contacts in the Choice of Side-chain Amide Orientation Word, J. Michael; Lovell, Simon C.; Richardson, Jane S.; Richardson, David C. Journal of Molecular Biology ( 1999 ), 285 ( 4 ), 1735-1747 CODEN: JMOBAK ; ISSN: 0022-2836 . ( Academic Press ) Small-probe contact dot surface anal., with all explicit hydrogen atoms added and their van der Waals contacts included, was used to choose between the two possible orientations for each of 1554 asparagine (Asn) and glutamine (Gln) side-chain amide groups in a dataset of 100 unrelated, high-quality protein crystal structures at 0.9 to 1.7 Å resoln. For the movable-H groups, each connected, closed set of local H-bonds was optimized for both H-bonds and van der Waals overlaps. In addn. to the Asn/Gln "flips", this process included rotation of OH, SH, NH3+, and methionine Me H atoms, flip and protonation state of histidine rings, interaction with bound ligands, and a simple model of water interactions. However, except for switching N and O identity for amide flips (or N and C identity for His flips), no non-H atoms were shifted. Even in these very high-quality structures, about 20 % of the Asn/Gln side-chains required a 180° flip to optimize H-bonding and/or to avoid NH2 clashes with neighboring atoms (incorporating a conservative score penalty which, for marginal cases, favors the assignment in the original coordinate file). The programs Reduce, Probe, and Mage provide not only a suggested amide orientation, but also a numerical score comparison, a categorization of the marginal cases, and a direct visualization of all relevant interactions in both orientations. Visual examn. allowed confirmation of the raw score assignment for about 40 % of those Asn/Gln flips placed within the "marginal" penalty range by the automated algorithm, while uncovering only a small no. of cases whose automated assignment was incorrect because of special circumstances not yet handled by the algorithm. It seems that the H-bond and the at.-clash criteria independently look at the same structural realities: when both criteria gave a clear answer, they agreed every time. But consideration of van der Waals clashes settled many addnl. cases for which H-bonding was either absent or approx. equiv. for the two main alternatives. With this extra information, 86 % of all side-chain amide groups could be oriented quite unambiguously. In the absence of further exptl. data, it would probably be inappropriate to assign many more than this. Some of the remaining 14 % are ambiguous because of coordinate error or inadequacy of the theor. model, but the great majority of ambiguous cases probably occur as a dynamic mix of both flip states in the actual protein mol. The software and the 100 coordinate files with all H atoms added and optimized and with amide flips cor. are publicly available. (c) 1999 Academic Press. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXhtV2ht7g%253D&md5=a3bd044a8652a5ac03e2eb7b9414c2e0
- 132 Arai, T. ; Norde, W. The Behavior of Some Model Proteins at Solid-Liquid Interfaces 1. Adsorption from Single Protein Solutions . Colloids Surf. 1990 , 51 ( C ), 1 – 15 , DOI: 10.1016/0166-6622(90)80127-P 132 The behavior of some model proteins at solid-liquid interfaces. 1. Adsorption from single protein solutions Arai, Takaaki; Norde, Willem Colloids and Surfaces ( 1990 ), 51 ( ), 1-15 CODEN: COSUD3 ; ISSN: 0166-6622 . The adsorption of proteins of similar mol. size and shape on various well-defined surfaces is discussed. The hydrophobicity and the elec. charge d. of both the protein mol. and the sorbent surface as well as the structure stability of the protein mol. were taken as the exptl. variables. The adsorption process was studied by detg. adsorption isotherms and by measuring electrophoretic mobilities and heats of adsorption at varying degrees of coverage of the sorbent surface by the protein. It appeared that proteins of which the structure is stabilized by a large Gibbs energy behave like hard particles: they adsorb on hydrophobic interfaces under all conditions of charge interaction and on hydrophilic surfaces only if electrostatically attracted. Soft proteins, i.e., proteins characterized by a lower structure stability, adsorb on hydrophobic and hydrophilic surfaces under attractive and repulsive electrostatic conditions. These proteins contain an extra driving force for adsorption, related to structure rearrangements in the mol., that outweighs the unfavorable contributions form hydrophilic dehydration and electrostatic repulsion. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXmvFOnuw%253D%253D&md5=0be38d305742fa4a562fc51edff91bee
- 133 Norde, W. ; Giacomelli, C. E. BSA Structural Changes during Homomolecular Exchange between the Adsorbed and the Dissolved States . J. Biotechnol. 2000 , 79 ( 3 ), 259 – 268 , DOI: 10.1016/S0168-1656(00)00242-X 133 BSA structural changes during homomolecular exchange between the adsorbed and the dissolved states Norde, W.; Giacomelli, C. E. Journal of Biotechnology ( 2000 ), 79 ( 3 ), 259-268 CODEN: JBITD4 ; ISSN: 0168-1656 . ( Elsevier Science Ltd. ) The secondary structure and the thermostability of bovine serum albumin (BSA), before adsorption and after homomol. displacement from silica and polystyrene particles, are studied by CD spectroscopy and differential scanning calorimetry. The structural perturbations induced by the hydrophilic silica surface are reversible, i.e. BSA completely regains the native structure and stability after being exchanged. On the other hand, the adsorption on, and subsequent desorption from, polystyrene particles causes irreversible changes in the stability and (secondary) structure of BSA. The exchanged proteins have a higher denaturation temp. and a lower enthalpy of denaturation than native BSA. The α-helix content is reduced while the β-turn fraction is increased in the exchanged mols. Both effects are more pronounced when the protein is displaced from less crowded sorbent surfaces. The irreversible surface-induced conformational change may be related to some aggregation of BSA mols. after being exposed to a hydrophobic surface. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXktV2rtrs%253D&md5=eab9e55e71de8cb4901562775bb82969
- 134 Aubin-Tam, M. E. ; Hamad-Schifferli, K. Gold Nanoparticle-Cytochrome c Complexes: The Effect of Nanoparticle Ligand Charge on Protein Structure . Langmuir 2005 , 21 , 12080 – 12084 , DOI: 10.1021/la052102e 134 Gold Nanoparticle-Cytochrome c Complexes: The Effect of Nanoparticle Ligand Charge on Protein Structure Aubin-Tam, Marie-Eve; Hamad-Schifferli, Kimberly Langmuir ( 2005 ), 21 ( 26 ), 12080-12084 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) We report the effect of nanoparticle ligand charge on the structure of a covalently, site-specifically linked protein. Au nanoparticles with pos., neg., and neutral ligands were appended to a specific cysteine, C102, of Saccharomyces cerevisiae cytochrome c. Conjugates were purified by HPLC or gel electrophoresis. CD spectroscopy shows that changing the nanoparticle ligand dramatically influences the attached cytochrome c structure. The protein retains its structure with neutral ligands but denatures in the presence of charged species. This is rationalized by the electrostatic interaction of amino acids in the local vicinity of C102 with the endgroups of the ligand. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1SgtrfI&md5=75d480b3eb03450e07dd8bee2cf0db56
- 135 Jalab, J. ; Abdelwahed, W. ; Kitaz, A. ; Al-Kayali, R. Green Synthesis of Silver Nanoparticles Using Aqueous Extract of Acacia Cyanophylla and Its Antibacterial Activity . Heliyon 2021 , 7 , e08033 DOI: 10.1016/j.heliyon.2021.e08033 There is no corresponding record for this reference.
- 136 Ghanbar, F. ; Mirzaie, A. ; Ashrafi, F. ; Noorbazargan, H. ; Dalirsaber Jalali, M. ; Salehi, S. ; Sadat Shandiz, S. A. Antioxidant, Antibacterial and Anticancer Properties of Phyto-Synthesised Artemisia Quttensis Podlech Extract Mediated AgNPs . IET Nanobiotechnol 2017 , 11 ( 4 ), 485 – 492 , DOI: 10.1049/iet-nbt.2016.0101 136 Antioxidant, antibacterial and anticancer properties of phyto-synthesised Artemisia quttensis Podlech extract mediated AgNPs Ghanbar Farinaz; Ashrafi Fatemeh; Mirzaie Amir; Sadat Shandiz Seyed Ataollah; Noorbazargan Hassan; Dalirsaber Jalali Mojgan; Salehi Soheil IET nanobiotechnology ( 2017 ), 11 ( 4 ), 485-492 ISSN: 1751-8741 . The focus of this study is on a rapid and cost-effective approach for the synthesis of silver nanoparticles (AgNPs) using Artemisia quttensis Podlech aerial parts extract and assessment of their antioxidant, antibacterial and anticancer activities. The prepared AgNPs were determined by ultraviolet-visible spectroscopy, X-ray diffraction, Fourier transform infra-red spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and dynamic light scattering and zeta-potential analysis. The AgNPs and A. quttensis extract were evaluated for their antiradical scavenging activity by 2, 2-diphenyl, 1-picryl hydrazyl assay and anticancer activity against colon cancer (human colorectal adenocarcinoma cell line 29) compared with normal human embryonic kidney (HEK293) cells. Also, the prepared AgNPs were studied for its antibacterial activity. The AgNPs revealed a higher antioxidant activity compared with A. quttensis extract alone. The phyto-synthesised AgNPs and A. quttensis extract showed a dose-response cytotoxicity effect against HT29 and HEK293 cells. As evidenced by Annexin V/propidium iodide staining, the number of apoptotic HT29 cells was significantly enhanced, following treatment with AgNPs as compared with untreated cells. Besides, the antibacterial property of the AgNPs indicated a significant effect against the selected pathogenic bacteria. These present obtained results show the potential applications of phyto-synthesised AgNPs using A. quttensis aerial parts extract. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1crpvVKlug%253D%253D&md5=c1a01e27839657fc35cb452084fc58af
- 137 Emam, M. ; el Raey, M. A. ; Eisa, W. H. ; El- Haddad, A. E. ; Osman, S. M. ; El-Ansari, M. A. ; Rabie, A. G. M. Green Synthesis of Silver Nanoparticles from Caesalpinia Gilliesii (Hook) Leaves: Antimicrobial Activity and in Vitro Cytotoxic Effect against BJ-1 and MCF-7 Cells . J. Appl. Pharm. Sci. 2017 , 7 , 226 – 233 , DOI: 10.7324/JAPS.2017.70831 137 Green synthesis of silver nanoparticles from Caesalpinia gilliesii (Hook) leaves: antimicrobial activity and in vitro cytotoxic effect against BJ-1 and MCF-7 cells Emam, Mahmoud; el Raey, Mohamed A.; Eisa, Wael H.; El-Haddad, Alaadin E.; Osman, Samir M.; El-Ansari, Mohamed A.; Rabie, Abdel-Gawad M. Journal of Applied Pharmaceutical Science ( 2017 ), 7 ( 8 ), 226-233 CODEN: JAPSHX ; ISSN: 2231-3354 . ( Journal of Applied Pharmaceutical Science ) Green synthesis of silver nanoparticles using Caesalpinia gilliesii (Hook) leaves ext. (70% MeOH) for the first time as a reducing agent were investigated for their antimicrobial and cytotoxic activity (using the MTT assay). After exposing the oxidizing agent of silver ions to C. gilliesii leaves ext., the rapid redn. in the soln. is obsd. due to the construction of silver nanoparticles. The prepd. nanoparticles were elucidated by using UV-visible spectroscopy, Fourier Transforms IR spectroscopy (FT-IR) and transmission electron microscope (TEM). The purified silver nanoparticles demonstrated promising antimicrobial activity against tested pathogens than hydroalcoholic ext. Cell viability by using the MTT assay demonstrated cytotoxic activity of the synthesized Ag NPs with C. gilliesii against normal skin fibroblast (BJ-1) and human breast cancer cell (MCF-7) with IC50= 80.1 and 36.5 μg/mL at 48 h incubation, resp. Depending on the phenolic and flavonoid contents, C. gilliesii could be used for simple, nonhazardous, eco-friendly, cost-effective and efficient synthesis of Ag NPs that can be applied into medicinal field. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisVOrtLzO&md5=28377dce2fd51180b6a859bc2fe2dd7e
- 138 Geetha, N. ; Geetha, T. S. ; Manonmani, P. ; Thiyagarajan, M. Green Synthesis of Silver Nanoparticles Using Cymbopogan Citratus (Dc) Stapf. Extract and Its Antibacterial Activity . Aust.J.Basic Appl. Sci. 2014 , 8 , 324 – 331 , DOI: 10.7324/JAPS.2017.70831 138 Green synthesis of silver nanoparticles using Cymbopogan citratus (Dc) Stapf. extract and its antibacterial activity Geetha, Natesan; Geetha, Thangarajan Sarojini; Manonmani, Pandiyan; Thiyagarajan, M. Australian Journal of Basic and Applied Sciences ( 2014 ), 8 ( 3 ), 324-331, 8 CODEN: AJBAB3 ; ISSN: 1991-8178 . ( AENSI Publications ) Background: There is an increasing com. demand for nanoparticles due to their wide applicability in different fields such as catalysis, photonics, electronics, biol. labeling, biosensing, drug delivery, antibacterial, and antiviral and gene therapy. Physicochem. methods of nanoparticle synthesis causes environment hazards, so biol. approach has emerged as eco-friendly and alternative method. Cymbopogan citratus (DC) stapf. is commonly known as lemon grass belongs to a family Poaceae. It is a native arom. herb from India and is also cultivated in other tropical and subtropical countries. Objective: The main objective of the study is synthesis and characterization of silver nanoparticles in lemon grass leaves and to study its antibacterial activity. Results: The silver nanoparticles were formed after 3 h of incubation at 37°C using aq. soln. of 5 mM silver nitrate (AgNO3) and synthesized silver nanoparticles were characterized by UV-vis, XRD, SEM,EDS and FTIR. The antibacterial activity of synthesized silver nanoparticles was investigated by disk diffusion method. Conclusion: In the present study silver nanoparticles was synthesized by green route and significant antibacterial activity was also obsd. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtleqsL%252FI&md5=e86406fbd3f51a690d21cd3c11fcc634
- 139 Singh, H. ; Du, J. ; Singh, P. ; Yi, T. H. Ecofriendly Synthesis of Silver and Gold Nanoparticles by Euphrasia Officinalis Leaf Extract and Its Biomedical Applications . Artif. Cells, Nanomed., Biotechnol. 2018 , 46 ( 6 ), 1163 – 1170 , DOI: 10.1080/21691401.2017.1362417 139 Ecofriendly synthesis of silver and gold nanoparticles by Euphrasia officinalis leaf extract and its biomedical applications Singh, Hina; Du, Juan; Singh, Priyanka; Yi, Tae Hoo Artificial Cells, Nanomedicine, and Biotechnology ( 2018 ), 46 ( 6 ), 1163-1170 CODEN: ACNBCI ; ISSN: 2169-141X . ( Taylor & Francis Ltd. ) Biogenic synthesis of silver (AgNPs) and gold nanoparticles (AuNPs) using aq. ext. of Euphrasia officinalis has been reported. Stable AgNPs and AuNPs were formed on adding aq. solns. of silver nitrate and chloroauric acid with E. officinalis leaf ext., in 19 min and 2 min, resp. The synthesis method used in present study was simple, reliable, rapid, cost effective and ecofriendly. The synthesized nanoparticles were characterized with field emission transmission electron microscopy (FE-TEM), elemental mapping, selected area diffraction pattern (SAED), energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform IR spectroscopy (FTIR). The UV-Vis spectrum confirmed the synthesis of nanoparticles as the absorption band was obsd. at 450 nm for AgNPs and at 558 nm for AuNPs. The TEM images revealed quasi-spherical shape of AgNPs and AuNPs. The size of nanoparticles was detd. to be 40.37 ± 1.8 nm for AgNPs and 49.72 ± 1.2 nm for AuNPs. The zeta potential value demonstrated the neg. surface charge and stable nature of nanoparticles. Cryst. nature of the nanoparticles in the face-centered cubic (fcc) structure was confirmed by the peaks in the XRD pattern and SAED pattern. FTIR results showed the functional groups involved in redn. of silver and gold ions to metal nanoparticles. For biomedical application, the nanoparticles have been explored for anticancer, antibacterial and biofilm inhibition activities. It was obsd. that AgNPs exert anticancer activity against human lung cancer (A549) and human cervical cancer (HeLa) cell lines. On the other hand, AuNPs were able to inhibit only human cervical cancer cells. Furthermore, the AgNPs were active against clin. isolated human pathogens like Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Vibrio parahaemolyticus. Addnl., AgNPs also showed biofilm inhibition activity against S. aureus and P. aeruginosa. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXht12lt7bP&md5=0fcb4f5714bc67f6f4e19556dcbb1a2f
- 140 Suchithra, M. R. ; Bhuvaneswari, S. ; Sampathkumar, P. ; Dineshkumar, R. ; Chithradevi, K. ; Beevi farhana noor, M. ; Madhumitha, R. ; Kavisri, M. In Vitro Study of Antioxidant, Antidiabetic and Antiurolithiatic Activity of Synthesized Silver Nanoparticles Using Stem Bark Extracts of Hybanthus Enneaspermus . Biocatal. Agric. Biotechnol. 2021 , 38 , 102219 , DOI: 10.1016/j.bcab.2021.102219 140 In vitro study of antioxidant, antidiabetic and antiurolithiatic activity of synthesized silver nanoparticles using stem bark extracts of Hybanthus enneaspermus Suchithra, M. R.; Bhuvaneswari, S.; Sampathkumar, P.; Dineshkumar, R.; Chithradevi, K.; Beevi farhana noor, M.; Madhumitha, R.; Kavisri, M. Biocatalysis and Agricultural Biotechnology ( 2021 ), 38 ( ), 102219 CODEN: BABICA ; ISSN: 1878-8181 . ( Elsevier Ltd. ) Diabetes mellitus is an endocrine disorder that affects 85% of the people because of higher sugar level in blood. Due to this metabolic disorder and improper function of organs esp. kidney results in urinary tract infection causing struvite urinary stone. So, in the present study was carried out to study the green synthesized silver nanoparticles using Hybanthus enneaspermus stem bark exts. on antioxidant, antidiabetic and antiurolithiatic activity under in vitro conditions. By the treatment of aq. soln. of 5 mM silver nitrate (AgNO3) with stem bark exts., silver nanoparticles could be quickly synthesized within 1 h. These silver nanoparticles were characterized using UV-Visible spectroscopy, Fourier Transform IR Spectroscopy (FT-IR), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and Dynamic Light Scattering (DLS) for further confirmation. TEM anal. found that the silver nanoparticles are spherical in shape. X-ray diffraction confirmed that silver nanostructure exhibit a fcc. crystal structure. DLS showed that the nanoparticles size is 644.2 nm. By increasing the concn. of silver nanoparticles, wt. of the formed crystals reduced from 0.94 g to 0.13 g in struvite crystals and analyzed by FTIR analyses. This multidisciplinary approach showed a better percentage of inhibition such as antioxidant, antidiabetic and antiurolithiatic activity of silver nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XmvVKkurg%253D&md5=cca6aeec751dbd5326a8c618076575c3
- 141 Schön, G. ; Simon, U. A Fascinating New Field in Colloid Science: Small Ligand-Stabilized Metal Clusters and Their Possible Application in Microelectronics - Part II: Future Directions . Colloid Polym. Sci. 1995 , 273 , 202 – 218 , DOI: 10.1007/BF00657826 There is no corresponding record for this reference.
- 142 Brus, L. Electronic Wave Functions in Semiconductor Clusters: Experiment and Theory . J. Phys. Chem. 1986 , 90 , 2555 – 2560 , DOI: 10.1021/j100403a003 142 Electronic wave functions in semiconductor clusters: experiment and theory Brus, Louis Journal of Physical Chemistry ( 1986 ), 90 ( 12 ), 2555-60 CODEN: JPCHAX ; ISSN: 0022-3654 . Recent exptl. and theor. work in the size-dependent development of bulk electronic properties in semiconductor crystallites of ∼15 to several hundred are critically reviewed and discussed. Semiconducting electronic properties are explained in chem. valence terminol. These crystallites can be termed "clusters" because they are too small to have bulblike electronic wave functions even though they exhibit bulklike crystal structure. The principal exptl. evidence comes from the recent discovery that liq.-phase pptn. reactions can be controlled to make and stabilize cryst. semiconductor clusters in this size range. The cluster electronic properties can be studied optically in dil. colloidal solns. The cluster internal crystal structure is directly revealed by transmission electron microscopy. The results indicate that the approach of cluster electronic wave functions to the bulk Bloch MOs is exceedingly slow as a function of cluster size. This result can be anal. predicted in terms of the intrinsic electron delocalization present in cryst. materials with strong, directional chem. bonding. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XktFagtr0%253D&md5=480cab9cd92fd4d95d8be577a9bf7e0a
- 143 Wang, Y. ; Herron, N. Nanometer-Sized Semiconductor Clusters: Materials Synthesis, Quantum Size Effects, and Photophysical Properties . J. Phys. Chem. 1991 , 95 , 525 – 532 , DOI: 10.1021/j100155a009 143 Nanometer-sized semiconductor clusters: materials synthesis, quantum size effects, and photophysical properties Wang, Ying; Herron, N. Journal of Physical Chemistry ( 1991 ), 95 ( 2 ), 525-32 CODEN: JPCHAX ; ISSN: 0022-3654 . A review with 67 refs. Recent advances in the synthesis of semiconductor clusters open a doorway for the systematic study of size-dependent cluster properties in the condensed phase. The size effect on the optical and photophys. properties are discussed. Fundamental concepts are discussed and a discussion is given of recent progress toward the understanding of the quantum size effect and dielec. confinement effect. The current status is discussed of materials synthesis and the prospect for making monodisperse clusters of well-defined surfaces. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXntFWqsw%253D%253D&md5=88fdf459b82252eaf95ab153f495eb6a
- 144 Chen, D. H. ; Chen, Y. Y. Synthesis of Strontium Ferrite Nanoparticles by Coprecipitation in the Presence of Polyacrylic Acid . Mater. Res. Bull. 2002 , 37 , 801 – 810 , DOI: 10.1016/S0025-5408(01)00590-6 144 Synthesis of strontium ferrite nanoparticles by coprecipitation in the presence of polyacrylic acid Chen, Dong-Hwang; Chen, Yuh-Yuh Materials Research Bulletin ( 2002 ), 37 ( 4 ), 801-810 CODEN: MRBUAC ; ISSN: 0025-5408 . ( Elsevier Science Inc. ) Sr ferrite (SrFe12O19) nanoparticles were prepd. by copptn. in a PAA aq. soln. The av. diam. of the mixed hydroxide ppts. was 3.1 nm. From the thermal anal. by TGA/DTA and the phase anal. by XRD, the appropriate molar ratio of Sr/Fe in aq. soln. was 1/8 and the precursor could yield pure Sr ferrite after calcination at >700°. The av. diams. of the Sr ferrite nanoparticles calcined at 700 and 800° were 34 and 41 nm, resp. The magnetic measurements indicated that their satn. magnetization (57-59 emu/g) reached 85-88% of the theor. one and increased with the decrease of temp. at 5-400 K Their coercivity values (55-67 Oe) were much lower than those reported earlier, revealing the resultant nanoparticles were superparamagnetic. All the magnetic properties obsd. reflected the nature of nanoparticles and also concerned with their morphol. and microstructure. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xis1eiuro%253D&md5=1d458335f0ea2f435e88d47317e092db
- 145 Sharma, R. K. ; Sharma, P. ; Maitra, A. Size-Dependent Catalytic Behavior of Platinum Nanoparticles on the Hexacyanoferrate(III)/Thiosulfate Redox Reaction . J. Colloid Interface Sci. 2003 , 265 , 134 – 140 , DOI: 10.1016/S0021-9797(03)00463-6 145 Size-dependent catalytic behavior of platinum nanoparticles on the hexacyanoferrate(III)/thiosulfate redox reaction Sharma, Rakesh Kumar; Sharma, Parvesh; Maitra, Amarnath Journal of Colloid and Interface Science ( 2003 ), 265 ( 1 ), 134-140 CODEN: JCISA5 ; ISSN: 0021-9797 . ( Elsevier Science ) Pt nanoparticles prepd. in reverse micelles were used as catalysts for the electron transfer reaction between hexacyanoferrate(III) and thiosulfate ions. Nanoparticles of av. diam. ranging between 10 and 80 nm were used as catalysts. The kinetic study of the catalytic reaction showed that for a fixed mass of catalyst the catalytic rate did not increase proportionately to the decrease in particle size over the whole range from 10 to 80 nm. The max. reaction rate was obsd. for av. particle diam. of ∼38 nm. Particles below diam. 38 nm exhibit a trend of decreasing reaction rate with the decrease in particle size, while those above diam. 38 nm show a steady decline of reaction rate with increasing size. It was postulated that in the case of particles of av. size <38 nm diam., a downward shift of Fermi level with a consequent increase of band gap energy takes place. As a result, the particles require more energy to pump electrons to the adsorbed ions for the electron transfer reaction. This leads to a reduced reaction rate catalyzed by smaller particles. However, for nanoparticles above diam. 38 nm, the change of Fermi level is not appreciable. These particles exhibit less surface area for adsorption as the particle size is increased. As a result, the catalytic efficiency of the particles is also decreased with increased particle size. The activation energies for the reaction catalyzed by Pt nanoparticles of diams. 12 and 30 nm are ∼18 and 4.8 kJ/mol, resp., indicating that the catalytic efficiency of 12-nm-diam. Pt particles is less than that of particles of diam. 30 nm. Extremely slow reaction rate of uncatalyzed reaction was manifested through a larger activation energy of ∼40 kJ/mol for the reaction. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmtFansrc%253D&md5=1c3b27d76823f90a38fb28cb8a40c71a
- 146 Gao, J. ; Fu, J. ; Lin, C. ; Lin, J. ; Han, Y. ; Yu, X. ; Pan, C. Formation and Photoluminescence of Silver Nanoparticles Stabilized by a Two-Armed Polymer with a Crown Ether Core . Langmuir 2004 , 20 , 9775 – 9779 , DOI: 10.1021/la049197p 146 Formation and Photoluminescence of Silver Nanoparticles Stabilized by a Two-Armed Polymer with a Crown Ether Core Gao, Junpeng; Fu, Jun; Lin, Cuikun; Lin, Jun; Han, Yanchun; Yu, Xiang; Pan, Caiyuan Langmuir ( 2004 ), 20 ( 22 ), 9775-9779 CODEN: LANGD5 ; ISSN: 0743-7463 . ( American Chemical Society ) Ag nanoparticles were synthesized using a two-armed polymer with a crown ether core [poly(styrene)]-dibenzo-18-crown-6-[poly(styrene)] based on the flexibility of the polymer chains and the complex effect of crown ether with Ag+ and Ag. The size of Ag nanoparticles could be tailored by controlling the initial concns. of the polymer and Ag+, and the mol. wt. of the polymer. The emission of Ag nanoparticles was blue-shifted, and the intensity of the photoluminescence of Ag nanoparticles stabilized by the polymer was significantly increased due to the complex effect between the crown ether embedded in the polymer and the Ag nanoparticles. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnvFGns78%253D&md5=bec9fd10e51f49105758d73081eaa161
- 147 Kuo, P. L. ; Chen, W. F. Formation of Silver Nanoparticles under Structured Amino Groups in Pseudo-Dendritic Poly(Allylamine) Derivatives . J. Phys. Chem. B 2003 , 107 , 11267 – 11272 , DOI: 10.1021/jp030116s 147 Formation of Silver Nanoparticles under Structured Amino Groups in Pseudo-dendritic Poly(allylamine) Derivatives Kuo, Ping-Lin; Chen, Wei-Fu Journal of Physical Chemistry B ( 2003 ), 107 ( 41 ), 11267-11272 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) The syntheses of silver nanoparticles stabilized by poly(allylamine) (PAA) and by polyethyleneiminated poly(allylamine) (PAA(EI)n (n = 2, 5.8)) are reported. The architectural effects in particle on the nanoparticle size, size distribution, and agglomeration behavior are detd. from the UV-vis plasmon absorption band and transmission electron microscopic (TEM) analyses. The data show that PAA(EI)n display better stabilizing effects than PAA to prevent silver particles from agglomeration. Different phenomena of the polymer-protected nanoparticles at various silver ion concns. are obsd. and are explained in terms of a mechanism of structure-dependent stabilization. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnsVOjs7c%253D&md5=a3058a27f3f78a79f5c2153989a2c326
- 148 Yan, W. ; Chen, B. ; Mahurin, S. M. ; Schwartz, V. ; Mullins, D. R. ; Lupini, A. R. ; Pennycook, S. J. ; Dai, S. ; Overbury, S. H. Preparation and Comparison of Supported Gold Nanocatalysts on Anatase, Brookite, Rutile, and P25 Polymorphs of TiO 2 for Catalytic Oxidation of CO . J. Phys. Chem. B 2005 , 109 , 10676 – 10685 , DOI: 10.1021/jp044091o 148 Preparation and Comparison of Supported Gold Nanocatalysts on Anatase, Brookite, Rutile, and P25 Polymorphs of TiO2 for Catalytic Oxidation of CO Yan, Wenfu; Chen, Bei; Mahurin, S. M.; Schwartz, V.; Mullins, D. R.; Lupini, Andrew R.; Pennycook, S. J.; Dai, Sheng; Overbury, S. H. Journal of Physical Chemistry B ( 2005 ), 109 ( 21 ), 10676-10685 CODEN: JPCBFK ; ISSN: 1520-6106 . ( American Chemical Society ) Nanosized anatase (≤10 nm), rutile (≤10 nm), and brookite (∼70 nm) titania particles have been successfully synthesized via sonication and hydrothermal methods. Gold was deposited with high dispersion onto the surfaces of anatase, rutile, brookite, and com. titania (P25) supports through a deposition-pptn. (D-P) process. All catalysts were exposed to an identical sequence of treatment and measurements of catalytic CO oxidn. activity. The as-synthesized catalysts have high activity with concomitant Au redn. upon exposure to the reactant stream. Mild redn. at 423 K produces comparably high activity catalysts for every support. Deactivation of the four catalysts was obsd. following a sequence of treatments at temps. up to 573 K. The brookite-supported gold catalyst sustains the highest catalytic activity after all treatments. XRD and TEM results indicate that the gold particles supported on brookite are smaller than those on the other supports following the reaction and pretreatment sequences. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvFWgsb8%253D&md5=23b537cb7751e3457a7664ec946b1678
- 149 Ma, H. ; Yin, B. ; Wang, S. ; Jiao, Y. ; Pan, W. ; Huang, S. ; Chen, S. ; Meng, F. Synthesis of Silver and Gold Nanoparticles by a Novel Electrochemical Method . ChemPhysChem 2004 , 5 , 68 – 75 , DOI: 10.1002/cphc.200300900 149 Synthesis of silver and gold nanoparticles by a novel electrochemical method Ma, Houyi; Yin, Bingsheng; Wang, Shuyun; Jiao, Yongli; Pan, Wei; Huang, Shaoxin; Chen, Shenhao; Meng, Fanjun ChemPhysChem ( 2004 ), 5 ( 1 ), 68-75 CODEN: CPCHFT ; ISSN: 1439-4235 . ( Wiley-VCH Verlag GmbH & Co. KGaA ) Spherical silver and gold nanoparticles with narrow size distributions were conveniently synthesized in aq. soln. by a novel electrochem. method. The technol. keys to the electrochem. synthesis of monodispersed metallic nanoparticles lie in the choice of an ideal stabilizer for the metallic nanoclusters and the use of a rotating platinum cathode. Poly(N-vinylpyrrolidone) (PVP) was chosen as the stabilizer for the silver and gold clusters. PVP not only protects metallic particles from agglomeration, but also promotes metal nucleation, which tends to produce small metal particles. Using a rotating platinum cathode effectively solves the technol. difficulty of rapidly transferring the (electrochem. synthesized) metallic nanoparticles from the cathode vicinity to the bulk soln., avoiding the occurrence of flocculates in the vicinity of the cathode, and ensuring the monodispersity of the particles. The particle size and particle size distribution of the silver and gold nanoparticles were improved by adding sodium dodecyl benzene sulfonate (SDBS) to the electrolyte. The electrochem. synthesized nanoparticles were characterized by TEM and UV/Vis spectroscopy. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFKqtLg%253D&md5=340acffa742a7e7a19710a8859057d74
- 150 Fajar, M. N. ; Endarko, E. ; Rubiyanto, A. ; Malek, N. A. N. N. ; Hadibarata, T. ; Syafiuddin, A. A Green Deposition Method of Silver Nanoparticles on Textiles and Their Antifungal Activity . Biointerface Res. Appl. Chem. 2020 , 10 , 4902 – 4907 , DOI: 10.33263/BRIAC101.902907 150 A green deposition method of silver nanoparticles on textiles and their antifungal activity Fajar, Muhammad Noer; Endarko, Endarko; Rubiyanto, Agus; Malek, Nik Ahmad Nizam Nik; Hadibarata, Tony; Syafiuddin, Achmad Biointerface Research in Applied Chemistry ( 2020 ), 10 ( 1 ), 4902-4907 CODEN: BRACD5 ; ISSN: 2069-5837 . ( Comporter SRL ) This study aims to propose a new green method for the deposition of silver nanoparticles (AgNPs) on textiles without the use of chem. compds. as binders. The deposition of AgNPs on textiles was achieved by immersing textiles in silver nitrate soln. before adding with a natural reducing agent obtained from the extn. of Mikania micrantha. Plasmonic properties of the synthesized AgNPs were characterized using UV-visible (UV-vis) spectroscopy and surface morphol. of textiles was identified using the field-emission SEM (FESEM). In addn., energy-dispersive X-ray spectroscopy was also employed for the characterization. Inhibition zone measurement was performed for evaluating the antifungal capability of textiles attached with AgNPs. This study showed that the attachment of AgNPs to several textile types (cotton, cotton-polyester, silk, and fiber) without the use of binders or other chem. compds. had been successfully achieved. Moreover, all textiles attached with AgNP exhibited effective antifungal activity. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlOmtb3I&md5=2dc56f4934009ffb0a28e08e8a0f964d
- 151 Chandra, A. ; Bhattarai, A. ; Yadav, A. K. ; Adhikari, J. ; Singh, M. ; Giri, B. Green Synthesis of Silver Nanoparticles Using Tea Leaves from Three Different Elevations . ChemistrySelect 2020 , 5 , 4239 – 4246 , DOI: 10.1002/slct.201904826 151 Green Synthesis of Silver Nanoparticles Using Tea Leaves from Three Different Elevations Chandra, Abhishek; Bhattarai, Ajaya; Yadav, Ashok K.; Adhikari, Janak; Singh, Man; Giri, Basant ChemistrySelect ( 2020 ), 5 ( 14 ), 4239-4246 CODEN: CHEMUD ; ISSN: 2365-6549 . ( Wiley-VCH Verlag GmbH & Co. KGaA ) Green synthesis of nanoparticles offers numerous advantages over the conventional methods. This work provides a comprehensive understanding on the effect of tea cultivation elevation on the formation of silver nanoparticles (AgNPs) using green tea (Camellia Sinensis) leaves. The green tea leaves were collected from three different elevations: 86, 1700, and 2000 m above sea level in eastern Nepal. We found that AgNPs synthesized using tea leaves from 1700 m were homogeneously dispersed and smallest size, when compared to AgNPs synthesized using tea leaves from remaining two elevations. All aq. dispersed AgNPs were sensitive towards mercury (II) ion over a range of other metal ions tested. However, the AgNPs synthesized using tea leaves from 1700 m resulted in better detection limit of 9.79 muM for sensing mercury (II) ions. Interestingly, the nanoparticles when addnl. stabilized in aq. trimethyloctylammonium bromide, a cationic surfactant among seven other surfactants tested, improved the detection limit to 0.71 muM. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXksFelsbo%253D&md5=fda1579f39fd69d71a8d310ddd6e1adc
- 152 Salehizadeh, H. ; Hekmatian, E. ; Sadeghi, M. ; Kennedy, K. Synthesis and Characterization of Core-Shell Fe3O4-Gold-Chitosan Nanostructure . J.Nanobiotechnol. 2012 , 10 , 3 , DOI: 10.1186/1477-3155-10-3 152 Synthesis and characterization of core-shell Fe3O4-gold-chitosan nanostructure Salehizadeh, Hossein; Hekmatian, Elham; Sadeghi, Meisam; Kennedy, Kevin Journal of Nanobiotechnology ( 2012 ), 10 ( ), 3 CODEN: JNOAAO ; ISSN: 1477-3155 . ( BioMed Central Ltd. ) Fe3O4-gold-chitosan core-shell nanostructure can be used in biotechnol. and biomedical applications such as magnetic biosepn., water and wastewater treatment, biodetection and bioimaging, drug delivery, and cancer treatment. Magnetite nanoparticles with an av. size of 9.8 nm in diam. were prepd. using by pptn. A gold-coated Fe3O4 monotonous core-shell nanostructure was produced with an av. size of 15 nm in diam. by glucose redn. of Au3+ which is then stabilized with a chitosan cross linked by formaldehyde. The results of analyses with x-ray diffraction (XRD), FTIR, TEM, and AFM indicated that the nanoparticles were regularly shaped, and agglomerate-free, with a narrow size distribution. Conclusions: A rapid, mild method for synthesizing Fe3O4-gold nanoparticles using chitosan was investigated. A magnetic core-shell-chitosan nanocomposite, including both the supermagnetic properties of iron oxide and the optical characteristics of colloidal gold nanoparticles, was prepd. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xjs1eju7k%253D&md5=c9b35a3aabd425191c40989d2e0f14a1
- 153 Bruchez, M. ; Moronne, M. ; Gin, P. ; Weiss, S. ; Alivisatos, A. P. Semiconductor Nanocrystals as Fluorescent Biological Labels . Science 1998 , 281 , 2013 – 2016 , DOI: 10.1126/science.281.5385.2013 153 Semiconductor nanocrystals as fluorescent biological labels Bruchez, Marcel, Jr.; Moronne, Mario; Gin, Peter; Weiss, Shimon; Alivisatos, A. Paul Science (Washington, D. C.) ( 1998 ), 281 ( 5385 ), 2013-2016 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) Semiconductor nanocrystals were prepd. for use as fluorescent probes in biol. staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, sym. emission spectrum and are photochem. stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual-emission, single-excitation labeling expt. on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKgurw%253D&md5=db36fdbbfbc2facf264c3f98c1c8efcb
- 154 Chan, W. C. W. ; Nie, S. Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection . Science 1998 , 281 , 2016 – 2018 , DOI: 10.1126/science.281.5385.2016 154 Quantum dot bioconjugates for ultrasensitive nonisotopic detection Chan, Warren C. W.; Nile, Shuming Science (Washington, D. C.) ( 1998 ), 281 ( 5385 ), 2016-2018 CODEN: SCIEAS ; ISSN: 0036-8075 . ( American Association for the Advancement of Science ) Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomols. for use in ultra-sensitive biol. detection. In comparison with org. dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-sol. and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomols. recognized specific antibodies or antigens. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKnsrk%253D&md5=481c7a81438f03ca6c871d30afde6eb3
- 155 Dubertret, B. ; Calame, M. ; Libchaber, A. J. Single-Mismatch Detection Using Gold-Quenched Fluorescent Oligonucleotid . Nat. Biotechnol. 2001 , 19 , 365 – 370 , DOI: 10.1038/86762 155 Single-mismatch detection using gold-quenched fluorescent oligonucleotides Dubertret, Benoit; Calame, Michel; Libchaber, Albert J. Nature Biotechnology ( 2001 ), 19 ( 4 ), 365-370 CODEN: NABIF9 ; ISSN: 1087-0156 . ( Nature America Inc. ) Here we describe a hybrid material composed of a single-stranded DNA (ssDNA) mol., a 1.4 nm diam. gold nanoparticle, and a fluorophore that is highly quenched by the nanoparticle through a distance-dependent process. The fluorescence of this hybrid mol. increases by a factor of as much as several thousand as it binds to a complementary ssDNA. We show that this composite mol. is a different type of mol. beacon with a sensitivity enhanced up to 100-fold. In competitive hybridization assays, the ability to detect single mismatch is eightfold greater with this probe than with other mol. beacons. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXis1Smsbk%253D&md5=47167a2f825fd18295e2a7f8d67988bc
- 156 Reynolds, R. A. ; Mirkin, C. A. ; Letsinger, R. L. Homogeneous, Nanoparticle-Based Quantitative Colorimetric Detection of Oligonucleotides . J. Am. Chem. Soc. 2000 , 122 , 3795 – 3796 , DOI: 10.1021/ja000133k 156 Homogeneous, Nanoparticle-Based Quantitative Colorimetric Detection of Oligonucleotides Reynolds, Robert A., III; Mirkin, Chad A.; Letsinger, Robert L. Journal of the American Chemical Society ( 2000 ), 122 ( 15 ), 3795-3796 CODEN: JACSAT ; ISSN: 0002-7863 . ( American Chemical Society ) A modified method for a heterogeneous colorimetric oligonucleotide detection system based on alkylthiol-functionalized oligonucleotide-modified gold probes is described. Gold particles (50 and 100 nm) are modified and stabilized using dithiane epiandrosterone-functionalized oligonucleotides. Assay sensitivity and larger detection ranges are increased with increasing particle size. While the 100 nm gold probes are more sensitive to lower oligonucleotide concns. than the 50 nm probes, adequate endpoints were not obtainable with the 100 nm probes due to aggregate sedimentation. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXitFGjsbc%253D&md5=30204f1197a9b90f97eadd06489f7e08
- 157 Alivisatos, A. P. ; Johnsson, K. P. ; Peng, X. ; Wilson, T. E. ; Loweth, C. J. ; Bruchez, M. P. ; Schultz, P. G. Organization of “nanocrystal Molecules” Using DNA . Nature 1996 , 382 , 609 – 611 , DOI: 10.1038/382609a0 157 Organization of 'nanocrystal molecules' using DNA Alivisatos, A. Paul; Johnsson, Kai P.; Peng, Xiaogang; Wilson, Troy E.; Loweth, Colin J.; Bruchez, Marcel P., Jr.; Schultz, Peter G. Nature (London) ( 1996 ), 382 ( 6592 ), 609-611 CODEN: NATUAS ; ISSN: 0028-0836 . ( Macmillan Magazines ) The authors describe a strategy for the synthesis of 'nanocrystal mols.', in which discrete nos. of Au nanocrystals are organized into spatially defined structures based on Watson-Crick base-pairing interactions. The authors attach single-stranded DNA oligonucleotides of defined length and sequence to individual nanocrystals, and these assemble into dimers and trimers on addn. of a complementary single-stranded DNA template. The authors anticipate that this approach should allow the construction of more complex two- and three-dimensional assemblies. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XltVWqsrY%253D&md5=27e1eb981a0cfd51907eff5a5a105f50
- 158 He, W. ; Zhou, Y. T. ; Wamer, W. G. ; Boudreau, M. D. ; Yin, J. J. Mechanisms of the PH Dependent Generation of Hydroxyl Radicals and Oxygen Induced by Ag Nanoparticles . Biomaterials 2012 , 33 , 7547 – 7555 , DOI: 10.1016/j.biomaterials.2012.06.076 158 Mechanisms of the pH dependent generation of hydroxyl radicals and oxygen induced by Ag nanoparticles He, Weiwei; Zhou, Yu-Ting; Wamer, Wayne G.; Boudreau, Mary D.; Yin, Jun-Jie Biomaterials ( 2012 ), 33 ( 30 ), 7547-7555 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) Many of the chem. and biol. effects of silver nanoparticles (Ag NPs) are attributed to the generation of reactive oxygen species (ROS). ESR spectroscopy was used to provide direct evidence for generating ROS during decompn. of H2O2 assisted by Ag NPs. Hydroxyl radical formation was obsd. under acidic conditions and was accompanied by dissoln. of Ag NPs. In contrast, evolution of O2 was obsd. in alk. solns. contg. H2O2 and Ag NPs; however, no net dissoln. of Ag NPs was obsd. due to re-redn. of Ag+ as evidenced by a cyclic reaction. Since H2O2 is a biol. relevant product being continuously generated in cells, these results obtained under conditions mimicking different biol. microenvironments may provide insights for finding new biomedical applications for Ag NPs and for risk assessment. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtVKnur3L&md5=2f904d76a059d32c69310bcfb930ddc9
- 159 Arora, S. ; Jain, J. ; Rajwade, J. M. ; Paknikar, K. M. Cellular Responses Induced by Silver Nanoparticles: In Vitro Studies . Toxicol. Lett. 2008 , 179 , 93 – 100 , DOI: 10.1016/j.toxlet.2008.04.009 159 Cellular responses induced by silver nanoparticles: In vitro studies Arora, S.; Jain, J.; Rajwade, J. M.; Paknikar, K. M. Toxicology Letters ( 2008 ), 179 ( 2 ), 93-100 CODEN: TOLED5 ; ISSN: 0378-4274 . ( Elsevier B.V. ) A systematic study on the in vitro interactions of 7-20 nm spherical silver nanoparticles (SNP) with HT-1080 and A431 cells was undertaken as a part of an on-going program in our lab. to develop a topical antimicrobial agent for the treatment of burn wound infections. Upon exposure to SNP (up to 6.25 μg/mL), morphol. of both the cell types remained unaltered. However, at higher concns. (6.25-50 μg/mL) cells became less polyhedral, more fusiform, shrunken and rounded. IC50 values for HT-1080 and A431 as revealed by XTT assay were 10.6 and 11.6 μg/mL, resp. When the cells were challenged with ∼1/2 IC50 concn. of SNP (6.25 μg/mL), clear signs of oxidative stress, i.e. decreased GSH (∼2.5-folds in HT-1080, ∼2-folds in A431) and SOD (∼1.6-folds in HT-1080, 3-folds in A431) as well as increased lipid peroxidn. (∼2.5-folds in HT-1080, ∼2-folds in A431) were seen. Changes in the levels of catalase and GPx in A431 cells were statistically insignificant in both cell types. DNA fragmentation in SNP-exposed cells suggested apoptosis. When the apoptotic thresholds of SNP were monitored with caspase-3 assay the concns. required for the onset of apoptosis were found to be much lower (0.78 μg/mL in HT-1080, 1.56 μg/mL in A431) than the necrotic concn. (12.5 μg/mL in both cell types). These results can be used to define a safe range of SNP for the intended application as a topical antimicrobial agent after appropriate in vivo studies. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmsFKrtrw%253D&md5=2de234ca0852a0e3305120e2e4cf7b3a
- 160 Yang, E. J. ; Kim, S. ; Kim, J. S. ; Choi, I. H. Inflammasome Formation and IL-1β Release by Human Blood Monocytes in Response to Silver Nanoparticles . Biomaterials 2012 , 33 , 6858 – 6867 , DOI: 10.1016/j.biomaterials.2012.06.016 160 Inflammasome formation and IL-1β release by human blood monocytes in response to silver nanoparticles Yang, Eun-Jeong; Kim, Seungjae; Kim, Jong Soo; Choi, In-Hong Biomaterials ( 2012 ), 33 ( 28 ), 6858-6867 CODEN: BIMADU ; ISSN: 0142-9612 . ( Elsevier Ltd. ) In this study, the immunol. effect of silver nanoparticles on innate immunity was investigated using primary human monocytes. After exposure to silver nanoparticles, prodn. of IL-1β, a crit. cytokine involved in induction of innate immunity, significantly increased as particle size decreased. These results suggest that silver nanoparticles may evoke an immunol. active state. The size effect of silver nanoparticles on IL-1β prodn. was also further investigated. 5 Nm and 28 nm silver nanoparticles induced inflammasome formation and subsequent caspase-1 activation. Using inhibitors, we found exposure to silver nanoparticles caused leakage of cathepsins from lysosomes and efflux of intracellular K+. These two events induced superoxide within mitochondrial membranes, leading to inflammasome formation. 5 Nm silver nanoparticles produced more hydrogen peroxide and were more cytotoxic than 28 nm silver nanoparticles, suggesting the balance between superoxide and hydrogen peroxide governs cell fate, death or activation. Moreover, these findings also suggest that the immunol. significance of silver nanoparticles should be considered with respect to their capacity to synergistically activate immune responses. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xps1Klsrw%253D&md5=2ab339ae718603168c8524753f906433
- 161 Almofti, M. R. ; Ichikawa, T. ; Yamashita, K. ; Terada, H. ; Shinohara, Y. Silver Ion Induces a Cyclosporine A-Insensitive Permeability Transition in Rat Liver Mitochondria and Release of Apoptogenic Cytochrome C . J. Biochem. 2003 , 134 , 43 – 49 , DOI: 10.1093/jb/mvg111 161 Silver ion induces a cyclosporin A-insensitive permeability transition in rat liver mitochondria and release of apoptogenic cytochrome c Almofti, Mohamad Radwan; Ichikawa, Tomokazu; Yamashita, Kikuji; Terada, Hiroshi; Shinohara, Yasuo Journal of Biochemistry ( 2003 ), 134 ( 1 ), 43-49 CODEN: JOBIAO ; ISSN: 0021-924X . ( Japanese Biochemical Society ) Various reagents are known to open the mitochondrial permeability pore (PTP) and induce a permeability transition (PT), releasing apoptogenic proteins from the intermembrane space and triggering apoptosis. In this study, we examd. the effect of Ag+, a known cytotoxic sulfhydryl-reactive heavy metal, on isolated rat liver mitochondria. The following results were obtained: (1) Upon addn., Ag+ instantly induced mitochondrial swelling and acceleration of respiration. (2) Cyclosporin A, a specific inhibitor of classical PT, was ineffective against the effect of Ag+, indicating that silver ions induced non-classic PT. (3) Sulfhydryl reagents such as reduced glutathione completely inhibited the effects of Ag+ on the mitochondria. (4) Exptl. results using polyethylene glycol indicated that Ag+ induced opening of a pore in the inner mitochondrial membrane, which could be PTP of another open state or a distinct pore. (5) Electron microscopic anal. of mitochondria treated with Ag+ showed a novel mitochondrial configuration that was apparently different from that of normal mitochondria or Ca2+-treated mitochondria. (6) Ag+ also induced the release of apoptogenic cytochrome c in a CsA-insensitive but GSH-sensitive manner. These results suggest that Ag+ promotes a nonclassical permeability increase in the mitochondrial inner membrane that is clearly distinguishable from the classical PT and releases apoptogenic cytochrome c in a classical PT-independent manner. >> More from SciFinder ® https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnslGluro%253D&md5=2c4e18ddcebbf9b2fda1f76c6748298c
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Innovative eco-friendly silver nanoparticles: various synthesis methods, characterization and prospective applications
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Silver Nanoparticles (AgNP) are highly sought after due to their unique properties and wide-ranging applications across various industries, including medicine, electronics, catalysis, and environmental cleanup. However, traditional AgNP preparation methods involving hazardous chemicals and energy-intensive processes pose threats to the environment and human health. This review focuses on environmentally friendly techniques for AgNP preparation, such as using medicinal herbs, microbes, polymers, and eco-friendly solvents. Utilizing biodegradable polymers and natural materials reduces the reliance on harmful chemicals, mitigating their adverse environmental impacts. Plant extracts play a crucial role in AgNP production due to their inherent stabilizing and reducing properties. Microorganisms like bacteria, fungi, and algae also show promise in generating AgNP owing to their natural reducing abilities. Biopolymers such as enzymes, carbohydrates, and DNA act as both capping agents and stabilizers for nanoparticles, preventing aggregation. The review highlights the numerous advantages of employing environmentally friendly methods in AgNP production. These applications span various fields, including cancer therapies, antibacterial and antifungal medications, sensors, catalysts, and water filtration systems. AgNP possess unique qualities suitable for diverse uses, including their surface-enhanced Raman scattering (SERS) impact and catalytic properties. The review encourages further research in this area to develop eco-friendly nanomaterials through improved green synthesis techniques and broader applications. Green synthesis techniques for AgNP present a viable and eco-friendly alternative to conventional methods. In general, environmentally friendly synthesis techniques for synthesizing AgNP have an immense potential for scientific progress and can lead to a wide range of applications.
- biopolymers
- green synthesis
- green solvents
- microorganisms
- plant extracts
- water purification
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QBD APPROACH FOR GREEN SYNTHESIS OF RUTIN SILVER NANOPARTICLES- SCREENING FOR ANTIOXIDANT, ANTICANCER AND ANTICLASTOGENIC POTENTIAL
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- Silver nanoparticles
- Drug release
- Antioxidant
Introduction
Materials and methods:, reagents and kits, extraction, isolation and characterization of rutin from carica papaya leaves.
S. no | Extract | Methanol extract | Chloroform extract | Hexane extract |
---|
1 | Yield | 118.6 | 85.9 | 58.6 |
2 | Color | Reddish brown | Dark brown | Yellowish brown |
3 | Nature | Semisolid | Semisolid | semisolid |
Variable | Name | Units | Low | Medium | High |
---|
X1 | Silver nitrate solution | ml | 4 | 7 | 10 |
X2 | Methanol | ml | 20 | 25 | 30 |
X3 | Sonication time | min | 5 | 7.5 | 10 |
Dependent variable | Factor | Units | Constraint | |
Y1 | Particle size | Y1 | Nm | Minimize | |
Y2 | Entrapment efficiency | Y2 | % | Maximize | |
Y3 | Cumulative drug release | Y3 | % | Maximize | |
Design of Experiment (DoE) for optimization of Rutin silver nanoparticles
Std | Rutin | Factor X1 3 (ml) | FactorX2 B: solvent (ml) | FactorX3 C:Sonication time(min) | Response Y1 Particle size (nm) | Response Y2 Entrapment efficiency (%) | Response Y3 CDR% |
---|
1 | 1 | 4 | 20 | 5 | 89.2±0.021 | 86.3±0.23 | 86.1±0.187 |
5 | 2 | 4 | 20 | 10 | 152±0.01 | 76.5±0.21 | 83.2±0.1870.064 |
13 | 3 | 7 | 25 | 3.29552 | 123±0.03 | 78.4±0.25 | 85.1±0.25 |
7 | 4 | 4 | 30 | 10 | 112±0.1 | 82.2±0.28 | 81.1±0.123 |
12 | 5 | 7 | 33.409 | 7.5 | 147±0.02 | 86.7±0.21 | 92.6±0.143 |
11 | 6 | 7 | 16.591 | 7.5 | 169±0.01 | 75.4±0.15 | 82.1±0.031 |
15 | 7 | 7 | 25 | 7.5 | 154±0.05 | 79.1±0.18 | 83.5±0.153 |
9 | 8 | 1.95462 | 25 | 7.5 | 132±0.02 | 81.3±0.24 | 91.7±0.080 |
3 | 9 | 4 | 30 | 5 | 125±0.015 | 76.6±0.26 | 96.6±0.053 |
2 | 10 | 10 | 20 | 5 | 148±0.22 | 89.3±0.12 | 93.6±0.035 |
8 | 11 | 10 | 30 | 10 | 165±0.26 | 85.5±0.18 | 94.8±0.665 |
6 | 12 | 10 | 20 | 10 | 126.34±0.28 | 88.2±0.023 | 97.3±0.041 |
10 | 13 | 12.0454 | 25 | 7.5 | 187±0.21 | 81.6±0.56 | 92.4±0.153 |
4 | 14 | 10 | 30 | 5 | 256±0.45 | 82.1±0.16 | 93.5±0.023 |
14 | 15 | 7 | 25 | 11.7045 | 235±0.23 | 83.1±0.15 | 97.3±0.056 |
Green synthesis of Rutin silver nanoparticles- concentration variation method
Characterization of the Rutin Nanoformulation:
C-position | δ C values |
---|
2 | 156.3 |
3 | 133.2 |
4 | 177.3 |
5 | 156.5 |
6 | 98.6 |
7 | 164.0 |
8 | 93.5 |
9 | 161.1 |
10 | 103.8 |
1 | 121.5 |
2 | 115.1 |
3 | 144.6 |
4 | 148.3 |
5 | 116.2 |
6 | 121.1 |
1'' | 100.7 |
2'' | 74.9 |
3'' | 76.3 |
4'' | 71.7 |
5'' | 75.7 |
6'' | 67.9 |
1''' | 102.2 |
2''' | 70.8 |
3''' | 70.2 |
4''' | 70.4 |
5''' | 68.1 |
6''' | 17.7 0 |
S. no | Mean (mV) |
---|
1 | -22±0.25 |
2 | 32±0.01 |
3 | 23±0.02 |
4 | 35±0.01 |
5 | 47±0.05 |
6 | 49±0.01 |
7 | 34±0.05 |
8 | 32±0.21 |
9 | 25±0.018 |
10 | 44±0.20 |
11 | 35±0.27 |
12 | -28.6±0.24 |
13 | -27±0.23 |
14 | 36±0.42 |
15 | -35±0.13 |
Source | Sum of Squares | Df | Mean Square | F-value | p-value | |
---|
Model | 18348.09 | 9 | 2038.68 | 1.11 | 0.4794 | Significant |
A-Silver nitrate | 7029.43 | 1 | 7029.43 | 3.83 | 0.1077 | |
B-Methanol | 817.48 | 1 | 817.48 | 0.4455 | 0.5340 | |
C-Sonication time | 1156.98 | 1 | 1156.98 | 0.6306 | 0.4631 | |
AB | 2837.30 | 1 | 2837.30 | 1.55 | 0.2688 | |
AC | 3307.28 | 1 | 3307.28 | 1.80 | 0.2371 | |
BC | 2640.46 | 1 | 2640.46 | 1.44 | 0.2840 | |
A | 63.57 | 1 | 63.57 | 0.0346 | 0.8597 | |
B | 86.08 | 1 | 86.08 | 0.0469 | 0.8371 | |
C | 80.80 | 1 | 80.80 | 0.0440 | 0.8421 | |
Residual | 9173.86 | 5 | 1834.77 | | | |
Cor Total | 27521.95 | 14 | | | | |
Determination of Entrapment efficiency
S. no | Concentration μg/ml | Absorbance values | Standard deviation | | |
---|
Trial 1 | Trial 2 | Trial 3 | Avg |
---|
1 | 20 | 0.203 | 0.202 | 0.201 | 0.2018 | 0.001041 | SE | 0.05869 |
2 | 40 | 0.392 | 0.393 | 0.398 | 0.3933 | 0.004163 | SD | 0.17607 |
3 | 60 | 0.621 | 0.631 | 0.661 | 0.6376 | 0.020817 | LOD | 32.2795 |
4 | 80 | 0.781 | 0.812 | 0.813 | 0.802 | 0.018193 | LOQ | 97.8167 |
5 | 100 | 0.931 | 0.928 | 0.905 | 0.9213 | 0.014224 | | |
Invitro Drug release studies – Dissolution studies
Drug kinetic model | F12 | Rutin | Plot | Equation |
---|
Zero order | 0.9504 | 0.8551 | Q vs t | Q = K t |
First order | 0.9836 | 0.9774 | In(Q - Q ) vs t | In Q In Q - K t |
Higuchi | 0.9831 | 0.9432 | Q vs t | Q =K t |
Korsmeyer peppas | 0.9771 | 0.9564 | Q vs log t | ln(Qt)=ln(kKP)+nln(t) |
Invitro antioxidant activity
Dpph free radical scavenging assay.
Conc | log conc | Rutin silver nanoparticles | Rutin | STD |
---|
10 | 1 | 4.7±0.03 | 1.7±0.01 | 41.7±0.03 |
20 | 1.30103 | 22.9±0.04 | 19.4±0.01 | 51.8±0.02 |
30 | 1.4771213 | 35.4±0.01 | 27.2±0.02 | 81.9±0.01 |
40 | 1.60206 | 42.8±0.03 | 42.5±0.04 | 89.4±0.03 |
50 | 1.69897 | 51.5±0.021 | 48.6±0.03 | 94.6±0.02 |
IC | | 49.7±0.013 | 56.1±0.015 | 30.6±0.02 |
Reducing power assay
Conc (μg/ml) | log conc | Rutin | Rutin silver nanoparticles | STD |
---|
20 | 1 | 0.41±0.01 | 0.36±0.01 | 0.49±0.011 |
40 | 1.30103 | 0.49±0.03 | 0.53±0.022 | 0.56±0.022 |
60 | 1.47712 | 058±0.01 | 0.62±0.013 | 0.68±0.032 |
80 | 1.60206 | 0.69±0.03 | 0.79±0.015 | 0.89±0.021 |
100 | 1.69897 | 0.86±0.02 | 0.92±0.018 | 0.956±0.014 |
In vitro anticancer activity on G361 and MCF7 cell line- MTT assay
Growth and maintenance, assay procedure.
| MCF 7 (Breast Cancer Cell Line) | G361 cell line (Human skin melanoma cell line) |
---|
S. no | Concentration μg/ml | Rutin silver nanoparticles | Doxorubicin | Rutin silver nanoparticles | Doxorubicin |
---|
1 | 2.5 | 8.9±0.010 | 20.8±0.011 | 6.3±0.011 | 25.3±0.013 |
2 | 5 | 15.2±0.021 | 55.3±0.018 | 12.2±0.026 | 56.2±0.012 |
3 | 10 | 12.4±0.011 | 62.8±0.025 | 18.4±0.015 | 72.5±0.024 |
4 | 50 | 25.8±0.03 | 72.3±0.042 | 32.8±0.034 | 83.2±0.041 |
5 | 100 | 38.6±0.024 | 79.6±0.036 | 45.6±0.022 | 89.6±0.03 |
6 | 200 | 46.3±0.032 | 86.5±0.021 | 49.3±0.035 | 93.1±0.022 |
| IC value | 29.65±3.26 | 110.24±2.65 | 118.36±1.65 | 36.9±2.45 |
Animals used in experiments
In vivo toxicity studies, acute oral toxicity studies, bone marrow micronucleus test, administration and regimen.
Treatment (mg/kg) | MNPCE (%) | Total MN (%) | PCE/NCE |
---|
Control (0.9% saline) | 0.0.15 ± 0.09 | 0.08 ± 0.012 | 1.56 ± 0.036 |
Positive control (CP-40) | 4.12 ± 0.135** | 2.84 ± 0.052** | 0.89 ± 0.017** |
F12-100 | 0.13 ± 0.07 | 0.06 ± 0.024 | 1.74 ± 0.012 |
F12-200 | 0.10 ± 0.013 | 0.05 ± 0.011 | 1.58 ± 0.006 |
F12-100 + CP-40 | 2.57 ± 0.041 | 0.74 ± 0.013 | 0.85 ± 0.037 |
F12-200 + CP-40 | 1.54 ± 0.004 | 0.56 ± 0.011 | 0.62 ± 0.014 |
Statistical analysis
3 results and discussion, extraction, isolation of rutin-3-o glycoside from methanolic extract of carica papaya leaves, characterisation of rutin.
Experimental design and optimization
Effect of independent variables on particle size.
Effect of Independent variables on Entrapment efficiency
Source | Sum of Squares | Df | Mean Square | F-value | p-value | |
---|
Model | 122.20 | 9 | 13.58 | 0.6109 | 0.7549 | significant |
A-Silver nitrate | 26.45 | 1 | 26.45 | 1.19 | 0.3251 | |
B-Methanol | 7.48 | 1 | 7.48 | 0.3364 | 0.5871 | |
C-Sonication time | 0.0739 | 1 | 0.0739 | 0.0033 | 0.9563 | |
AB | 0.1012 | 1 | 0.1012 | 0.0046 | 0.9488 | |
AC | 0.2813 | 1 | 0.2813 | 0.0127 | 0.9148 | |
BC | 77.50 | 1 | 77.50 | 3.49 | 0.1208 | |
A | 9.18 | 1 | 9.18 | 0.4130 | 0.5488 | |
B | 7.19 | 1 | 7.19 | 0.3236 | 0.5941 | |
C | 5.86 | 1 | 5.86 | 0.2637 | 0.6295 | |
Residual | 111.12 | 5 | 22.22 | | | |
CorTotal | 233.32 | 14 | | | | |
Effect of independent variable on cumulative drug release
Source | Sum of Squares | Df | Mean Square | F-value | p-value | |
---|
Model | 309.52 | 9 | 34.39 | 0.9907 | 0.5350 | significant |
A-Silver nitrate | 81.57 | 1 | 81.57 | 2.35 | 0.1859 | |
B-Methanol | 40.30 | 1 | 40.30 | 1.16 | 0.3305 | |
C-Sonication time | 3.71 | 1 | 3.71 | 0.1069 | 0.7570 | |
AB | 15.12 | 1 | 15.12 | 0.4357 | 0.5384 | |
AC | 68.45 | 1 | 68.45 | 1.97 | 0.2192 | |
BC | 28.12 | 1 | 28.12 | 0.8102 | 0.4093 | |
A | 56.96 | 1 | 56.96 | 1.64 | 0.2564 | |
B | 11.96 | 1 | 11.96 | 0.3447 | 0.5827 | |
C | 46.35 | 1 | 46.35 | 1.34 | 0.3001 | |
Residual | 173.56 | 5 | 34.71 | | | |
CorTotal | 483.08 | 14 | | | | |
Green synthesis of silver nanoparticles of Rutin
Characterization of rutin silver nanoparticles, particle morphology-dls, ftir and uv –vis studies:.
SEM and XRD for solid state stability
In vitro drug release studies.
Invitro Antioxidant Activity of Optimized Rutin Silver Nanoparticles (F12)
Invitro anticancer activity on mcf7 and g361 cell line, acute oral toxicity study and effect of f12 on cyclophosphamide induced mn in bone marrow (bm) cells of mice.
Ethical statement
Declaration of competing interest, data and code availability, list of abbreviations, article metrics, related articles.
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Synthesis of TiO 2 nanoparticles by chemical and green synthesis methods and their multifaceted properties
- Research Article
- Open access
- Published: 03 March 2021
- Volume 3 , article number 409 , ( 2021 )
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- M. Aravind 1 , 3 ,
- M. Amalanathan ORCID: orcid.org/0000-0001-8030-0086 1 , 3 &
- M. Sony Michael Mary 2 , 3
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In this present work, Titanium dioxide nanoparticles (TiO 2 NPs) successfully synthesized using the chemical as well as the green synthesis routine. The ethanol provoked the chemical reduction of ions. In the green synthesis, jasmine flower extract was used as a reducing and stabilizing agent because it contains alkaloids, coumarins, flavonoids. The Rutile phase of TiO 2 NPs with an average crystalline size of 31–42 nm was revealed from the XRD pattern. From the UV–Visible spectroscopy, the optically active region of TiO 2 NPs at 385 nm represents the visible region spectrum. The Ti–O–Ti and Ti–O vibration bond formation confirms the formation of TiO 2 NPs. The SEM image of TiO 2 NPs reveals that the spherical shaped NPs with randomly arranged manner. The obtained results have revealed that the property of TiO 2 nanoparticles was similar in both processes. The Photodegradation of methylene blue dye was investigated and resulted in the maximum degradation efficiency of 92% is achieved at 120 min of irradiation. The Photodegradation study shows the biosynthesized TiO 2 NPs exhibits a higher degradation efficiency compared to chemically synthesized TiO 2 NPs. The antibacterial activity of prepared TiO 2 NP’s was studied using grams-positive and gram-negative strains. The biological activities of green synthesized TiO 2 NPs are enhanced compared to the chemically synthesized TiO 2 NPs. Hence the degradation efficiency and zone inhibition layer indicate that the prepared TiO 2 NPs are the potential candidate for environmental and biomedical applications.
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1 Introduction
Nanomaterials belongs to the range of below 100 nm has unique chemical, physical, electrical, and mechanical properties and also diversely utilized in the field of medical, biotechnology, microbiology, pharmaceutics and chemistry, engineering, inexpensive catalyst, cytotoxicity study, etc. [ 1 , 2 , 3 ]. Owing to its large surface area, nanomaterial synthesis methods are classified into the physical and chemical methods. However, these methods are not suitable for medicinal and biological applications because of its harmful nature to the environment. Therefore, researchers are going for a green synthesis route to prepare nanomaterials because the green synthesis approach is simple, eco-friendly, and cost-effective [ 4 , 5 ]. Green synthesis is a fascinating method for material science [ 6 , 7 , 8 ].In the past few decades, metal oxide semiconductors such as ZnO, MgO, CuO, CdO, NiO, etc. were widely used, and it is prepared via physical, chemical, and biological methods. Among them, TiO 2 NPs are a well-known semiconductor with a wide bandgap of 3.2 eV for anatase and 3.0 eV for rutile phase [ 9 ], but the brookite phase is rare to obtain [ 10 ]. The Anatase and rutile phase of TiO 2 exhibits a tetragonal crystal structure, but the brookite phase is an orthorhombic structure [ 11 ]. The transition metal oxide, mainly TiO 2 , is widely used in cosmetics, photocatalysts, medicines, sensors, and solar cell applications because of its peculiar properties like interconnected pores and large surface area [ 12 ].
Nowadays, the metal and metal oxide nanoparticles are synthesized by chemical as well as physical methods such as the microwave [ 13 ], hydrothermal [ 14 ], solid-state [ 15 ], solution route method [ 16 ], sol–gel [ 17 ] chemical phase decomposition vapour [ 18 ], solvothermal crystallization [ 19 ], ultrasonic irradiation and [ 20 ], and green synthesis method [ 21 ]. Nevertheless, these methods generate heterogeneous NPs with high energy consumption and also the chemicals process involves synthetic capping, reducing, and stabilizing agents which results in the creation of anti-environmentally safe by-products [ 22 ]. In recent years researchers are focussed on the green synthesis route to the synthesis of metal and metal oxide nanoparticles. The bio-mediated metal and metal oxide NP's shows potential application on drug delivery, nanocatalyst, nano-medicine, biosensor, biotechnology, and microbiology. The green synthesis method is similar to the chemical reduction process, where the costly chemical reagents are replaced by plant extracts and microorganisms and also reduces the toxicity, which enhances its biomedical applications.
The bio-mediated TiO 2 NPs exhibit excellent antibacterial, anti-inflammatory, anti-fungal, anti-microbial, and several biological activities. The decomposition of microorganisms by its photo-semiconductor properties results in the enhancement of biological activities [ 23 ]. There are numerous reports on the preparation of TiO 2 NPs from Cinnamon Powder [ 9 ] , Mangifera indica [ 24 ] Citrus reticulate [ 25 ] Azadirachtaindica leaf [ 26 ] Murayakoenigii [ 27 ] Curcuma longa [ 28 ] , Cynodondactylon [ 1 ] , Annona squamosa [ 29 ] , Morindacitrifolia [ 30 ] , Psidium guajava [ 31 ] , Jatropha curcas [ 32 ] , Fungus-mediated [ 33 ] towards the biological applications. Moreover, the morphology, size, shape, porosity, and crystallinity depend upon the concentration of precursor and temperature [ 34 ].
This present study is to investigate the chemical and bio-synthesis of the TiO 2 nanoparticles. The phytochemicals present in jasmine flower extracts are alkaloids, coumarins, flavonoids, tannins, terpenoids, glycosides, embodies, steroids, essential oil, and saponins [ 35 ]. These phytochemicals are responsible for the reduction of Titanium tetra Isopropoxide to titanium dioxide nanoparticles. The structural, morphological, vibrational, and optical properties of the TiO 2 NPs were analyzed. The photodegradation of methylene blue dye were visualized uisng UV-Visible irradiation technique. As well as the antibacterial activity were tested against both gram-positive and gram-negative strains . The different processes of TiO 2 nanoparticles synthesis were studied in detail.
2 Materials and methods
2.1 materials.
Titanium Tetra Isopropoxide (TTIP, C 12 H 28 O 4 Ti, 97%), Ethanol (C 2 H 5 OH, 96%), Methylene blue (C 16 H 18 CIN 3 S), and distilled water was purchased from Merck India. Jasmine flowers were collected from the local market. All chemicals and reagents are of analytic grade and used without further purification. Bacterial pathogens, such as Staphylococcus aureus (gram-positive bacteria), Klebsiella pneumonia and E-coli (gram-negative bacteria) were used to study biological activities.
2.2 Synthesis of TiO 2 by hydrothermal method
The slight modifications were made on the synthesis of TiO 2 NPs from the previously reported literature [ 36 ]. Initially, 0.1 N of titanium tetra isopropoxide is dissolved in 20 ml of ethanol solution under continuous stirring for 30 min. After that, add a few drops of distilled water to form the dispersion medium. The product was placed on the ultrasonic bath for 20 min. After sonication, the solution was transferred into an autoclave at 150 °C for 3 h. Then the solution was cool to room temperature, and it was washed and centrifuged with deionized water to remove the impurities. Then it is filtered with Whatman No. 1 Filter paper. The filtered sample was dried oven at 110 °C for 5 h, and it is further annealed at 500 °C for 2 h. The resultant TiO 2 NPs was collected and processed with further characterization.
2.3 Green synthesis of TiO 2 nanoparticles using jasmine flower extract
TiO 2 NPs were synthesized using the facile green synthesis route from Jasmine flower extract acts as a reducing/capping agent. The jasmine flowers were purchased from the local market of Nagercoil, Tamilnadu. The jasmine flower extract was prepared by adding 50 g of jasmine flower in 100 ml distilled water and boiled the mixture with a hotplate for 30 min. Then the aqueous solution has been filtered and stored for further tests. Take 50 ml of titanium tetra isopropoxide (TTIP) in a 100 ml beaker and add 20 ml of flower extract drop by drop to the above TTIP solution. The solution was stirred by 3 h at room temperature. The colour of the solution was changed from pure white to yellowish-grey. A change of colour confirms the formation of titanium dioxide nanoparticles. After that, the solution was Filter and dried at 110 °C for 5 h. Then the dried samples were calcined Muffle furnace at 500 °C for 2 h [ 37 , 38 ].
2.4 Characterization of TiO 2 nanoparticles
X-Ray Diffraction pattern of investigated titanium dioxide nanoparticles was recorded by using PANanalytical XPERT PRO Diffractometer. FT-IR spectrum was recorded by using the Perkin Elmer spectrophotometer recorded from 400 to 4000 cm −1 . The Surface morphology of TiO 2 nanoparticles was visualized using SEM. EDS spectrum is used to determine its homogeneity and its elemental distribution of elements in the investigated compound. SEM with EDS spectrum was recorded with the help of Quanta FEG-250. UV–Visible Diffuse Reflectance Spectrophotometer (DRS) spectrum was recorded using a Shimadzu 2700 spectrophotometer. The reflectance spectrum was recorded in the range of 200–800 nm. The antibacterial activity of TiO 2 nanoparticles was studied for both gram-positive and gram-negative bacteria by the disk diffusion method.
2.5 Antibacterial activity
The antibacterial activity of titanium dioxide nanoparticles was tested by the agar diffusion method. First, the nutrient agar was uniformly spread in the Petri dish plate. Then fix the 6 mm diameter well, which is used to study the inhibition zone. Place 50 μl of TiO 2 NPs in 6 mm diameter well. The culture medium was incubated at 37 °C C for 24 h under aerobic conditions. The zone of inhibition layer was measured using the millimeter region. The Zone of inhibition results in the antibacterial activity of TiO 2 NPs.
2.6 Photodegradation of Methylene blue
Methylene blue dye is used as a model pollutant for photodegradation. Take 100 mg of TiO 2 NPs in 250 ml beaker with contains 100 ml methylene blue solution under ultrasonication for 20 min. Furthermore, the mixed solution was kept in a chamber at the dark condition to attain the absorption desorption equilibrium. The photodegradation of methylene blue dye was recorded with the help of UV–Visible irradiation at every 30 min regular interval from 0 to 120 min. The absorbance of methylene blue dye was recorded using 200 µl volume and 10 cm length quartz cuvette. Then the dye degradation efficiency was calculated.
3 Results and discussion
3.1 x-ray diffraction.
The X-ray diffraction technique analyzed the crystalline phase, crystal structure, purity, and average crystalline size of the TiO 2 NPs. Figure 1 displays the XRD pattern of bio mediated and chemically synthesized TiO 2 NPs. The diffraction angle (2ϴ) at 27.45°,36.75°,41.27°, 44.07°, 54.27°, 56.54°, 62.78°, 64.05°, 69.01°, and 69.85° which corresponds to the Braggs reflection plane of (110), (101), (111), (210), (211), (220), (002), and (301) respectively. The observed angle at 27.45° (101) represents the high crystalline nature of TiO 2 NPs. The XRD pattern of TiO 2 NPs shows good agreement with the JCPDS card number: 89-4920, and it exhibits the tetragonal crystal structure [ 39 ]. The average crystalline size of TiO 2 NPs was calculated from the XRD pattern using the Debye Scherer formula
where D is an average crystalline size, K is a dimensionless shape factor with a value close to unity, λ is the wavelength of the X-ray, β is the full width half the maximum intensity (FWHM) and θ is the Bragg angle [ 40 , 41 ]. The average crystalline size of TiO 2 NPs was found in the range of 31–42 nm. Observed average crystalline size values well-matched with previous reports [ 42 , 43 , 44 ]. However, there is a small difference in peak strength, phase shift, and average crystalline size due to the synthesis process. The green TiO 2 nanoparticles were exhibited higher intensity TiO 2 peaks due to the presence of polyphenolic compounds in the plant extract. XRD data were tabulated in Table 1 .
Shows XRD pattern of TiO 2 nanoparticles
3.2 Fourier transform infrared spectroscopy
The functional group and chemical compound present in the prepared TiO 2 NPs were identified using the FT–IR spectrum. Figure 2 shows the FT–IR spectrum of TiO 2 NPs. The broadband at 3709–3712 cm −1 correlates to the O–H Stretching vibration [ 45 , 46 ]. The band around 1513–1516 cm −1 reflects the bending vibration of functional groups C–H [ 47 ]. The thin band at 1269–1278 cm −1 displays the alcohol functional groups [ 48 ]. The band assigned at 1057–1055 cm −1 corresponds to C–O groups of aromatic stretching vibration. The strong band at 460 cm −1 and 900 cm −1 reveals the formation of Ti–O and Ti–O-Ti bending vibrations, respectively [ 49 ]. Peaks observed at 460–1000 cm −1 may disappear/partially decrease in intensity by annealing temperature [ 50 ]. The metal oxide bonds like Ti–O–Ti and Ti–O confirms the existence of TiO 2 in the prepared TiO 2 NPs. The presence of the Ti–O–Ti bond is due to the strong interaction (capped) of biomolecules with TiO 2 NPs which results in the presence of alkaloids, coumarins, flavonoids, tannins, and terpenoids [ 51 ]. These phytochemicals are responsible for reducing the bulk of titanium dioxide to stable TiO 2 in green synthesis [ 39 ]. The hydroxyl groups present at 3709–3712 cm −1 in TiO 2 NPs, which enhances the photocatalytic performance. The IR frequency of green synthesized TiO 2 NPs are slightly changed compared to chemically prepared TiO 2 NPs. The Band assignment corresponds to tentative frequency was tabulated in Table 2 .
Shows FT–IR spectra of TiO 2 nanoparticles
3.3 UV–Visible spectroscopy
The optical behavior of the TiO 2 NPs was investigated using the DRS spectrum. The UV–Visible reflectance spectrum of TiO 2 NPs was shown in Fig. 3 . The spectra of TiO 2 NPs at 385 nm indicate the charge coordinated electronic transition between the O 2p state and Ti at 3d state [ 52 ]. During the biosynthesis process, the colloidal solution turns from white to yellowish-grey, which indicates the formation of titanium dioxide nanoparticles. The white colour dispersion shows the formation of TiO 2 NPs during the chemical process. The sharp absorption peak corresponds to the change in the crystalline phase and the average crystalline size [ 53 ]. Hence the investigated nanomaterial is applicable for catalytic application [ 54 , 55 ]. The sharp absorbance peak around 385–400 nm region confirms the formation of TiO 2 NPs. The reflectance spectra of TiO 2 NPs were well matched with the previous reports [ 56 ].
Shows UV–Visible reflectance spectrum of TiO 2 nanoparticles
3.4 Scanning electron microscope
Figure 4 a, b, c, d shows the SEM images of prepared TiO 2 NPs. The SEM image of bio-mediated TiO 2 nanoparticles is a spherical shaped structure and the chemical synthesis TiO 2 nanoparticles sphere-like surface morphology. The average particle size of a spherical shaped TiO 2 NPs was found in the range of 32–48 nm. The Particle size obtained from SEM results is well correlated with the average crystalline size from XRD. In general, the decrease in particle size is inversely proportional to the surface volume of the material. Therefore the lower particle size material quickly penetrates the toxic elements as well as the bacterial surface that led the process of decomposition [ 57 , 58 ].
Shows SEM images of TiO 2 nanoparticles at various magnification a and b Green synthesis method c and d Chemical method
3.5 Elemental dispersive spectrum
The elemental analysis of the chemical compounds was investigated through EDS spectra. Figure 5 shows the EDS spectra of Bio-mediated TiO 2 NPs. The elements present in the synthesized TiO 2 NPs are Titanium (Ti), and Oxygen (O) [ 59 ]. In bio-mediated TiO 2 NPs, the composition of the titanium element is high compared to oxygen content. The atomic and weight percentage of the TiO 2 NPs are tabulated in Table 3 .
Shows EDS spectra of TiO 2 NPs (green synthesis)
3.6 Anti-bacterial activity
The antibacterial study of TiO 2 nanoparticles was examined by gram-positive and gram-negative bacteria. Figure 6 a, b shows anti bacterial activity of titanium dioxide nanoparticles. The cell wall of the gram-negative bacteria is composed of thin peptidoglycan and a thick layer of peptidoglycan in gram-positive bacteria. The zone inhibition layer of the TiO 2 NPs was examined against Escherichia coli , Staphylococcus aureus , and Klebsiella pneumoniae , which is measured in mm scale. Microbial pathogens may causes multiple diseases to living species. The zone inhibition layer for gram-negative bacteria such as E-Coli and Klebsiella are 12 and 11 mm for chemical synthesis and, 14 and 12 mm for green synthesis, respectively. At the same time, the zone inhibition layer for gram-positive microbial pathogens like staphylococcus aureus is 8 and 7 mm for green and chemical synthesis process. The high zone inhibition layer was observed in green synthesized TiO 2 NPs. The zone inhibition layer of pathogenic bacteria Escherichia coli and Klebsiella pneumonia have strong outcomes relative to Staphylococcus aureus . Thin walls of gram-negative bacteria are quickly broken by a positive ion of TiO 2 NPs. The Electrostatic interaction exists between the positive TiO 2 NPs and the negatively charged cell wall surface of E.coli and Klebsiella pneumoniae bacteria which leads to a high inhibition region on gram-negative bacteria. Bacterial cell walls induced by reactive oxygen species (ROS), such as hydroxyl group and superoxide result in a rupture on the bacterial cell wall. As the surface area of nanoparticles increases, there is an increase in surface oxide ion concentration and resulted in more effective destruction of the cytoplasm membrane and the cell wall of bacteria [ 60 ].
In this present report, gram-negative bacteria are highly potent when compared with gram-positive bacteria. The difference in diameter of zone of inhibition is due to the difference in susceptibility of bacteria, the morphology of nanoparticles, phase formations, particle size, shape, and synthesis method. The effect of inhibition of growth on both positive and negative bacteria owing to its vigorous antibacterial activity [ 61 , 62 ]. The zone of inhibition (ZOI) of prepared TiO 2 NPs shows an excellent antibacterial activity. Thus, the prepared TiO 2 NPs are highly applicable to biomedical applications. The efficient antimicrobial agents must be poisonous to pathogens with the capability to be covered as antimicrobial coverings on medical appliances, purity testing devices, wound dressings, textiles, biomaterials, consumer products, food packaging [ 63 ].
3.7 Photocatalytic activity
The photodegradation of methylene blue dye was studied with the help of UV–Visible irradiation technique. Figure 7 a, b shows the schematic representation of the photodegradation of methylene blue. The Photodegradation efficiency of TiO 2 NPs was calculated using the following equation.
where C t is the temporal concentration of MB at time t and C 0 is the initial concentration of MB [ 64 ].
Shows anti-bacterial activity of TiO 2 nanoparticles a Green synthesis method, b chemical method
Photocatalytic activity of chemically and bio-mediated TiO 2 NPs were examined by methylene blue. In this study, methylene blue dye is used as a pollutant because it is widely utilized in the textile industry for colouring purposes, and also it is more harmful to human beings. So, the removal of methylene blue from wastewater is a challenging problem [ 65 ]. The photodegradation efficiency and the absorption spectra of methylene blue dye with a regular interval of time, as shown in Fig. 7 a, b. The UV absorption spectra of methylene blue at 665 nm corresponds to π–π* transition. Absorption peak intensity reduction results indicate the degradation of methylene blue. The Biologically synthesized TiO 2 NPs have higher degradation efficiency compared to chemically synthesized TiO 2 NPs. The degradation efficiency increases due to the presence of the hydroxyl group in jasmine flower extract. Bio mediated TiO 2 NPs results in the maximum degradation of 89% under 120 min of irradiation. When TiO 2 NPs undergo UV–Visible irradiation, the electron–hole pair is generated. The positive holes of TiO 2 NPs break water molecules to form hydrogen gas/free radical and negative electron react with oxygen molecules to form superoxide anions [ 66 ]. The electron–hole pair results in the formation of a hydroxyl group (OH · ) and superoxide’s (O 2 ·− ). These superoxide’s and hydroxyl groups are responsible for the degradation of methylene blue [ 67 ]. During the reduction process, methylene blue is converted to Leuco methylene blue (LMB) [ 68 ]. The degradation efficiency of bio-mediated TiO 2 and chemically investigated TiO 2 NPs are 89% and 82% respectively.
Shows photocatalytic activity of TiO 2 NPs Green synthesis method, and chemical synthesis method
4 Conclusion
In this present work, TiO 2 NPs are successfully synthesized by green synthesis and hydrothermal method (chemical method). Colour changes confirmed the reduction of bulk Titanium to nanoparticles. The photodegradation of methylene blue under UV–Visible irradiation results in the degradation of methylene blue to leuco methylene blue. Bio-mediated TiO 2 shows maximum degradation efficiency of 89% under 120 min of irradiation. SEM image reveals that a uniform spherical shape surface morphology. The antibacterial activity of TiO 2 NPs was visualized by the agar diffusion method. Antibacterial activity of TiO 2 NPs was tested against bacterial pathogens such as Staphylococcus aureus (gram-positive bacteria) Escherichia coli and Klebsiella pneumonia (gram-negative bacteria). The bio-mediated TiO 2 NPs exhibit a good potent on antibacterial activity. The suggested results have inferred the property of TiO 2 nanoparticles is suited for biomedical and wastewater treatment (dye degradation) applications.
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Aravind, M., Amalanathan, M. & Mary, M.S.M. Synthesis of TiO 2 nanoparticles by chemical and green synthesis methods and their multifaceted properties. SN Appl. Sci. 3 , 409 (2021). https://doi.org/10.1007/s42452-021-04281-5
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Green synthesis of silver nanoparticles using carob leaf extract: Characterization and analysis of toxic effects in model organism Galleria mellonella L. (The greater wax moth)
Affiliations.
- 1 Department of Bioengineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana, Turkey.
- 2 Department of Biology, Faculty of Science and Letter, Cukurova University, Adana, Turkey.
- 3 Department of Bioengineering, Faculty of Engineering, Adana Alparslan Turkes Science and Technology University, Adana, Turkey. [email protected].
- PMID: 39294535
- DOI: 10.1007/s11356-024-34996-y
Silver nanoparticles (Ag NPs) have been used in many studies due to their inhibitory properties on microorganisms such as bacteria and viruses. In recent years, due to global problems such as environmental pollution, the green synthesis (biosynthesis) method is frequently preferred because it is simple and low cost and does not require the use of toxic substances. The aim of this study is to synthesize silver nanoparticles (Ag NPs) from Ceratonia siliqua L. leaves and investigate their antioxidant and immunotoxic properties using Galleria mellonella last instar larvae. The UV spectrophotometer, TEM, XRD and FTIR measurements were used to characterize the Ag NPs. In this study, it was determined that the effects on antioxidant enzyme activities (SOD, CAT, GPx, GST), acetylcholinesterase (AChE) and total hemocyte count (THC) as well as phenoloxidase activity determine their effect on antioxidant defence and the immune system in model organism G. mellonella larvae. We observed that green synthesized Ag NPs accumulate in the midgut of the larvae and led to the increasing of CAT and SOD activities. GST and AChE activities were increased in the fat body of the larvae; otherwise, it was decreased in the midgut. Moreover, increases were found in THC and phenoloxidase activity. Consequently, green synthesized silver nanoparticles led to oxidative stress and immunotoxic effects on G. mellonella larvae.
Keywords: Antioxidant activity; Carob; Green synthesis; Immunotoxicity; Silver nanoparticles.
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- Abdelwahab GM, Mira A, Cheng YB, Abdelaziz TA, Lahloub MFI, Khalil AT (2021) Acetylcholine esterase inhibitory activity of green synthesized nanosilver by naphthopyrones isolated from marine-derived Aspergillus niger. PLoS ONE 16(9):e0257071. https://doi.org/10.1371/journal.pone.0257071 - DOI
- Ajlouni AW, Hamdan EH, Alshalawi RAE, Shaik MR, Khan M, Kuniyil M, Alwarthan A, Ansari MA, Khan M, Alkhathlan HZ, Shaik JP, Adil SF (2023) Green synthesis of silver nanoparticles using aerial part extract of the anthemis pseudocotulaboiss. Plant and their biological activity. Molecules 28(1):246
- Aksu Demirezen D, Yılmaz Ş, Demirezen Yılmaz D, Yıldız Y (2022) Green synthesis of iron oxide nanoparticles using Ceratonia siliqua L. aqueous extract: improvement of colloidal stability by optimizing synthesis parameters, and evaluation of antibacterial activity against Gram-positive and Gram-negative bacteria. International J Mater Res 113(10):849–861 - DOI
- Akter M, Sikder MT, Rahman MM, Ullah AKMA, Hossain KFB, Banik S, Hosokawa T, Saito T, Kurasaki M (2018) A systematic review on silver nanoparticles- induced cytotoxicity: physicochemical properties and perspectives. J Adv Res 9:1–16 - DOI
- Annu, Ahmeda S, Kaurb G, Sharmac P, Singhc S, Ikrama S (2018) Fruit waste (peel) as bio-reductant to synthesize silver nanoparticles with antimicrobial, antioxidant and cytotoxic activities. J Appl Biomed 175:1–11
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Eco-Friendly Greener Synthesis of Nanoparticles
The exploitation of naturally obtained resources like biopolymers, plant-based extracts, microorganisms etc., offers numerous advantages of environment-friendliness and biocompatibility for various medicinal and pharmaceutical applications, whereas hazardous chemicals are not utilized for production protocol. Plant extracts based synthetic procedures have drawn consideration over conventional methods like physical and chemical procedures to synthesize nanomaterials. Greener synthesis of nanomaterials has become an area of interest because of numerous advantages such as non-hazardous, economical, and feasible methods with variety of applications in biomedicine, nanotechnology and nano-optoelectronics, etc.
Introduction
In the current scenario of drug delivery, nanosystems like nanoparticles (NPs), liposomes, dendrimers, solid lipid NPs and others are being employed for a controlled, sustained and targeted delivery of active pharmaceutical entities. All of these nanomaterials have various advantages and patient-friendly because of reduction in dose frequency and much better retention time of drugs within the targeted site compared to conventional dosage forms. The primary aim of these nanosystems is to sustain the therapeutic amount of drug within the bloodstream for a longer time period. But still, there are some important factors that affect the delivery of drugs as the drug carrier, targeted site for delivery of drugs, drug administration route and the tactic considered to boost therapeutic efficiency of medication. These factors reduce the undesirable effects of the active pharmaceutical entity and improved the therapeutic performance of drugs. 1 Although UV irradiation, aerosol technologies, lithography, laser ablation, ultrasonic fields, and photochemical reduction techniques have been used successfully to produce NPs, they remain expensive and involve the use of hazardous chemicals, which leads to major attention toward the expansion of eco-friendly and sustainable greener synthesis of NPs. 2 Nano-biotechnology is a newer term formed through merging of three different fields i.e. nanotechnology, microbiology and biotechnology as microbes are being used for synthesis of nanomaterials through biotechnological methods. Bioremediation and bioleaching bio-mineralization have been performed through metal–microbe interactions, but nano-biotechnology is at its early stage period. In spite of their potent outcomes, it carries an encouraging application in drug delivery through nano-methods. This review article highlights the green synthesis of NPs from various sources such as plants, polysaccharides and microbes with their applications in different areas. 3
Why green methods for synthesis of nanoparticles?
Currently, there are numerous chemical and physical methods available in the literature for production of nanomaterials, which deliver a higher rate of production and well-controlled size and shape of nanomaterials but these approaches are discouraging due to higher loss of energy and capital, use of noxious chemicals, and production of large amount of bio-waste. These key factors influence the commercial level scale-up process of nanomaterials economically as well as environmentally. Additionally, the clinical use of nanomaterials prepared through chemical methods has been limited due to issues of biocompatibility, toxicity and stability. These components elevates requirement of eco-friendly, cheaper and biocompatible methods for production of nanomaterials. In comparison to conventional physical and chemical methods, greener route for NPs synthesis offers economical, environment-friendly and nontoxic approaches ( Figure 1 ). 3
Different properties of nanoparticles.
Nanoparticles synthesis from plants and their extracts
Due to environment friendly behavior, lower toxicity, cheap, more biocompatibility and better size controlling aspects offered a higher prominence for the production of nanomaterials through greener ways over physical and chemical methods. The primary goal of nanotechnology is to develop a reliable and better production method, which regulates the chemical composition, morphology and better monodispersing systems in large scale production of nanomaterials. Numerous eco-friendly methods for synthesis of NPs systems from plants, bacteria, and fungi have been recommended in literature because of their economical, low toxicity profile and biocompatible in nature. Jayprakash et al, prepared silver NPs (AgNPs) with Tamarindus indica natural fruit extract through microwave-assisted greener synthesis. The plant-based extract was acted as a reducing as well as capping mediator for AgNPs synthesis. Morphological characterization of NPs was performed using different techniques such as X-ray diffraction (XRD), high-resolution scanning electron microscopy and transmission electron microscopy. The average particle size of prepared NPs was found to be 6-8 nm and XRD studies revealed the face-centered cubic silver presence. Good antibacterial action was exhibited by the prepared silver NPs through a simplistic, economical and greener method. AgNPs production methods using plant extracts are reported in literature like Mangifera indica leaf, Murraya koenigii leaf, Jatropha curcas , Mangosteen leaf, Cinnamomum zeylanicum leaf, Aloe vera , Camellia sinensis , honey and mushroom. Fruit extracts were also being utilized for NPs preparation such as lemon, pear, papaya, goose berry and tansy etc. NPs prepared through consuming fruit or plant extracts offer an advantage of non-aggregation of NPs over long term storage conditions. 4
Aloe vera plant extract was used for the synthesis of spinal shaped polycrystalline nanopowders of Ni x Cu 0.25 Zn 0.75–x Fe 2 O 4 (where x = 0.25, 0.35, 0.5) having an average particle size of 15-40 nm via simple solution method consuming metallic nitrates and Aloe vera plant extract mixture. Ferromagnetic activities were exhibited from obtained nanomaterials. 5 Coffee and tea extracts had been exploited for synthesis of stable NPs of noble metals (i.e. Pd and Ag) in the size range of 20-60 nm. These stated approaches might be employed for NPs production of other noble metals like Pt and Au. 6 Oxides of various metals had been utilized for nanoparticle production like titanium oxide. Nyctanthes leaf extract and titanium isopropoxide solution were used for obtaining titanium (IV) oxide nanoparticle having average size (100–150 nm). 7 Aqueous extracts of the manna of Hedysarum plant and the soap-root ( Acanthophyllum bracteatum ) plant were exploited to prepare the NPs and an average diameter of the prepared NPs in solution was about 29–68 nm ( Table 1 ). 8
| | | |
plant | Aqueous extracts of the manna of plant and the soap-root | Silver Nanoparticles | Antibacterial activity |
Miller | Leaf extract | Zinc oxide NPs | Antimicrobial, and dermatologic application |
| Leaf extract | Zinc oxide NPs | Photocatalytic activity |
| | Zinc oxide nanoparticle | Antioxidant activity, photocatalytic activity |
Honey | | Zinc oxide nanopowder | Cytotoxicity effects |
Mill. | Leaf extract | Silver and gold NPs | Antimicrobial activity |
Lam. | Fruit extract | Gold NPs | Antimicrobial activity |
| | Silver and gold NPs | Antimicrobial activity |
| Flower | Gold NPs | Antimicrobial activity |
| Bark extract | Gold NPs | Catalytic reducing agent |
| Aqueous leaf extract | Silver and gold NPs | |
| Leaves | Silver NPs | Biolarvicidal |
| Leaves | Palladium NPs | Catalytic activity in dye degradation |
Banana | Peel | Cadmium sulphide | |
Red ginseng | Root | Silver NPs | Antibacterial |
| Leaves | Lead NPs | Antibacterial and photo- catalytic activity |
| Fruits | Copper NPs | Antimicrobial |
| Leaves | Silver NPs | Antibacterial |
Nanoparticles synthesis from natural polysaccharides
In spite of plant parts extracts polysaccharides are also being employed for nanomaterials preparation as an eco-friendly approach. Sulfated polysaccharides obtained from marine red algae ( Porphyra vietnamensis ) were utilized for silver NPs synthesis. The particle size of prepared nanoparticle was found to be about 13 ± 3 nm and surface plasmon resonance centred at 404 nm. The spectroscopic study revealed the connection of reduction of silver nitrate by sulfate moiety of obtained polysaccharide. 26 The Greener method for preparation of silver NPs was employed by dissolving silver (III) ion-containing rice wine and soda over-temperature raging (25-55°C) at pH 6.5 without using extra protective material. In this technique, rice wine played dual role as solvent and reducing agent while soda was utilized as base catalyst and protective agent. The obtained mixture exhibited higher stability and negligible precipitation even after long term storage for months. 27
In another study, Chen et al proposed deformable liposome of flurbiprofen coated with chitosan for ocular drug delivery to improve the transcorneal absorption and enhanced the pre-corneal drug residence time. These liposomes were formulated through the modified ethanol injection technique and then chitosan was coated over them. Gamma scintigraphy technique was employed to check the pre-corneal retention period and draining out dynamics of drug in-vivo . The deformable liposome of flurbiprofen coated with chitosan prolonged the area under the remaining activity-time up to 2.84 and 1.53-fold compare to flurbiprofen solution and deformable liposome of flurbiprofen respectively. No ocular injury or irritation was reported with use of deformable liposome of flurbiprofen coated with chitosan in-vivo . 28 Curcumin, N,O-carboxymethyl chitosan and oxidized alginate-based in situ injectable nanocomposite hydrogel formulation showed a novel dermal wound dressing application. The development of nanocomposite of curcumin involved incorporation of methoxy poly(ethylene glycol)-β-poly(-caprolactone) copolymer into N,O-carboxymethyl chitosan and oxidized alginate hydrogels system. Prepared hydrogels were injected on rat dorsal injuries to study the healing process. The study revealed the considerable improvement in epidermal re-epithelialization and deposition of collagen within the tissue of wound. 29 In 2012, Tian et al, prepared glycyrrhetinic acid and modified sulfated chitosan-based drug carrier system for anticancer activity. The prepared drug-carrying nanosystem was found to be spherical in shape and around 200 nm in size, showing a significant anticancer activity. 30 Among the various biological NPs, those produced by medicinal plants have been found to be the most pharmacologically active, possibly due to the attachment of several pharmacologically active residues ( Table 2 ).
| | | |
Alginate | Isoniazid and pyrazinamide | NPs | Anti-tubercular activity |
Alginate–oligochitosan–Eudragit L100-55 | Naproxen | Microparticles | Non-steroidal anti-inflammatory activity |
Sodium Alginate | Isoniazid | Microspheres | Anti-tubercular activity |
Chitosan | Zinc sulphide and mannose | Nanoprobes | Targeted cancer imaging |
Galactosylated chitosan | Doxorubicin | Microbubbles | Anticancer activity |
Chitosan | Prednisolone | NPs | Renal targeting drug delivery |
Lauryl succinyl chitosan | Human insulin | Micro/nano-particles | Oral peptide delivery system |
Hyaluronic acid | Tacrolimus | Niosomes | Ocular drug delivery |
Alginate | Cisplatin and doxorubicin | Liposome | Anticancer drug delivery |
Chitosan | Artemisinin | Magnetic NPs | Drug delivery in breast cancer cell |
Chitosan | IR820- iron oxide | Magnetic nanosystem | Imaging agent against melanoma |
Gelatine | Dextran sulphate | NPs | Expression of MUC5AC in ocular surface epithelial cells |
Gum cordia | Fluconazole | NPs | - |
Cationized gelatine | Dextran sulphate and chondroitin sulphate | NPs | Ophthalmic drug delivery |
Nanoparticles synthesis from microbial origin
Plant-based extracts and microbial cultures have been used for the greener or eco-friendly synthesis of NPs all over the world. Due to quick growth rate, low-cost cultivation and capability of survival in ambient environmental conditions like temperature, pressure and pH make microbes a favorable candidate for NPs synthesis. These have inherent potential to prepare NPs of inorganic materials via reduction mechanism through intracellular and extracellular routes because of their survival capability in the metallic noxious surroundings. Metallic ions present in the environment are trapped by microbes and with the help of enzymatic activity and microbes convert these ions into their elemental forms. 3
Fungi based greener synthesis of nanomaterials is attaining much popularity worldwide. 45 In comparison to bacteria, higher yield of NPs is obtained using fungal strains, because of larger biomass. NPs with different shapes and sizes were prepared by using numerous fungal species such as Fusarium oxysporum , Verticillium luteoalbum , Trichothecium sp., Colletotrichum sp., Alternata alternate, Aspergillus oryzae , Trichoderma viride, etc. 46 Largely, the use of toxic or hazardous chemicals can be eliminated for production of biologically and pharmaceutically important materials by the use of eco-friendly greener chemicals and microorganisms. Numerous reports have been published for greener synthesis of metal oxide NPs (like manganese oxide, copper oxide, iron oxide, titania) with the use of microorganism’s cultures like Lactobacillus sp., Yeast cells, Fusarium oxysporum, Shewanella oneidensis, Saccharomyces cerevisiae and Bacillus sp. cells etc. 45 Metallic ions felt great reduction effect over them due to bacteria leads to synthesize NPs. Research studies revealed the bacterial based reduction mechanism over metallic ions leads to precipitation of metals to nanometres scale. Fungal species had different enzymes (intracellular and extracellular) which could produce a well-defined size and shaped mono-dispersed NPs. 46
In a study, Malarkodi et al, biosynthesized NPs of titanium dioxide using Planomicrobium sp. and their anti-microbial activities were estimated against K. planticola , Bacillus Subtilis and Asper niger . 47 NPs of iron were prepared using Fusarium oxysporum presenting antimicrobial activity against Escherichia coli, Staphylococcus sp. and Bacillus . The respiration mechanism of microbes depends on concentration of substrates, was restricted by these iron NPs via limiting the oxygen supply. 48 The concentration of substrates, pH and temperature of the incubated medium influenced the growth, mono-dispersion and dimensions of the formulated NPs. 49 In a similar study, Sharma et al revealed that the capping agent and incubation time period directly influenced the stability and size of formulated NPs, respectively. 50 Synergistic action of different antibiotics viz. nitrofurantoin, ciprofloxacin and carbenicillin with silver NPs prepared via eco-friendly method from R. stolonifer were exhibited against ESBL-strains of Enterobacteriaceae . Both ciprofloxacin and Carbenicillin exhibited increment of 30.53% and 33.56% respectively, while around 50% of increment was reported with nitrofurantoin. 51 In the similar fashion, combination of silver NPs prepared from Brevibacterium frigoritolerans with various antibiotics (like penicillin G, novobiocin, oleandomycin, vancomycin, rifampicin) improved the antimicrobial effect of these antibiotics especially against pathogenic strains of Bacillus cereus, Escherichia coli, Salmonella enterica, Vibrio parahaemolyticus, Candida albicans and Bacillus anthracis . 52
Breast cancer malevolence is one of the major causes of death among women. According to the reports described in literature, these microbes based metallic NPs are offering significant anticancer activity. Platinum NPs biosynthesized from Saccharomyces boulardii tested against A-431 and MCF-7 cell lines exhibiting anticancer activity. 53 Silver NPs prepared using Cryptococcus laurentii present a better anticancer effect against cancerous cell line especially breast cancer cell lines. The stimulation of apoptosis, sustainability and endocytic action of tumor cell lines were affected by greener synthesized silver NPs. The endocytic activity of tumour cell was found to be equivalent to efficiency of silver NPs. 54 Selenium is trace element with anticancer activities and Streptomyces bikiniensis was utilized to biological preparation of selenium nanorods exhibiting antitumor activity against MCF-7 and Hep-G2 cancer cells. Deployment of copper bound to chromatin trailed by pro-oxidant effect leads to decrease Hep-G2 and MCF-7 cells and this was the mechanism of action that followed by these nanorods. 55 In vitro anticancer activity against breast cancer and human liver cells viz. MCF-7 and HEPG-2, respectively, were conducted with gold NPs synthesized from Streptomyces cyaneus revealing stimulation of mitochondrial apoptosis and cytokinesis detention lead to DNA impairment. 56 Gold NPs synthesized with Candida albicans were estimated to analyze the cancer cells of liver through attachment of NPs with surface-specific antibodies of liver cancer cell. These NPs bounded antibody attached clearly with superficial antigen of affected cell and could recognizably differentiate cancer cell from normal cells. 57 The use of microbially synthesized nanomaterial in diagnostics is at its initial stages and further research in this area would provide more feasible perspective for future.
Fungal species Fusarium oxysporum released a bioactive material via silver nitrate reduction extracellularly. An admirable anti-inflammatory and antibacterial activity are unveiled by silver NPs helps in improvement of wounds healing process. The fungal culture released protein which help in stabilization of silver NPs and nitrate dependent reductase enzyme and quinine shuttle reduce the metallic ions. The antibacterial action of silver NPs prepared by the above-discussed method was evaluated on silk and cotton cloths against S. aureus . 58 Similarly, algae released their protein which not only reduce the silver ions, but also the NPs and thus stabilized the silver NPs. The protein released by Chlorella vulgaris played a double role through reduction of silver ions as well as controlling the synthesis and morphology of NPs. The -OH and -COOH groups present in tyrosine and Asp/Glu residues helped in reduction process of silver ions. The metabolites of marine algae-like Chaetoceros calcitrans, Chlorella salina, Isochrysis galbana and Tetraselmis gracilis reduced the silver ions and thereby synthesized the Silver NPs ( Table 3 ). 59
| | | |
| Silver | 100 nm | Spherical |
| Silver | 10-25 nm | Spherical |
| Silver | 10-50 nm | Spherical |
| Silver | 15-50 nm | Spherical |
| Silver | <100 nm | Spherical |
| Gold | <50 nm | Spherical |
| Silver | 3-5 nm | Irregular |
| Silver | <50 nm | Spherical |
| Gold | <25 nm | Cubic |
| Gold | <6 µm | Octahedral |
| Gold | 30 nm | Irregular |
| Gold | <15 nm | Spherical |
| Platinum | 5 nm | Irregular |
| Hg | <5 nm | Spherical |
| Alloy of silver and gold | <15 nm | Spherical |
| Palladium | <50 nm | Spherical |
| Gold | <15 nm | Triangle |
| Gold | <100 nm | Irregular |
| Gold | <100 nm | Irregular |
| CdTe | 2-4 nm | Spherical |
| BaTiO | <100 nm | Tetragonal |
HSMV-1 | Fe O | <100 nm | Bullet shaped |
| Fe O | <50 nm | Rectangular |
| BaTiO | <5 nm | Spherical |
Yeast | FePO | <100 nm | Nanopowder |
| TiO | <15 nm | Spherical |
sp. | TiO | <35 nm | Spherical |
| ZnO | 55-75 nm | Spherical |
| ZrO | 3-11 nm | Spherical |
| CdS | <20 nm | Spherical |
| CdS | <10 nm | Hexagonal |
| CdS | <10 nm | Cubic |
| PbS | <10 nm | Spherical |
| ZnS | <5 nm | Bio-Film |
Prokaryotes | Fe S | <100 nm | Irregular |
Enzyme-mediated and protein-mediated synthesis of nanoparticles
Biological systems could be used for greener synthesis of NPs in terms of their unique shapes and sizes in a controlled manner. Rangnekar et al prepared gold NPs by using pure α-amylase. In the similar fashion, EcoRI, an endonuclease having free cysteine, reduces the gold ions, while other enzymes were unable to reduce the chloroauric acid to gold NPs without free cysteine exposure. 93 In another study, Roy et al investigated the capacity of cysteine as a reducing agent in spite of the role of cysteine as a capping material on gold NPs. Various analytical techniques were utilized to investigate the linkage of cysteine with gold NPs like ultra-violet visible spectrophotometry, Fourier transform infrared spectroscopy, XRD and Raman spectroscopy. 94 Sharma et al carried out a study of gold and gold: platinum NPs synthesis by using urease enzyme as reducing agent. They investigated the role of cysteine in NPs formation. They modified the cysteine in urease by its reaction with 5,5′–dithiobis in non-denaturation conditions. Due to this modification, there was no NPs formation occurred. Patela et al prepared Glycine max’ (soybean) leaf extract mediated palladium NPs. In this study, the protein present in leaf extract acts as reducing agent for formation of palladium NPs. The possible reaction of tyrosine with palladium ions leads to the donation of electron and conversion of palladium to palladium NPs. 95 Similarly, the glucose oxidase interaction with palladium leads to the formation of palladium NPs. Selenium NPs were produced by using α-amylase from Bacillus methylotrophicus but unfortunately, no mechanism behind the study was discussed ( Table 4 ). 96
| | | |
| Seeds and Leaves | Methanol | Ferric reducing antioxidant activity |
| Leaves | Ethanol | Increased free radical scavenging potential |
| Stem bark | Aqueous | Free radical scavenging activities |
| Leaf gall extracts | Ethanol | Higher content of total phenolics and flavonoids found in the ethanolic extract was directly associated with higher antioxidant activity |
Poly(acrylonitrile-butadiene-styrene) | | Chloroform | Scavenge free radical |
produce Xanthan polymer | Bacteria | | Antioxidant properties |
produce Cellulose polymer | Bacteria | | Reducing power |
produce Curdlan polymer | Bacteria | | Antioxidant properties |
produce Dextran polymer | Bacteria | | Antioxidant properties |
| Seaweed | Aqueous | based alginate polymer exerted moderate antioxidant activity |
Bacterial nanocellulose | Cellulose based membrane loaded with caffeic, ellagic and gallic acids | Aqueous | Higher antioxidant properties |
| Leaf gall extracts | Aqueous and methanol | Enhanced antioxidant properties of methanolic extract comparative to Aqueous extraction. |
Shortcomings in green synthesis of nanoparticles
Though microbes offer a safe, eco-friendly and economically viable approach for synthesis of NPs as compared to their chemical alternates, lack of monodispersing system, uncontrolled size, and time-consuming production process and these disadvantages have limited their use on commercial scale. Owing to nontoxicity of biosynthesized NPs, they showed propitious potential in nanomedicine yet their use in drug delivery and diagnostics is at its infancy. 3 The toxicity of natural polysaccharides could be assessed by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2Htetrazolium (MTS) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, which are currently widely applied since they allow to assess the effect of chitosan NPs onto the cell metabolic activity. 109
De Campos et al assessed the toxicity profile for chitosan via simple colorimetric assay with tryptan blue dye. The study revealed that up to 2 mg/mL of chitosan concentration exhibited no toxicity. The higher concentration of chitosan may be hazardous for survival of cells but, some scientists claimed that acetate buffer solution (pH 6.0) might contributes to the toxicity for cell survival. 110 On the basis of MTT assays, some of the reports considered cytotoxic behavior of chitosan NPs were greater in macrophages than in fibroblasts. The higher concentration of particles caused cells death by modifying the metabolism process of cell via nanoparticle internalization, but not due to membrane degradation. 111
In the case of plants, the charge present over various phytochemicals got changed due to change in pH, which caused the changes in their capability of binding and metallic ions reduction mechanism during synthesis of NPs, affecting the production and morphological characters of NPs. The gold NPs of Avena sativa were prepared in large quantity at pH 3.0-4.0 while a bunch of NPs was observed on pH 2.0. The process of aggregation dominated the reduction mechanism of metallic ions, in case of low pH range. 112
Fungal cultures are extensively being used for the eco-friendly production of nanomaterials. Due to greater quantity of bioactive material secreted by fungi, these were much preferred for large scale production of NPs. 58 But there are some drawbacks regarding fungi-based NPs production as laborious, time-consuming and costly intensive down flowing process, so for commercial-scale production, cheaper and economical method will be needed. While in the case of bacterial based synthesis methods on large scale, the requirements of hazardous chemicals are low but process of bacterial culturing is laborious and control on the nanoparticle’s morphological parameters is less. 46 Organized and meaningful studies are required for understanding some of the mechanisms involving in various reactions to find a more well-defined outcome. There were numerous concepts regarding reduction of Ag + to Ag 0 and the bacteriostatic activity of silver NPs. 2
Finding of study
The study reports found green NPs synthesis as far as physical and chemical methods are concerned to be considered much more effective and environmentally friendly. Due to its diverse characteristics, flexibility, various benefits and applications for humans, NPs are one of the most essential and versatile materials. Green sources are a stabilizing and reducing agent for the synthesis of controlled-size and shape NPs. The application of NPs to crops in general increases agricultural growth and yield. As a constant increase in demand for food, there is a low yield for a staple crop. It is therefore important for sustainable agriculture to market metal oxide NPs. During various processes, such as bioimaging, drug delivery, biosensors and gene delivery, the biomedical applications in this field are being stepped up daily. NPs can serve as intelligent weapons against multiple drug-resistant microorganisms and can replace antibiotics in terms of their toxicity properties. This study is intended to further streamline research in this area on novel analytical and clinical associations.
In summary, here we have discussed various biological or eco-friendly green synthesis of nanomaterials and their biomedical applications. Though, the physical and chemical methods for production of nanomaterials are available currently biological methods are preferred because of their non-hazardous nature as compared to chemical methods. Some of the key factors (like expensive chemicals, higher energy consumption and toxicity) cause the chemically produced nanomaterials unfavorable for use. Thus, a need for biocompatible, greener and economical approaches arises for production of NPs. Plants based extracts, naturally obtained polysaccharides and microbes are the targeted materials for fulfilling the desire of suitable methods for biological production of NPs. But still some numerous concepts are required to be probed in more details like methods for large scale production with cheaper cost and controlled behavior. Detailed investigations regarding controlled morphology, biocompatibility and pharmacokinetic studies are also desirable. So, more research work should be focussed on understanding the concepts and mechanisms involved in biological and economical production of nanosystems using plant sources and microorganisms.
Ethical Issues
Not applicable.
Conflict of Interest
The authors have no conflict of interest.
Acknowledgments
The authors thank the Department of Pharmaceutical Sciences, M.D. University for providing the necessary facilities.
IMAGES
VIDEO
COMMENTS
Nanoparticles are often associated with their small size and numerous applications. However, the synthesis process is equally important as it determines the size and properties of the nanoparticles. While traditional nanoparticle synthesis methods require the use of hazardous chemicals and high-energy consumption, green synthesis offers a sustainable, cost-effective, and environmentally ...
Green synthesis has many advantages compared to chemical and physical methods: it is non-toxic (Devi et al., 2019), pollution-free (Alsammarraie et al., 2018), environmentally-friendly, economical (Kataria and Garg, 2018), and more sustainable (Nasrollahzadeh and Mohammad Sajadi, 2016).However, there are issues in the extraction of raw materials, reaction time, and quality of final products.
Abstract. With the increasing concern over the environmental impact of conventional chemical methods, environmentally friendly processes, commonly known as green chemistry, for the synthesis of nanoparticles have gained growing interest in the field of nanobiotechnology. This review focuses on synthesis of metallic nanoparticles (NPs) based on ...
For the green synthesis of silver nanoparticles, a silver metal ion solution and a reducing biological agent are required. The easiest and least expensive method for producing AgNPs is to reduce and stabilize Ag ions using a mixture of biomolecules, such as polysaccharides, vitamins, amino acids, proteins, phenolics, saponins, alkaloids, and/or ...
Green synthesis methods provide minimal to no harm to the environment, or indeed to the individuals involved in their fabrication, and are equally efficacious as the traditional synthesis methods. It is our belief that nanomaterials will revolutionize our daily lives, and we have seen first-hand the power of nanoparticles with the SARS-CoV-2 ...
We also provide an overview of the biomolecules that were found to be suitable for NP synthesis. This work is meant to be a support for researchers who intend to develop new green approaches for the synthesis of NPs. Keywords: metal nanoparticle, metal oxide nanoparticle, green synthesis, biological method. 1.
In particular, the green synthesis method utilizing plant extracts as reducing, stabilizing, and capping agents in the formation of nanoparticles is an alternative to eliminating the challenges ...
In this review chemical, physical and green synthesis of nanoparticles is reported. The synthesized nanoparticles are synthesized using different qualitative and quantitative techniques. ... Due to simplicity, sol-gel method is the most preferred bottom-up method for the synthesis of nanoparticles. It is the method in which suitable chemical ...
Green approach for synthesis of NPs. Traditional methods are used from past many years but researches have proved that the green methods are more effective for the generation of NPs with the advantage of less chances of failure, low cost and ease of characterization [Citation 6].Physical and chemical approaches of synthesizing NPs have posed several stresses on environment due to their toxic ...
The green synthesis of nanoparticles has gained a lot of attraction since it uses non-toxic phytochemicals and avoids the dangerous ingredients that would otherwise be used in chemical synthesis ...
Green synthesis of nanoparticles involves the use of plant or plant parts for the bioreduction of metal ions into their elemental form in the size range 1-100 nm [2]. The process of green synthesis is more efficient, simpler, and economical, and can easily be scaled up to perform larger operations [8].
Over the last decade, novel synthesis approaches/methods for nanomaterials (such as metal nanoparticles, quantum dots (QDs), carbon nanotubes (CNTs), graphene, and their composites) have been an interesting area in nanoscience and technology [1,2,3,4,5,6,7,8,9].To obtain nanomaterials of desired sizes, shape, and functionalities, two different fundamental principles of synthesis (i.e., top ...
Green synthesis of nanoparticles has been identified as a fallback method as the synthesis process is modest, cost effective, less time consuming, eco-friendly and easy to scale up. This review has discussed about the green synthesis of nanoparticles using plant extracts, microorganisms, fungi, algae and biomolecules.
Green synthesis method, provides a faster metallic nanoparticle production by offering an environmentally friendly, simple, economical and reproducible approach. Given the wide range of ...
Green synthesis of nanoparticles (NPs) using plant materials and microorganisms has evolved as a sustainable alternative to conventional techniques that rely on toxic chemicals. Recently, green-synthesized eco-friendly NPs have attracted interest for their potential use in various biological applications. Several studies have demonstrated that green-synthesized NPs are beneficial in multiple ...
Green synthesis of nanoparticles has many potential applications in environmental and biomedical fields. Green synthesis aims in particular at decreasing the usage of toxic chemicals. For instance, the use of biological materials such as plants is usually safe. Plants also contain reducing and capping agents. Here we present the principles of green chemistry, and we review plant-mediated ...
The methods based on the principle of green synthesis have exhibited large potential in the synthesis of nanoparticles which are used as novel agents in treatment of various ailments. For exploitation of various methods of "Green Synthesis", it is imperative to understand the various underlying principles and mechanisms involved in the process.
Metal nanoparticles have been synthesized using a variety of microorganisms, including bacteria, fungus, and yeast, as well as plants. "Green synthesis" is necessary to prevent the generation of undesirable or dangerous by-products via the build-up of dependable, sustainable, and eco-friendly synthesis techniques.
Creation, exploitation and synthesis are nanotechnology concepts that typically consider materials smaller than 1 mm in dimension [10]. Many different methods, such as physical, chemical and green (biological) techniques, have been used to synthesize nanoparticles [11, 12, 13]. The stabilized nanoparticles are formed by reducing ions through ...
Green synthesis of metal nanoparticles. ... Among various greener methods plant-mediated synthesis has increasingly been used for metallic NPs synthesis. Different parts of plants contain different phytochemicals that act as a reducing and capping agent to obtain NPs of diverse morphology. Overall, the biosynthesized metallic NPs is a good ...
Plant-mediated synthesis of nanoparticles is a green chemistry approach that connects nanotechnology with plants. Novel methods of ideally synthesizing NPs are thus thought that are formed at ambient temperatures, neutral pH, low costs and environmentally friendly fashion. Keeping these goals in view nanomaterials have been synthesized using ...
Green synthesis is a novel method for preparing copper oxide nanoparticles and other nanostructured materials. It provides environmentally friendly approach and promotes sustainability by efficiently using resources, minimizing energy consumption, and producing less waste.
The growth of the environment depends upon developing greener and ecological methods for managing pollutants and contamination from industrial wastewater, which causes significant effects on human health. The removal of these pollutants from wastewater using nanomaterials covers an ecological method that is free from expensive and secondary pollution. In this report, we developed magnetic iron ...
The development of the most reliable and green techniques for nanoparticle synthesis is an emerging step in the area of green nanotechnology. Many conventional approaches used for nanoparticle (NP) synthesis are expensive, deadly, and nonenvironmental. In this new era of nanotechnology, to overcome such concerns, natural sources which work as capping and reducing agents, including bacteria ...
Green synthesis techniques for AgNP present a viable and eco-friendly alternative to conventional methods. In general, environmentally friendly synthesis techniques for synthesizing AgNP have an immense potential for scientific progress and can lead to a wide range of applications.
Green synthesis of Rutin silver nanoparticles- concentration variation method Various concentrations of Rutin dissolved in methanol were added to 0.1 M, 10 ml (1mM) silver nitrate solution (4,7,10) and made up to 100 ml with distilled water.
In this present work, Titanium dioxide nanoparticles (TiO2 NPs) successfully synthesized using the chemical as well as the green synthesis routine. The ethanol provoked the chemical reduction of ions. In the green synthesis, jasmine flower extract was used as a reducing and stabilizing agent because it contains alkaloids, coumarins, flavonoids. The Rutile phase of TiO2 NPs with an average ...
Silver nanoparticles (Ag NPs) have been used in many studies due to their inhibitory properties on microorganisms such as bacteria and viruses. In recent years, due to global problems such as environmental pollution, the green synthesis (biosynthesis) method is frequently preferred because it is sim …
Why green methods for synthesis of nanoparticles? Currently, there are numerous chemical and physical methods available in the literature for production of nanomaterials, which deliver a higher rate of production and well-controlled size and shape of nanomaterials but these approaches are discouraging due to higher loss of energy and capital, use of noxious chemicals, and production of large ...
Green Synthesis of Chitosan-coated Tin Dioxide Nanoparticles Using Moringa oleifera Flower Extract Against Breast Cancer via the Caspase-dependent Apoptotic ... (2017). Synthesis and morphology characterization of SnO2 nanoparticles by hydrothermal method. International Journal of Bio-Inorganic Hybrid Nanomaterials, 6(1), 29-32. Google Scholar.