Effect of the chemical nature of polyoxometalate complexes on redox processes leading to the formation of metallic silver nanoparticles

2011 ◽  
Vol 47 (1) ◽  
pp. 14-20 ◽  
Author(s):  
A. V. Barna ◽  
Ya. D. Lampeka
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Nature ◽  
Metallic Silver ◽  
Redox Processes

Green Synthesis of Silver Nanoparticles by Allamanda cathartica L. Leaf Extract and Evaluation for Antimicrobial Activity

2013 ◽  
Vol 6 (4) ◽  
pp. 2260-2268
Author(s):  
M. Linga Rao ◽  
Bhumi G ◽  
Savithramma N
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Fusarium Species ◽  
Inhibition Zone ◽  
Fungal Species ◽  
Green Technology ◽  
Metallic Silver ◽  
Synthesis Of Nanoparticles ◽  
Aqueous Leaf Extract

Silver nanoparticles (SNPs) exhibit tremendous applications in medicine as antimicrobial agent.  The use of different parts of plants for the synthesis of nanoparticles is considered as a green technology as it does not involve any harmful chemicals.  In the present study, we report a rapid biosynthesis of silver nanoparticles from aqueous leaf extract of medicinal plant Allamanda cathartica.  The active phytochemicals present in the plant were responsible for the quick reduction of silver ion to metallic silver nanoparticles. The reduced silver nanoparticles were characterized by using UV-Vis spectrophotometry, Scanning Electron Microscope (SEM), Energy Dispersive Analysis of X-ray (EDAX) and Atomic Force Microscopy (AFM).  The spherical shaped silver nanoparticles were observed and it was found to 19-40 nm range of size.  These phytosynthesized SNPs were tested for their antimicrobial activity and it analyzed by measuring the inhibitory zone. A. cathartica aqueous leaf extract of SNPs showed highest toxicity to Pseudomonas followed by Klebsiella, Bacillus and E. coli and lowest toxicity towards Proteus. In fungal species, highest inhibition zone was noted against Rhizopus followed by Curvularia, Aspergillus flavus and Aspergillus niger and minimum inhibition zone was observed against Fusarium species.  These results suggest a promising potential of Indian plant-based green chemistry for production of SNPs for biomedical and nanotechnology applications.

Eco-friendly biosynthesis metallic silver nanoparticles using Aegle marmelos (Indian bael) and its clinical and environmental applications

2021 ◽  
Author(s):  
Gattu Sampath ◽  
Muthusamy Govarthanan ◽  
Neelamegam Rameshkumar ◽  
Dai-Viet N. Vo ◽  
Muthukalingan Krishnan ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Environmental Applications ◽  
Metallic Silver ◽  
Aegle Marmelos

Synthesis of metallic silver nanoparticles decorated mesoporous SnO 2 for removal of methylene blue dye by coupling adsorption and photocatalytic processes

2017 ◽  
Vol 346 ◽  
pp. 77-88 ◽  
Author(s):  
M.A. Ahmed ◽  
M.F. Abdel Messih ◽  
E.F. El-Sherbeny ◽  
Suzan F. El-Hafez ◽  
Aliaa M.M. Khalifa
Keyword(s):  
Methylene Blue ◽  
Silver Nanoparticles ◽  
Metallic Silver ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Photocatalytic Processes

Green synthesis, structural characterization, and catalytic activity of silver nanoparticles stabilized with Bridelia retusa leaf extract

2018 ◽  
Vol 7 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Ramesh Vinayagam ◽  
Thivaharan Varadavenkatesan ◽  
Raja Selvaraj
Keyword(s):  
Silver Nanoparticles ◽  
Rhodamine B ◽  
Leaf Extract ◽  
Dye Degradation ◽  
Synthesis Method ◽  
Degradation Process ◽  
Spectroscopic Studies ◽  
Metallic Silver ◽  
X Ray ◽  
Bridelia Retusa

Abstract:An environmentally benign method to synthesize silver nanoparticles (SNPs) using the leaf extract ofBridelia retusawas developed. The UV-Vis absorption spectrum of the synthesized SNPs displayed a surface plasmon peak at 420 nm. Scanning electron microscopy (SEM) revealed the irregular shaped nanoparticles, and energy dispersive X-ray (EDX) ascertained the presence of metallic silver by showing a strong signal at 3 eV. The crystalline structure of metallic silver was confirmed by X-ray diffraction (XRD). The mean size of the SNPs was calculated as 16.21 nm. Fourier infrared (FT-IR) spectroscopic studies displayed specific bands for various functional groups and affirmed the function of reduction and stabilization of SNPs. The stability was endorsed by the zeta potential value of −18.1 mV. The results evidenced that this leaf extract-mediated synthesis method is eco-friendly, rapid, and cheap. The catalytic power of the SNPs was investigated for Rhodamine B dye degradation. The SNPs completely degraded Rhodamine B within 9 min; thus, the dye degradation process was very rapid. The pseudo-first order degradation constant was found out to be 0.1323 min−1. This paves the way for the future development of novel nano-catalysts to reduce environmental pollution.

scholarly journals Transformation-dissolution reactions partially explain adverse effects of metallic silver nanoparticles to soil nitrification in different soils

2018 ◽  
Vol 37 (8) ◽  
pp. 2123-2131 ◽  
Author(s):  
Jessica Bollyn ◽  
Bernd Willaert ◽  
Bart Kerré ◽  
Claudia Moens ◽  
Katrien Arijs ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Adverse Effects ◽  
Metallic Silver ◽  
Soil Nitrification ◽  
Different Soils

Synthesis of Silver Nanoparticles and their Biomedical Applications - A Comprehensive Review

2019 ◽  
Vol 25 (24) ◽  
pp. 2650-2660 ◽  
Author(s):  
Rajasree Shanmuganathan ◽  
Indira Karuppusamy ◽  
Muthupandian Saravanan ◽  
Harshiny Muthukumar ◽  
Kumar Ponnuchamy ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Biomedical Applications ◽  
Antibacterial Agents ◽  
Cost Effective ◽  
Metallic Silver ◽  
Synthesis Methods ◽  
Burn Wound ◽  
Chemical Methods ◽  
Biological Sources ◽  
Physical And Chemical

Generally, silver is considered as a noble metal used for treating burn wound infections, open wounds and cuts. However, the emerging nanotechnology has made a remarkable impact by converting metallic silver into silver nanoparticles (AgNPs) for better applications. The advancement in technology has improved the synthesis of NPs using biological method instead of physical and chemical methods. Nonetheless, synthesizing AgNPs using biological sources is ecofriendly and cost effective. Till date, AgNPs are widely used as antibacterial agents; therefore, a novel idea is needed for the successful use of AgNPs as therapeutic agents to uncertain diseases and infections. In biomedicine, AgNPs possess significant advantages due to their physical and chemical versatility. Indeed, the toxicity concerns regarding AgNPs have created the need for non-toxic and ecofriendly approaches to produce AgNPs. The applications of AgNPs in nanogels, nanosolutions, silver based dressings and coating over medical devices are under progress. Still, an improvised version of AgNPs for extended applications in an ecofriendly manner is the need of the hour. Therefore, the present review emphasizes the synthesis methods, modes of action under dissipative conditions and the various biomedical applications of AgNPs in detail.

scholarly journals New Relevant Descriptor of Linear QNAR Models for Toxicity Assessment of Silver Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1459
Author(s):  
Alexey Kudrinskiy ◽  
Pavel Zherebin ◽  
Alexander Gusev ◽  
Olga Shapoval ◽  
Jaeho Pyee ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Biological Activity ◽  
Colloidal Stability ◽  
Chemical Nature ◽  
Equilibrium Concentration ◽  
Toxicity Assessment ◽  
Yeast Cells ◽  
Wide Range ◽  
Silver Nps ◽  
Living Organisms

The use of silver nanoparticles (NPs) in medical, industrial and agricultural fields is becoming more widespread every year. This leads to an increasing number of experimental toxicological and microbiological studies of silver NPs aimed at establishing the risk–benefit ratio for their application. The following key parameters affecting the biological activity of silver dispersions are traditionally taken into consideration: mean diameter of NPs, surface potential of NPs and equilibrium concentration of Ag+. These characteristics are mainly predetermined by the chemical nature of the capping agent used for stabilization. However, the extent to which they influence the biological activity and the toxicity of silver NPs varies greatly. In this work, dispersions of silver NPs stabilized with a wide array of substances of different chemical nature were used for quantitative evaluation of whether the various measurable properties of silver NPs fit as descriptors of linear QNAR (quantitative nanostructure–activity relationship) models for silver NP toxicity evaluation with respect to a model eukaryotic microorganism—Saccharomyces cerevisiae yeast cells. It was shown that among the factors that determine silver NP toxicity, the charge of particles, their colloidal stability and the ability to generate Ag+ ions carry more importance than the descriptors related to the particle size. A significant synergistic effect between the ζ-potential and the colloidal stability of silver NPs on their toxicity was also discovered. Following this, a new descriptor has been proposed for the integral characterization of the silver dispersion colloidal stability. According to the obtained data, it can be considered applicable for building QNAR models of higher efficacy. The validity testing of the proposed model for theoretical prediction of silver NP toxicity using a wide range of living organisms has shown that this new descriptor correlates with toxicity much better compared to most traditionally used descriptors. Consequently, it seems promising in terms of being used not only in situations involving the rather narrow array of the objects tested, but also for the construction of silver NP toxicity models with respect to other living organisms.

Silver Core - Silver Oxide Shell Nanoparticles Embedded on Mesostructured Silica Films

2008 ◽  
Vol 3 ◽  
pp. 103-114 ◽  
Author(s):  
Guadalupe Valverde-Aguilar ◽  
Jorge A. García-Macedo ◽  
Víctor Rentería-Tapia
Keyword(s):  
Silver Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Silver Oxide ◽  
High Refractive Index ◽  
Oxide Shell ◽  
Metallic Silver ◽  
Type I ◽  
Silver Core

Metallic silver particles in the nanometer size range were obtained in SiO2 matrix by the reduction of AgNO3 with the non-ionic diblock copolymer (Brij 58). Hexagonal mesostructured sol-gel films were synthesized by dip-coating method using the surfactant Brij58 to produce channels into the film, which house the silver nanoparticles. Optical properties of the metallic nanoparticles were studied by UV-Vis spectroscopy, TEM and HRTEM images. The experimental absorption spectrum of the metallic silver nanoparticles exhibits an absorption band located at 438 nm and a shoulder at longer wavelength. The TEM images show randomly distributed silver nanoparticles (Type I) along with some oriented as long line (Type II). Both distributions exhibit a silver oxide shell around of them. The second shell covering the silver core - silver oxide shell system is related to the surfactant. The optical absorption spectrum was modelled using the Gans theory. The fit shows two main contributions related to metallic silver nanoparticles with different axial ratios, and surrounding of a dielectric medium with high refractive index. Presence of the high refractive index silver oxide shell was confirmed by X-ray diffraction technique. The contributions of silver core and silver oxide shell play important roles in the optical properties of the films.

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