Background: Nanotechnology explores a variety of promising approaches in the area of material sciences on a molecular level, and silver nanoparticles (AgNPs) are of leading interest in the present scenario This review is a comprehensive contribution in the field of green synthesis, characterization, and biological activities of AgNPs using different biological sources Methods: Biosynthesis of AgNPs can be accomplished by physical, chemical, and green synthesis; however, synthesis via biological precursors has shown remarkable outcomes In available reported data, these entities are used as reducing agents where the synthesized NPs are characterized by ultraviolet-visible and Fourier-transform infrared spectra and X-ray diffraction, scanning electron microscopy, and transmission electron microscopy Results: Modulation of metals to a nanoscale drastically changes their chemical, physical, and optical properties, and is exploited further via antibacterial, antifungal, anticancer, antioxidant, and cardioprotective activities Results showed excellent growth inhibition of the microorganism Conclusion: Novel outcomes of green synthesis in the field of nanotechnology are appreciable where the synthesis and design of NPs have proven potential outcomes in diverse fields The study of green synthesis can be extended to conduct the in silco and in vitro research to confirm these findings

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Green nanotechnology: a review on green synthesis of silver nanoparticles - an ecofriendly approach.

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed.

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Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature

The present study was aimed to synthesis copper oxide nanoparticles by green chemistry method Copper oxide nanoparticles (CuO–NPs) were synthesized using Solanum lycopersicum aqueous leaf extract The synthesized CuO–NPs were characterized by UV–visible spectroscopy, Field emission-scanning electron microscopy (FE-SEM), High resolution-transmission electron microscopy (HR-TEM), Energy dispersive x-ray spectrometer (EDX), and Dynamic light scattering spectrometer (DLS) FE-SEM and TEM observation showed that the average size of 20–40 nm with spherical shape of CuO–NPs and the presence of phytochemicals which are responsible for reduction and stabilization were studied by FT-IR XRD studies revealed the monocyclic crystalline phase of CuO–NPs The synthesized CuO–NPs showed significant antibacterial activity against both Gram positive and Gram negative bacterial pathogens, assayed using agar well diffusion method and synthesized CuO–NPs induce significant morphological changes to bacterial pathogens, determined using FE-SEM Furthermore, photocatalytic degradation of crystal violet (CV) under visible light irradiation using CuO–NPs was performed Synthesized nanoparticles exhibited 97% degradation activity for CV Overall our studies supported the eco-friendly, green synthesized CuO–NPs can be used as potential biocidal and photocatalytic agents

https://iopscience.iop.org/article/10.1088/2053-1591/aad426/pdf

Antibacterial and photocatalytic activity of copper oxide nanoparticles synthesized using Solanum lycopersicum leaf extract

A facile, eco-friendly synthesis of zinc oxide nanoparticles (ZnO NPs) employing Bauhinia tomentosa leaf extract as bioreducing agent was reported. The green-synthesized ZnO NPs were characterized by UV–Vis, TEM, EDX, XRD, and FTIR analyses. The formation of ZnO NPs was confirmed by the appearance of characteristic SPR peak at 370 nm due to the collective oscillation of electrons in the conduction band in UV–Vis spectra. The hexagonal morphology exhibiting nanosized ZnO was observed from the TEM and XRD analyses. The chemical bonds present in the as-synthesized ZnO NPs were identified by FTIR analysis. ZnO NPs showed a significant antibacterial activity against Gram-negative bacteria P. aeruginosa and E. coli than Gram-positive bacteria. Results of this study demonstrated that B. tomentosa leaf extract containing phytochemicals such as alkaloids, terpenoids, flavonoids, tannins, carbohydrates, and sterols possess bioreducing property for ZnO synthesis and the obtained ZnO NPs could be employed effectively as a better bactericidal agent for biological applications.

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Biosynthesis, characterization, and antibacterial activity of zinc oxide nanoparticles derived from Bauhinia tomentosa leaf extract

Biogenic synthesis and antibacterial activity of controlled silver nanoparticles using an extract of Gongronema Latifolium

The present study reports an eco-friendly, biosynthesis of silver nanoparticles (AgNPs) using stem bark extract of Diospyros montana. Initially, the synthesis of AgNPs was confirmed by visual observation as color change. Further, the morphology of the biosynthesized nanoparticles, average size and presence of elemental silver were characterized by UV–Visible spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray and dynamic light scattering spectrometer. Qualitative phytochemical screening and FTIR spectral peaks supported the role of phytochemicals in bark extract for the metal reduction, stabilization and capping of silver nanoparticles. XRD studies demonstrated that crystalline nature and their average size of nanoparticles was 28 nm as determined by Scherrer’s formula. The antioxidant ability of AgNPs and plant extract was analyzed using DPPH and Hydrogen peroxide assay. The percentage of DPPH and H2O2 activity was increased with increasing concentration of AgNPs. In vitro antibacterial effect of various concentration of AgNPs was investigated against both Gram positive (B.subtilis and S.aureus) and Gram negative (E.coli and K.aerogenes) bacterial strains. The result shows that biosynthesized AgNPs have significant antibacterial activity.

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M. Diviya Josebin

Papers

Biosynthesis of silver nanoparticles using stem bark extracts of Diospyros montana and their antioxidant and antibacterial activities