GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES.

Nanoparticles have altered properties because of their size and result of which they have found enormous applications. Silver nanoparticles have been known to have antimicrobial properties. Biological synthesis of nanomaterials are not only ecofriendly but also the nanoparticles synthesized have superior properties than those synthesized using physical and chemical methods. In the present study, silver nanoparticles (AgNPs) were synthesized using various plant extracts like fern, jackfruit, and onion. The effect of varying pH of these extracts on the synthesis of AgNPs was studied, and alkaline medium was found to decrease the time taken for synthesis. The synthesized AgNPs were found to have absorption maxima close to 420 nm, and mean size less than 50 nm. The antimicrobial activity of AgNPs was checked against pathogens like, E. coli, S. aureus, S. pyogenes, S. typhi, S. paratyphi A, S. paratyphi B, Shigella and Proteus. The MIC of these AgNPs against E. coli and S. aureus was determined. It was found that these AgNPs when adsorbed on to activated carbon could be used to disinfect water contaminated with E. coli.