Characterization of chemical mediated synthesis of silver nanoparticles (Ag-NPs) and their antibacterial efficacy against selected bacterial pathogens.

Nanoparticle research is currently an area of intense scientific interest due to a wide variety of potential applications. The main objective of the present study is focused on synthesis of silver nanoparticles by two different techniques using tri-sodium citrate as a reducing agent by the reduction of silver nitrate to get different types of silver nanoparticles. Synthesis of silver nanoparticles was carried out using tri-sodium citrate as reducing agent and silver nitrate as an inducer by constant heating and cyclic heating technique. The silver nanoparticle was characterized by UV-visible spectroscopy, SEM and XRD to analyse the size, morphology and chemical composition. The formation of the silver nanoparticles was confirmed by changing colour and monitored using UVvisible spectroscopy. The UV-visible spectrum revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima at 450-460 nm. SEM micrograph demonstrates the spherical shaped and some irregular shaped nanoparticles with the size range of 60- 80nm. XRD pattern at 2θ deg showed the whole spectrum value ranging from 20o to 80o by displaying intense peaks at 38.08o indicating that the particle was made of pure silver. Ag-NPs were subjected to perform antibacterial activity against selected bacterial pathogens. Maximum inhibition activity was noticed against Shigella sp. (25mm) using silver nanoparticle mediated by trisodium citrate with constant heating. The outcome of results clearly pin points that the silver nanoparticles produced using tri-sodium citrate as reducing agent and silver nitrate as an inducer by constant heating is a highly efficient and cost effective technique.