Azadirachta Indica and Brassica Oleracea Mediated Green Synthesis vs. Chemical Synthesis of Silver Nanoparticles and their Antibacterial Properties

An alternative source of synythesis of nanoparticles is plant extract rather than chemical methods. This is because of presence of secondary metabolites or reducing agents in plant extract which are responsible for nanoparticles synthesis. In bioaccumulation, this synthesis depends upon the availability of particular enzymes or protein in plant extract. Considering the therapeutic potentials of nanoparticles, this work has been designed to find out antibacterial activity of silver nanoparticles. Objectives of this work are - preparation of silver nanoparticles chemically and biologically, characterisation of nanoparticles and evaluation of their antibacterial activities against E. coli. Comparision of antibacterial properties were made among NaBH4- AgNPs, Azadirachta indica (Neem) extract AgNPs and Brassica oleracea (Cauliflower) extract AgNPs. UV- absorption spectra of chemically and biologically synthesized AgNPs at different time intervals were measured using UV-Visible spectrophotometer. Particle size of AgNPs was measured by dynamic laser scattering technique (DLS) using Malvern Aimil Zetasizer. The obtained silver nanoparticles were of sizes between 10 nm and 100 nm. It was clear from antibacterial activities that biologically synthesized AgNPs were more effective against E. coli than chemically synthesized AgNPs.