Evaluation of Antimicrobial Activity of Biosynthesized Iron and Silver Nanoparticles Using the Fungi Fusarium Oxysporum and Actinomycetes SP. on Human Pathogens

A simple and reproducible biosynthetic method was employed to synthesize iron and silver nanoparticles which resulted in monodispersed nanoparticles of high concentration. The iron oxide nanoparticles has been widely favored because of low cytotoxicity, biodegradable and reactive surface that can be modified with biocompatible coatings. Silver nanoparticles has been a potent antibacterial, antifungal, anti-viral and anti-inflammatory agent. The reaction process was simple, eco-friendly, inexpensive and easy to handle. Green and chemical methods were employed to synthesize iron and silver nanoparticles. A microbial route to synthesize iron and silver nanoparticles by the fungal strain Fusarium oxysporum sp. and Actinomycetes sp. was done simultaneously. Production of nanoparticles using fungi has some advantages over other organisms as it is easy to handle and require simple raw materials. The obtained iron and silver nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy and the morphology of prepared nanoparticles was confirmed by Transmission electron microscopy. TEM analysis of Iron nanoparticles synthesized by Fusarium oxysporum sp. showed 20-40 nm sized particles. These particles exhibited maximum antibacterial activity against Bacillus, E. coli and Staphylococcus sps. TEM images of biosynthesized silver nanoparticles were of smaller size (10-20 nm). The microbially synthesized silver nanoparticles using Actinomycetes were found to be highly toxic against different human pathogens. The mechanism of antimicrobial property of nanoparticle lies with the fact that the extremely small size means a large surface area relative to the volume, which effectively covers the microorganisms and reduce oxygen supply for respiration. It was found that smaller silver nanoparticles have a greater antibacterial activity.