Biosynthesis of silver nanoparticles using the leaf extract of Amaranthus tristis was evaluated in the present report. The biosynthetic approach of nanoparticles synthesis deserves merit in biomedical applications due to its better biocompatibility. The biosynthesized silver nanoparticle was embedded in PVA polymer matrix as dispersed phase to craft an Ag/PVA nanocomposite membrane. The silver nanoparticles and the Ag/PVA nanocomposite membrane were characterized by UV–Vis, FTIR, AFM, SEM and TEM analyses. The membrane was fabricated by varying the ratios of Ag nanoparticles and PVA. Further, these membranes were tested against airborne microbes by exposing in air and compared with the control PVA membrane. 2:8 ratio of Ag: PVA nanocomposite membrane was found to possess a good activity in prevention of microbial growth and hence was studied further and characterized. UV-Vis spectra exhibited the characteristic Surface Plasmon Resonance (SPR) peak at 452 nm for Ag nanoparticle and 442 nm for Ag/PVA nanocomposite membrane (2:8). The AFM analysis of the nanoparticles showed the presence of uniform sized nanoparticles with an average size of 20- 40 nm. This size was further confirmed with TEM analysis and nanoparticles were found to exist in the same size range of 20-40nm. The membrane was further characterized by Energy Dispersive X-ray Spectroscopy (EDS) which confirmed the presence of Ag nanoparticles (24.3 weight% of Ag) in Ag/PVA nanocomposite membrane. The antimicrobial efficiency of Ag/PVA nanocomposite membrane and Ag nanoparticles were tested against Pseudomonas fluorescens and Klebsiella pneumonia.
Keywords: Biosynthesis, silver nanoparticles, PVA membrane, antimicrobial activity, air-borne microbes.