Greener Synthesis of Silver Nanoparticles using Waste of Onion Allium cepa and Quercetin a comparative study

Abstract

Silver nanoparticles are one of the most widely used nanoparticles currently, finding applications in fields of nanobiotechnology, diagnostics, bio-sensing, cosmetics and material science. Presently most of the nanoparticles used are synthesized through the chemical route thus creating a threat to the environment. Alternately green synthesis of nanoparticles has become an area of interest for researchers worldwide in the last decade. This study investigates the potential of onion waste extract for green synthesis of silver nanoparticles along with pure biomolecule quercetin, a major component of the onion waste. The present study includes the characterization of synthesized nanoparticles through scanning electron microscopy, X-ray diffraction and UV-VIS spectrophotometry, which revealed that spherical nanoparticles with mean diameter of 10nm were synthesized. As quercetin is a polyphenol molecule, hence change in its antioxidant behaviour in the bound and free form was also determined. Through this study, differences in the properties of nanoparticles synthesized using purified biomolecules and natural extracts was brought into light. The synthesized particles were assessed for their antioxidant and antimicrobial potential. Nanoparticles synthesized using onion scored higher radical scavenging activities in ABTS and DPPH assays. In case of antimicrobial activity, particles synthesized using quercetin were more potent.