Green Synthesis and Characterization of Bimetallic and Trimetallic Nanoparticles Using Plant Extract and Evaluation of Enhancement in Antioxidant Bio Efficacy

Abstract

The present thesis is devoted towards the phyto-synthesis and characterisation of MMNPs (Ag, Au and Pt), BMNPs (Au/Ag, Au/Pt and Ag/Pt) and TMNPs (Au/Ag/Pt) NPs using CBE with special reference to evaluation of antioxidant bio-efficacy. The present work highlights that extract is a rich source of phenolic and flavonoid content. Thus, single step, facile, cheap and eco-friendly approach has been used for the synthesis of various NPs in which extract in itself acts as a reducing and capping agent for the NPs. newline The various operational parameters such as pH, temperature, salt concentration and concentration of were optimised for various NPs. The UV-Visible spectroscopy was used to perform the preliminary formation of NPs. The morphology, particle size, composition analysis and stability of NPs were investigated using various techniques such as XRD, SEM, TEM, EDX, XPS, Zeta potential, and FT-IR spectroscopy which confirm the formation of NPs. All the phyto-synthesised NPs have fcc structures having mainly spherical morphology but some pentagonal, hexagonal and polyhedral shaped particles were also seen. The size of MMNPs, BMNPs and TMNPs lies in the range of 16-28 nm, 13-45 nm and 11-55 nm, respectively. newline The antioxidant bio-efficacy of phyto-synthesised NPs was evaluated using three bio-assays, DPPH, ABTS and Fenton s Assay. Among all the phyto-synthesised NPs, TMNPs were the most stable and exhibited highest antioxidant bio-efficacy and the order of antioxidant bio-efficacy in all three assays were found to be: Au/Ag/Pt TMNPsgt Au/Pt BMNPsgt Ag/Pt BMNPsgt Au/Ag BMNPsgt Pt NPsgt Au NPsgt Ag NPs. The investigated promising antioxidant bio-efficacy of synthesised NPs can be used after further validating them using various methods in biomedical field as herbal antioxidant agents. newline newline newline