Interactions of Gold Nanoparticles and Lysozyme by Fluorescence Quenching Method

Abstract

The fluorescence quenching technique was applied to study the interactions between lysozyme and Gold nanoparticles (GNPs). GNPs were synthesized by microwave assisted heating under reflux, using trisodium citrate as the reducing agent. The UV-visible spectra and TEM image were used to characterize the GNPs. The GNPs had a maximum absorption peak at 520 nm, with an average diameter of 13.3 nm. The fluorescence quenching mechanism was studied by Stern-Volmer equation. It was proved that the fluorescence quenching of lysozyme by GNPs was mainly a result of the formation of a lysozyme-GNP complex. Experimental results indicated that the combination reactions of GNPs and lysozyme were static quenching processes. It can be expected that the fluorescence quenching technique could provide a promising tool to study the interactions of GNPs and proteins. The binding constants, the number of binding sites at different temperatures and corresponding thermodynamic parameters ΔG, ΔH, and ΔS were also calculated.