Insight into the binding and conformational changes of hemoglobin/lysozyme with bimetallic alloy nanoparticles using various spectroscopic approaches

This study explores the adsorption and binding interaction of bovine hemoglobin (BHb) and lysozyme (Lys) with gold/silver alloy nanoparticles (Au/Ag alloy NPs) using various spectroscopic approaches. The fluorescence behaviour of tryptophan residues of the proteins after Au/Ag alloy NPs addition revealed that the static quenching interactions. The changes in the morphology of Au/Ag alloy NPs upon BHb/Lys addition are characterized by HRTEM analysis. Further, the conjugation of BHb/Lys with Au/Ag alloy NPs is evident from zeta potential and dynamic light scattering (DLS) techniques. The absorption profiles of Au/Ag alloy NPs with BHb/Lys resulted in the shift to the longer wavelength of surface plasmon resonance (SPR) band indicating the changes of refractive index around the NPs surface due to the proteins adsorption. The alteration in the structure of proteins with Au/Ag alloy NPs is evaluated using Fourier-transform infrared (FT-IR), absorption and circular dichroism (CD) measurements. The outcome of this study could be useful to understand the binding interaction of BHb/Lys proteins on Au/Ag alloy NPs and also to identify the health hazards and potential risks associated with Au/Ag alloy NPs. (C) 2019 Elsevier B.V. All rights reserved.