Interaction study of human serum albumin and ZnS nanoparticles using fluorescence spectrometry

The present work is designed to investigate the interaction of ZnS nanoparticles (NPs) with human serum albumin (HSA) using florescence spectroscopy. The results revealed the presence of static type of quenching mechanism in the binding of ZnS NPs to HSA. The association constant (Ka) between ZnS NPs and HSA were obtained according to modified Stern–Volmer equation. Based on the thermodynamic parameters extracted from the fluorescence data, it was shown that the binding of ZnS NPs to HSA was driven mainly by van der Waals and hydrogen bonding interactions. Further, the competitive experiments using the site markers suggested that the binding site of ZnS NPs to HSA was located in the region of subdomain IIA (sudlow site I). Furthermore, synchronous fluorescence spectroscopy and temperature-induced denaturation study revealed the possibility of the change in the secondary structure of HSA molecules during the bonding and interaction with ZnS NPs.