Spectroscopic studies on polystyrene nanoparticle-induced changes in the structure and properties of human serum...

Nanoplastics are considered a potential threat to human health and the environment due to their persistence and ubiquity. Upon entrance into the biological systems, nanoplastics can interact with proteins, forming "protein corona". In this study, the interactions of polystyrene nanoparticles (PSNPs) with human serum albumin (HSA) were investigated by multiple spectroscopic techniques. UV-Vis spectroscopic and spectrofluorimetric studies demonstrated that PSNPs formed a spontaneous ground-state complex with HSA with high affinity. Analysis of circular dichroism (CD) spectra revealed that PSNPs induced changes in the secondary structure of HSA. Adsorption of HSA on PSNPs slightly increased the stability of the protein but reduced its esterase activity by competitive inhibition compared to the native protein. PSNPs also significantly diminished the antioxidant capacity of HSA. These findings provide important insights into the interactions of PSNPs with HSA and contribute towards a better understanding of nanoplastic toxicity.