Time evolution of protein corona formed by polystyrene nanoplastics and urease.

Nanoplastics, as an emerging pollutant in the environment, have the potential to adsorb various macromolecules onto the surface to form protein corona that may change the physicochemical properties and environmental fate of themselves, which deepens the uncertainty of their environmental hazards. Hence, in present study, we investigated the interaction between polystyrene nanoplastics and urease that forms protein corona over time in different conditions with atomic force microscopy, zeta potential, hydrodynamic diameter, and infrared spectroscopy. According to our results, polystyrene nanoplastics adsorbed urease and formed hard corona, changing the secondary structure of urease, and that the physicochemical properties of protein corona changed and stabilized over time. We concluded that even in a single-protein system, a dynamic process where protein molecules simultaneously adsorb onto and desorb from the surface of nanoplastics runs through the entire interaction. And we found that the formation and evolution of protein corona were governed by various interlinked factors (e.g., pH and nanoplastic surface modification types) instead of dominated by individual factor. This study aims to improve the knowledge about the formation of nanoplastic-protein corona and thus provide a reference for better evaluation of their environmental risk.