Protein corona as a mediator in antibiotic adsorption onto microplastics: Mechanisms and implications

Microplastics are emerging pollutants capable of adsorbing antibiotics in the environment through interactions mediated by biological molecules such as proteins, ultimately posing risks to human health. However, direct evidence demonstrating that microplastics and antibiotics form chemical-adsorption products has not been explored. One key mechanism contributing to their co-exposure risks during their transmission is biofilm formation, particularly the development of a protein corona, which may also serve as a potential virulence mechanism. In this study, the interactions and adsorption processes among microplastics, proteins, and antibiotics within biofilm formation were innovatively analysed using molecular docking. Hydrophobic interactions contributing to the formation of a stable protein corona have been evidenced even in vitro digestive simulations. Notably, the presence of a protein corona on microplastics enhances the maximum adsorption capacity of antibiotics by 51.9 ± 2.7 %-64.7 ± 3.5 %, without affecting the chemical adsorption mode on Site II or the heterogeneous diffusion mechanism. Furthermore, compared to previous studies, this research provides compelling evidence that sulfamethoxazole interacts with Glu 166 in Site II of bovine serum albumin with high accuracy. Overall, this study addresses a previously overlooked aspect of toxicological research by offering new insights into pollutant adsorption facilitated by the protein corona on microplastics.