Synergistic effects of marine pollutants and microplastics on the destabilization of lipid bilayers

The increasing production of plastic worldwide results in increasing amounts of plastic waste dumped into the oceans. Plastic waste is fragmenting into smaller pieces up to micro and nanoplastics, which may cross physiological barriers and affect the functions of living organisms. Microplastics can travel with rain and clouds; they are present in soil, snow-capped mountains, and even in the organs and blood of human beings. The potential health implications of microplastics in living organisms raise concerns and are intensively investigated. Recently, we reported the effect of mechanical stretching of microplastics on a lipid bilayer. By combining experimental and theoretical approaches, we have shown that microplastic particles adsorbed on lipid membranes increase membrane stress even at low particle concentrations. In this manuscript, we demonstrate the synergetic effect of marine pollutants on the mechanical interaction induced by microplastics. For this purpose, bare microplastics are incubated in seawater containing marine pollutants. We show that pollutants, such as chemical solvents, significantly increase the mechanical stretching induced by microplastics. In turn, microplastics can be viewed as vectors for solvent molecules, facilitating their penetration into the core of lipid membranes and thus strongly affecting their biophysical properties.