Nanoplastic Shape Effects on Lipid Bilayer Permeabilization

Environmental nanoplastics (ENPs) are generated from natural weathering of larger plastic waste. These nanoplastics are capable of disrupting normal cellular functions. Despite the growing threats of plastic pollution, >90% of current research on interactions between nanomaterials and biological systems employs pristine nanoparticles of uniform shape and size, most often polystyrene (PS) nanospheres. Pristine nanoparticles are incomplete models because true ENP waste is morphologically diverse. In this work, we describe how lipid composition and ENP shape affect particle-membrane interactions, using simulated environmental ENPs (sENPs) and giant unilammelar vesicles (GUVs) as models of plasma membranes. Critically, we provide the first systematic quantitative analysis of how ENP shape controls their capacity to permeabilize membranes. Compared to pristine spherical nanoparticles, sENPs damaged membranes with a wider variety of lipid types and charge states. The capacity to damage membranes is determined in large part by ENP shape: angular, more sharply cornered particles tend to increase membrane disruption, demonstrating how the true biophysical effects of ENP pollution cannot be fully captured using pristine materials alone.