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.