Computational Study on the Wrapping Dynamics of Arbritrary Shaped Microparticles by Membrane Vesicles at Cellular Scale

Micro and nanoplastics (MNPs) found in natural environments interact with living organisms and cellular membranes in complex and potentially detrimental ways. Understanding the interaction dynamics of microparticles with lipid membranes would provide critical insights into particle uptake mechanisms by cells. Previous studies have mainly focused on spherical particles, but environmental MNPs often feature irregular and anisotropic morphologies. To capture this important characteristic, we developed a mesh-based dynamic simulation to explore the interactions between irregularly shaped microplastics and membrane vesicles. Specifically, the vesicle is numerically represented as a triangulated surface mesh with its deformation described by the Helfrich theory. The particle is also modeled using a triangle mesh with rigid body dynamics, allowing us to study shapes that lack simple analytical expression. A vertex-to-surface method was developed to resolve the nontrivial particle-membrane adhesion in the mesh-based scheme and its accuracy was validated against theoretical predicitions. We simulated interactions between microp of cuboid, spheroid, tetrahedral, and capsid shapes with both spherical and biconcave vesicle membranes. These simulations reveal the influence of particle anisotropy and initial orientation on the wrapping process. Our findings provide critical insights into the mechanisms of microplastic uptake by biological membranes, advancing our understanding of how shape, size, and orientation affect cellular uptake processes.