Cell-Scale Dynamic Modeling of Membrane Interactions with Arbitrarily Shaped Particles

TL;DR

This paper introduces a computational framework to simulate membrane interactions with arbitrarily shaped particles at the cell scale, capturing complex dynamics and wrapping energetics for diverse geometries.

Contribution

The authors develop a force-based, mesh-based simulation method that accurately models deformable membranes interacting with irregular rigid particles, including novel numerical schemes for adhesion modeling.

Findings

Lower mass ratios promote full membrane wrapping.

Higher mass ratios stabilize partial wrapping and limit reorientation.

The framework effectively simulates diverse particle and vesicle geometries.

Abstract

Modeling membrane interactions with arbitrarily shaped colloidal particles, such as environmental micro- and nanoplastics, at the cell scale remains particularly challenging, owing to the complexity of particle geometries and the need to resolve fully coupled translational and rotational dynamics. Here, we present a force-based computational framework capable of capturing dynamic interactions between deformable lipid vesicles and rigid particles of irregular shapes. Both vesicle and particle surfaces are represented using triangulated meshes, and Langevin dynamics resolves membrane deformation alongside rigid-body particle motion. Adhesive interactions between the particle and membrane surfaces are modeled using two numerical schemes: a vertex-to-vertex mapping and a vertex-to-surface projection. The latter yields more accurate wrapping energetics, as demonstrated by benchmark comparisons against ideal spheres. The dynamic simulations reveal that lower particle-to-vesicle mass ratios facilitate frequent particle reorientation and complete membrane wrapping, while higher mass ratios limit orientation changes and stabilize partial wrapping. To illustrate the framework's versatility, we simulate interactions involving cubical, rod-like, bowl-shaped, and tetrahedral particles with spherical, cigar-shaped, or biconcave vesicles. This generalizable modeling approach enables predictive, cell-scale studies of membrane-particle interactions across a wide range of geometries, with applications in environmental biophysics and nanomedicine.