Membrane-Mediated Interactions Between Nonspherical Elastic Particles

TL;DR

This study models how deformable, non-spherical vesicles interact with lipid membranes, revealing how their shape and elasticity influence wrapping states and membrane-mediated interactions, with implications for drug delivery design.

Contribution

It introduces a theoretical framework for understanding the interactions of deformable, non-spherical vesicles with membranes, extending beyond hard particle models.

Findings

Softness increases stability of partially wrapped states.

Membrane mediates attractive or repulsive interactions depending on vesicle wrapping.

Predicted interaction behaviors depend on vesicle shape and wrapping degree.

Abstract

The transport of particles across lipid-bilayer membranes is important for biological cells to exchange information and material with their environment. Large particles often get wrapped by membranes, a process which has been intensively investigated in the case of hard particles. However, many particles in vivo and in vitro are deformable, e.g., vesicles, filamentous viruses, macromolecular condensates, polymer-grafted nanoparticles, and microgels. Vesicles may serve as a generic model system for deformable particles. Here, we study non-spherical vesicles with various sizes, shapes, and elastic properties at initially planar lipid-bilayer membranes. Using the Helfrich Hamiltonian, triangulated membranes, and energy minimization, we predict the interplay of vesicle shapes and wrapping states. Increasing particle softness enhances the stability of shallow-wrapped and deep-wrapped states over non-wrapped and complete-wrapped states. The free membrane mediates an interaction between partial-wrapped vesicles. For the pair interaction between deep-wrapped vesicles, we predict repulsion. For shallow-wrapped vesicles, we predict attraction for tip-to-tip orientation and repulsion for side-by-side orientation. Our predictions may guide the design and fabrication of deformable particles for efficient use in medical applications, such as targeted drug delivery.