Hard Spheres in Vesicles: Curvature-Induced Forces and Particle-Induced Curvature

TL;DR

This study investigates how colloidal particles inside lipid vesicles interact with membrane curvature, showing that larger particles tend to move towards regions of higher curvature and can influence vesicle shape.

Contribution

It introduces a model linking particle size, membrane curvature, and vesicle shape changes, highlighting the role of particle-induced curvature effects.

Findings

Larger spheres are pinned to regions of higher curvature.

Particles can induce shape changes in flexible vesicles.

Membrane shape influences particle arrangement.

Abstract

We explore the interplay of membrane curvature and nonspecific binding due to excluded-volume effects among colloidal particles inside lipid bilayer vesicles. We trapped submicron spheres of two different sizes inside a pear-shaped, multilamellar vesicle and found the larger spheres to be pinned to the vesicle's surface and pushed in the direction of increasing curvature. A simple model predicts that hard spheres can induce shape changes in flexible vesicles. The results demonstrate an important relationship between the shape of a vesicle or pore and the arrangement of particles within it.