Capture on High Curvature Region: Aggregation of Colloidal Particle Bound to Giant Phospholipid Vesicles

TL;DR

This paper theoretically investigates how colloidal particles bound to giant phospholipid vesicles preferentially aggregate in high curvature regions, reducing membrane elastic energy, based on Helfrich curvature elasticity theory.

Contribution

It introduces a theoretical model explaining the aggregation of colloidal particles on vesicles' high curvature regions, highlighting energy reduction mechanisms.

Findings

Colloidal beads in concave regions lower energy by ~20 k_B T.

Beads can be distributed freely along the waist of axisymmetric vesicles.

Aggregation driven by reduction in membrane elastic energy.

Abstract

A very recent observation on the membrane mediated attraction and ordered aggregation of colloidal particles bound to giant phospholipid vesicles (I. Koltover, J. O. R\"{a}dler, C. R. Safinya, Phys. Rev. Lett. {\bf 82}, 1991(1999)) is investigated theoretically within the frame of Helfrich curvature elasticity theory of lipid bilayer fluid membrane. Since the concave or waist regions of the vesicle possess the highest local bending energy density, the aggregation of colloidal beads on these places can reduce the elastic energy in maximum. Our calculation shows that a bead in the concave region lowers its energy $\sim 20 k_B T$. For an axisymmetrical dumbbell vesicle, the local curvature energy density along the waist is equally of maximum, the beads can thus be distributed freely with varying separation distance.