Entropy driven aggregation of adhesion sites of supported membranes

TL;DR

This paper investigates how thermal fluctuations influence the aggregation of adhesion sites in supported membranes, showing that fluctuations reduce the direct interaction strength needed for cluster formation.

Contribution

It introduces a mean field and Monte Carlo simulation approach to quantify the effect of membrane fluctuations on adhesion site aggregation.

Findings

Fluctuation-mediated interactions alone do not cause aggregation.

Thermal fluctuations significantly lower the direct interaction strength needed for clustering.

The required interaction strength is reduced by about half, below thermal energy $k_BT$.

Abstract

We study, by means of mean field calculations and Monte Carlo simulations of a lattice-gas model, the distribution of adhesion sites of a bilayer membrane and a supporting flat surface. Our model accounts for the many-body character of the attractive interactions between adhesion points induced by the membrane thermal fluctuations. We show that while the fluctuation-mediated interactions alone are not sufficient to allow the formation of aggregation domains, they greatly reduce the strength of the direct interactions required to facilitate cluster formation. Specifically, for adhesion molecules interacting via a short range attractive potential, the strength of the direct interactions required for aggregation is reduced by about a factor of two to below the thermal energy $k_BT$.