Fluctuation induced attraction between adhesion sites of supported membranes

TL;DR

This study investigates how membrane fluctuations induce long-range attractive interactions between adhesion sites, revealing a logarithmic potential that depends on membrane stress and surface interactions.

Contribution

It introduces a combined analytical and simulation approach to quantify fluctuation-mediated forces between membrane adhesion sites, highlighting the effects of membrane stress and surface interactions.

Findings

The potential of mean force is a long-range logarithmic attraction between adhesion sites.

Membrane stress alters the strength of the fluctuation-induced attraction.

Surface interactions can screen the fluctuation-mediated potential at large distances.

Abstract

We use scaling arguments and coarse grained Monte Carlo simulations to study the fluctuation mediated interactions between a pair of adhesion sites of a bilayer membrane and a supporting surface. We find that the potential of mean force is an infinitely long range attractive potential that grows logarithmically with the pair distance $r$: $\phi(\vec{r})/k_BT=c\ln r$, where the constant $c=2$ and $c=1$ for non-stressed and stressed membranes, respectively. When, in addition to excluded volume repulsion, the membrane also interacts with the underlying surface through a height-dependent attractive potential, the potential $\phi(\vec{r})$ is screened at large pair distances.