Membrane adhesion via competing receptor/ligand bonds

TL;DR

This paper develops a statistical-mechanical model for membrane adhesion involving two types of receptor/ligand bonds, revealing how their interactions influence phase behavior and membrane binding states.

Contribution

It introduces a double-well potential framework to describe membrane interactions with two bond types, providing explicit scaling laws and Monte Carlo validation.

Findings

Membranes exhibit unbound and bound states depending on receptor/ligand concentrations.

Length mismatch can induce lateral phase separation in membranes.

Scaling laws for unbinding and phase separation critical points are derived.

Abstract

The adhesion of biological membranes is controlled by various types of receptor and ligand molecules. In this letter, we present a statistical-mechanical model for membranes that interact via receptor/ligand bonds of two different lengths. We show that the equilibrium phase behavior of the membranes is governed by an effective double-well potential. The depths of the two potential wells depend on the concentrations and binding energies of the receptors and ligands. The membranes are unbound for small, and bound for larger potential depths. In the bound state, the length mismatch of the receptor/ligand bonds can lead to lateral phase separation. We derive explicit scaling laws for the critical points of unbinding and phase separation, and determine the prefactors by comparison with Monte Carlo results.