Coexistence of dilute and densely packed domains of ligand-receptor bonds in membrane adhesion

TL;DR

This paper investigates the stability and organization of ligand-receptor bonds in membrane adhesion, revealing coexistence of dilute and dense bond domains influenced by membrane fluctuations and bond mobility.

Contribution

It provides a theoretical analysis of micro-domain stability and predicts coexistence of bond regimes, aligning with recent experimental findings.

Findings

Dense and sparse bond regimes are separated by a free energy barrier.

Mobile bonds can coexist in both dense and sparse domains.

Theoretical results match recent experimental observations.

Abstract

We analyze the stability of micro-domains of ligand-receptor bonds that mediate the adhesion of biological model membranes. After evaluating the effects of membrane fluctuations on the binding affinity of a single bond, we characterize the organization of bonds within the domains by theoretical means. In a large range of parameters, we find the commonly suggested dense packing to be separated by a free energy barrier from a regime in which bonds are sparsely distributed. If bonds are mobile, a coexistence of the two regimes should emerge, which agrees with recent experimental observations.