Coarse grained molecular simulations of membrane adhesion domains

TL;DR

This study uses coarse grained molecular simulations to explore how membrane adhesion domains form as a first order phase transition influenced by interactions between adhesion bonds and membrane undulations.

Contribution

It demonstrates that membrane adhesion domain formation is a first order phase transition driven by pairwise and many-body interactions, aligning with a 2D lattice model.

Findings

Adhesion domain formation is a first order phase transition.

A second transition into a hexatic phase occurs with stronger attraction.

Simulation results agree with the Weil-Farago 2D lattice model.

Abstract

We use a coarse grained molecular model of supported lipid bilayers to study the formation of adhesion domains. We find that this process is a first order phase transition, triggered by a combination of pairwise short range attractive interactions between the adhesion bonds and many-body Casimir-like interactions, mediated by the membrane thermal undulations. The simulation results display an excellent agreement with the recently proposed Weil-Farago 2D lattice model, in which the occupied and empty sites represent, respectively, the adhesion bonds and unbound segments of the membrane. A second phase transition, into a hexatic phase, is observed when the attraction between the adhesion bonds is further strengthened.