Formation of adhesion domains in stressed and confined membranes

TL;DR

This study uses computer simulations to explore how confinement and surface tension influence the formation of adhesion domains in supported lipid bilayers, revealing that confinement significantly affects the transition while surface tension has minimal impact.

Contribution

It provides new insights into how confinement and negative tension modify adhesion domain formation in supported membranes through detailed simulation analysis.

Findings

Confinement significantly alters the condensation transition of adhesion bonds.

Surface tension has a minor effect on the adhesion domain transition.

Negative tension effects are mitigated by adhesion bond entropy in supported membranes.

Abstract

The adhesion bonds connecting a lipid bilayer to an underlying surface may undergo a condensation transition resulting from an interplay between a short range attractive potential between them, and a long range fluctuation-induced potential of mean force. Here, we use computer simulations of a coarse-grained molecular model of supported lipid bilayers to study this transition in confined membranes, and in membranes subjected to a non-vanishing surface tension. Our results show that confinement may alter significantly the condensation transition of the adhesion bonds, whereas the application of surface tension has a very minor effect on it. We also investigate domain formation in membranes under negative tension which, in free membranes, causes enhancement of the amplitude of the membrane thermal undulations. Our results indicate that in supported membranes, this effect of a negative surface tension on the fluctuation spectrum is largely eliminated by the pressure resulting from the mixing entropy of the adhesion bonds.