Specific Adhesion of Membranes: Mapping to an Effective Bond Lattice Gas

TL;DR

This paper models the specific adhesion of fluctuating membranes to substrates as a lattice gas, deriving effective interactions from membrane undulations and validating the model with kinetic Monte Carlo simulations.

Contribution

It introduces a lattice gas model for membrane adhesion, explicitly deriving effective bond interactions from membrane fluctuations and validating it against full dynamic simulations.

Findings

Lattice gas model accurately captures membrane adhesion behavior.

Derived effective bond interactions from membrane undulations.

Good agreement between simplified model and full dynamic simulations.

Abstract

We theoretically consider specific adhesion of a fluctuating membrane to a hard substrate via the formation of bonds between receptors attached to the substrate and ligands in the membrane. By integrating out the degrees of freedom of the membrane shape, we show that in the biologically relevant limit specific adhesion is well described by a lattice gas model, where lattice sites correspond to bond sites. We derive an explicit expression for the effective bond interactions induced by the thermal undulations of the membrane. Furthermore, we compare kinetic Monte Carlo simulations for our lattice gas model with full dynamic simulations that take into account both the shape fluctuations of the membrane and reactions between receptors and ligands at bond sites. We demonstrate that an appropriate mapping of the height dependent binding and unbinding rates in the full scheme to rates in the lattice gas model leads to good agreement.