Rheology of sliding leaflets in coarse-grained DSPC lipid bilayers

TL;DR

This study uses coarse-grained simulations to analyze the friction and viscoelastic response of DSPC lipid bilayers under shear, revealing state-dependent mechanical behaviors.

Contribution

It provides new insights into the interleaflet friction and transient viscoelastic properties of DSPC bilayers through numerical simulations.

Findings

Friction coefficient varies with membrane state.

Linear viscoelastic response in fluid phase.

Nonlinear response in gel phase.

Abstract

Amphiphilic lipid bilayers modify the friction properties of the surfaces on top of which they are deposited. In particular, the measured sliding friction coefficient is significantly reduced compared with the native surface. We investigate in this work the friction properties of a numerical coarse-grained model of DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) lipid bilayer subject to longitudinal shear. The interleaflet friction coefficient is obtained from out-of-equilibrium pulling and relaxation simulations. In particular, we gain access to the transient viscoelastic response of a sheared bilayer. The bilayer mechanical response is found to depend significantly on the membrane physical state, with evidence in favor of a linear response regime in the fluid but not in the gel region.