Pore formation in fluctuating membranes

TL;DR

This paper investigates how membrane fluctuations influence pore formation in lipid membranes, revealing new regimes where entropy stabilizes pores at high temperatures.

Contribution

It introduces a framework that accounts for membrane and pore shape fluctuations, identifying novel low-tension regimes with entropy-driven pore stability.

Findings

Large pores' nucleation free energy depends on effective surface and line tensions.

Discovery of a low-tension regime where effective tensions change sign.

High-temperature conditions favor stable pore formation due to entropy.

Abstract

We study the nucleation of a single pore in a fluctuating lipid membrane, specifically taking into account the membrane fluctuations, as well as the shape fluctuations of the pore. For large enough pores, the nucleation free energy is well-described by shifts in the effective membrane surface tension and the pore line tension. Using our framework, we derive the stability criteria for the various pore formation regimes. In addition to the well-known large-tension regime from the classical nucleation theory of pores, we also find a low-tension regime in which the effective line and surface tensions can change sign from their bare values. The latter scenario takes place at sufficiently high temperatures, where the opening of a stable pore of finite size is entropically favorable.