Fluctuation-induced forces between inclusions in a fluid membrane under tension

TL;DR

This paper investigates how membrane tension influences fluctuation-induced Casimir forces between inclusions in fluid membranes, revealing that tension significantly alters force decay and could impact cellular protein interactions.

Contribution

It introduces a general method to calculate Casimir interactions considering combined membrane properties and highlights the tension's role in modifying force behavior.

Findings

Surface tension modifies the power law of the Casimir force.

Force is suppressed at large separations due to tension.

Potential implications for protein aggregation in membranes.

Abstract

We discuss the fluctuation-induced force, a finite-temperature analog of the Casimir force, between two inclusions embedded in a fluid membrane under tension. We suggest a method to calculate this Casimir interaction in the most general case, where membrane fluctuations are governed by the combined action of surface tension, bending modulus, and the Gaussian rigidity. We find that the surface tension strongly modifies the power law in the separation dependence of the Casimir interaction. This results in a strong suppression of the Casimir force at separations beyond a characteristic length, which could affect protein aggregation dynamics in cell membranes.