Accurate determination of elastic parameters for multi-component membranes

TL;DR

This paper introduces an integrated analytical and experimental method to accurately measure the elastic properties of phase-separated vesicles, providing insights into membrane nanodomain stability in cells.

Contribution

It presents a novel combined approach for determining membrane parameters in multiphase vesicles, linking shape analysis with fluctuation data.

Findings

Reliable measurement of line tension and bending moduli.

Determines size and stability limits of nanodomains.

Enhances understanding of membrane heterogeneity effects.

Abstract

Heterogeneities in the cell membrane due to coexisting lipid phases have been conjectured to play a major functional role in cell signaling and membrane trafficking. Thereby the material properties of multiphase systems, such as the line tension and the bending moduli, are crucially involved in the kinetics and the asymptotic behavior of phase separation. In this Letter we present a combined analytical and experimental approach to determine the properties of phase-separated vesicle systems. First we develop an analytical model for the vesicle shape of weakly budded biphasic vesicles. Subsequently experimental data on vesicle shape and membrane fluctuations are taken and compared to the model. The combined approach allows for a reproducible and reliable determination of the physical parameters of complex vesicle systems. The parameters obtained set limits for the size and stability of nanodomains in the plasma membrane of living cells.