Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands.
Phys Rev Lett. 2020 Oct 30;125(18):188002. doi: 10.1103/PhysRevLett.125.188002.
The Gaussian (saddle splay) rigidity of fluid membranes controls their equilibrium topology but is notoriously difficult to measure. In lipid mixtures, typical of living cells, linear interfaces separate liquid ordered (LO) from liquid disordered (LD) bilayer phases at subcritical temperatures. Here, we consider such membranes supported by curved substrates that thereby control the membrane curvatures. We show how spectral analysis of the fluctuations of the LO-LD interface provides a novel way of measuring the difference in Gaussian rigidity between the two phases. We provide a number of conditions for such interface fluctuations to be both experimentally measurable and sufficiently sensitive to the value of the Gaussian rigidity, while remaining in the perturbative regime of our analysis.
流体膜的高斯（鞍形伸展）刚性控制着它们的平衡拓扑结构，但却很难测量。在典型的活细胞的脂质混合物中，线性界面将有序液体（LO）与无序液体（LD）双层相在亚临界温度下分隔开。在这里，我们考虑由弯曲基底支撑的这种膜，从而控制膜的曲率。我们展示了如何通过对 LO-LD 界面的涨落进行谱分析，提供一种测量两相之间高斯刚性差异的新方法。我们提供了一些条件，使得这种界面涨落既具有实验可测量性，又对高斯刚性值具有足够的敏感性，同时仍然处于我们分析的微扰范围内。
