Nano-domain formation in charged membranes: Beyond Debye-Huckel approximation

TL;DR

This paper analytically studies microphase separation in charged membranes, revealing nano-domain formation beyond traditional Debye-Huckel approximations by explicitly considering electrostatic interactions and ion densities.

Contribution

It provides an analytical expression for the structure factor without Debye-Huckel approximation and predicts nano-domain formation in charged membranes.

Findings

Analytical structure factor with a peak at intermediate wave number

Prediction of nano-domains in charged membranes

Scale of nano-domains from several to tens of nanometers

Abstract

We investigate the microphase separation in a membrane composed of charged lipid, by taking into account explicitly the electrostatic potential and the ion densities in the surrounding solvent. While the overall (membrane and solvent) charge neutrality is assumed, the membrane can have a non-zero net charge. The static structure factor in the homogeneous state is analytically obtained without using the Debye-Huckel approximation and is found to have a peak at an intermediate wave number. For a binary membrane composed of anionic and neutral lipids, the characteristic wave number corresponds to a scale from several to tens of nanometers. Our numerical calculation further predicts the existence of nano-domains in charged membranes.