Interplay of curvature-induced micro- and nanodomain structures in multicomponent lipid bilayers

TL;DR

This paper presents a theoretical model exploring how curvature influences the formation and organization of micro- and nanodomains in multicomponent lipid bilayers, revealing complex phase behaviors and potential control mechanisms.

Contribution

The study introduces a coupled monolayer model with composition and curvature interactions, providing new insights into domain formation and organization in lipid membranes.

Findings

Complex phase diagrams with various phases and transitions

Discovery of a decorated microdomain phase with aligned nanodomains

External tension can control nanodomain organization

Abstract

We discuss different mechanisms for curvature-induced domain formation in multicomponent lipid membranes and present a theoretical model that allows us to study the interplay between the domains. The model represents the membrane by two coupled monolayers, which each carry an additional order parameter field describing the local lipid composition. The spontaneous curvature of each monolayer is coupled to the local composition, moreover, the lipid compositions on opposing monolayers are coupled to each other. Using this model, we calculate the phase behavior of the bilayer in mean-field approximation. The resulting phase diagrams are surprisingly complex and reveal a variety of phases and phase transitions, including a decorated microdomain phase where nanodomains are aligned along the microdomain boundaries. Our results suggest that external membrane tension can be used to control the lateral organization of nanodomains (which might be associated with lipid "rafts") in a multicomponent lipid bilayer.