Thermodynamic Approach to Phase Coexistence in Ternary Phospholipi-Cholesterol Mixtures

TL;DR

This paper presents a thermodynamic model for predicting phase coexistence in ternary phospholipid-cholesterol mixtures, accurately reproducing known phase diagrams and their temperature dependence.

Contribution

It introduces a simple, predictive Gibbs free-energy model based on lipid transition thermodynamics, enabling efficient computation of phase diagrams.

Findings

Reproduces known phase coexistence features at 10°C

Accurately models temperature evolution of phase diagrams

Provides a fast numerical approach for phase stability analysis

Abstract

We introduce a simple and predictive model for determining the phase stability of ternary phospholipid-cholesterol mixtures. Assuming that competition between the liquid and gel order of the phospholipids is the main driving force behind lipid segregation, we derive a Gibbs free-energy of mixing, based on the thermodynamic properties of the lipids main transition. A numerical approach was devised that enable the fast and efficient determination of the ternary diagrams associated with our Gibbs free-energy. The computed phase coexistence diagram of DOPC/DPPC/cholesterol reproduces well known features for this system at 10\circ C, as well as its evolution with temperature.