Non-ideal mixing of lipids: a molecular dynamics perspective

• DOI: 10.48550/arxiv.2408.14403
• Publication Date: 2025-02-12
• Authors: L. Berezovska; R. Kociurzynski; F. Thalmann
• Keywords: Chemical Physics (physics.chem-ph); Biological Physics (physics.bio-ph); Physics - Chemical Physics; Soft Condensed Matter (cond-mat.soft); FOS: Physical sciences; Physics - Biological Physics; Condensed Matter - Soft Condensed Matter

Lipid membranes have complex compositions, and modeling the thermodynamic properties of multi-component lipid systems remains a remote goal. In this work, we attempt to describe the thermodynamics of binary lipid mixtures by mapping coarse-grained molecular dynamics systems to two-dimensional simple fluid mixtures. By computing and analyzing the density fluctuations of this model lipid bilayer, we determine the numerical value of the quadratic coupling term appearing in a model of regular solutions for the dipalmitoylphosphatidylcholine–dilinoleoylphosphatidylcholine pair of lipids at three different compositions. Our methodology is general and discussed in detail.