Non-ideal mixing of lipids: a molecular dynamics perspective

TL;DR

This paper uses molecular dynamics simulations to analyze the thermodynamics of binary lipid mixtures, focusing on density fluctuations and coupling terms to better understand complex lipid membrane behaviors.

Contribution

It introduces a general methodology for mapping coarse-grained molecular dynamics systems to simple fluid mixtures to study lipid thermodynamics.

Findings

Determined the quadratic coupling term for DPPC-DLiPC at various compositions.

Analyzed density fluctuations to understand lipid mixture thermodynamics.

Provided a detailed discussion of the methodology's general applicability.

Abstract

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 analysing 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 DPPC-DLiPC pair of lipids at three different compositions. Our methodology is general and discussed in detail.