Calculation of the Phase Behavior of Lipids

TL;DR

This paper models the phase behavior of lipids using mean-field theory and conformational enumeration, providing insights into lipid self-assembly and phase transitions with qualitative experimental agreement.

Contribution

It introduces a novel model combining the Rotational Isomeric State framework with mean-field theory to study lipid phase behavior.

Findings

The model predicts the transition between lamellar and inverted-hexagonal phases.

Qualitative agreement with experimental phase behavior is achieved.

Lipid architecture significantly influences phase stability.

Abstract

The self-assembly of monoacyl lipids in solution is studied employing a model in which the lipid's hydrocarbon tail is described within the Rotational Isomeric State framework and is attached to a simple hydrophilic head. Mean-field theory is employed, and the necessary partition function of a single lipid is obtained via a partial enumeration over a large sample of molecular conformations. The influence of the lipid architecture on the transition between the lamellar and inverted-hexagonal phases is calculated, and qualitative agreement with experiment is found.