Analytical derivation of thermodynamic properties of bolalipid membrane

TL;DR

This paper analytically models a bilayer membrane with bola-lipids, revealing significant differences in thermodynamic properties and pressure profiles compared to regular membranes without linked chains.

Contribution

It introduces an analytical model for bola-lipid membranes with linked tails, highlighting key thermodynamic differences from traditional membranes.

Findings

Lateral pressure profile at the layer interface differs significantly.

The mid-plane pressure peak disappears in linked membranes.

Distribution of the orientational order parameter is altered.

Abstract

We consider a model of bilayer lipid membrane with bola-lipids. The bola-lipid is modeled by linking tails of the hydrophobic chains in the opposite monolayers within bilayer as a first approximation. A number of thermodynamical characteristics are calculated analytically and compared with the ones of a regular membrane without chains linkage. Pronounced difference between lateral pressure profiles at the layers interface for linked and regular bilayer models is found. In the linked case, the lateral pressure mid-plane peak disappears, while the free energy per chain increases. We have also calculated distribution of the orientaional order parameter of linked chains across the bilayer, and found it is in contrast with the usual lipids case.