Pathways connecting two opposed bilayers with a fusion pore: A molecularly-informed phase field approach

TL;DR

This paper introduces a molecularly-informed phase field model to simulate self-assembled amphiphilic structures and membrane fusion pathways, revealing multiple fusion mechanisms and providing insights into membrane dynamics.

Contribution

It develops a novel phase field model based on the Ohta-Kawasaki extension to simulate membrane fusion pathways with multiple possible routes.

Findings

The model reproduces bilayers, vesicles, and micelles.

Multiple fusion pathways identified, including classical and leaky.

Model provides insights into membrane fusion mechanisms.

Abstract

A phase field model with two phase fields, representing the concentration and the head-tail separation of amphiphilic molecules, respectively, has been constructed using an extension of the Ohta-Kawasaki model (Macromolecules 19, 2621-2632 (1986)). It is shown that this molecularly-informed phase field model is capable of producing various self-assembled amphiphilic aggregates, such as bilayers, vesicles and micelles. Furthermore, pathways connecting two opposed bilayers with a fusion pore are obtained by using a combination of the phase field model and the string method. Multiple fusion pathways, including a classical pathway and a leaky pathway, have been obtained depending on the initial separation of the two bilayers. The study shed light to the understanding of membrane fusion pathways and, more importantly, laid a foundation for further investigation of more complex membrane morphologies and transitions.