Domain Growth, Budding, and Fission in Phase Separating Self-Assembled Fluid Bilayers

TL;DR

This study investigates phase separation dynamics in self-assembled bilayer vesicles using large-scale simulations, revealing how composition asymmetry, hydrodynamics, and area-to-volume constraints influence morphological regimes.

Contribution

It provides a detailed numerical analysis of phase separation in bilayer membranes, highlighting the effects of hydrodynamics and geometric constraints on membrane morphology.

Findings

Asymmetric compositions lead to budding and vesiculation regimes.

Symmetric mixtures exhibit a growth exponent of 1/2.

Hydrodynamics and area-to-volume constraints significantly affect phase behavior.

Abstract

A systematic investigation of the phase separation dynamics in self-assembled multi-component bilayer fluid vesicles and open membranes is presented. We use large-scale dissipative particle dynamics to explicitly account for solvent, thereby allowing for numerical investigation of the effects of hydrodynamics and area-to-volume constraints. In the case of asymmetric lipid composition, we observed regimes corresponding to coalescence of flat patches, budding, vesiculation and coalescence of caps. The area-to-volume constraint and hydrodynamics have a strong influence on these regimes and the crossovers between them. In the case of symmetric mixtures, irrespective of the area-to-volume ratio, we observed a growth regime with an exponent of 1/2. The same exponent is also found in the case of open membranes with symmetric composition.