Spatiotemporal pattern formation of membranes induced by surface molecular binding/unbinding

TL;DR

This study uses meshless membrane simulations to explore how molecular binding and unbinding induce complex spatiotemporal patterns and phase behaviors in membranes under equilibrium and nonequilibrium conditions.

Contribution

It introduces a novel simulation approach to analyze membrane pattern formation driven by molecular binding dynamics and curvature effects, revealing new pattern types and dynamics.

Findings

Membranes exhibit spiral-wave and homogeneous-cycling modes at different binding rates.

Binding-induced curvature changes lead to microphase separation and complex patterns.

Nonequilibrium conditions produce moving biphasic domains and fluctuating patterns.

Abstract

Nonequilibrium membrane pattern formation is studied using meshless membrane simulation. We consider that molecules bind to either surface of a bilayer membrane and move to the opposite leaflet by flip--flop. When binding does not modify the membrane properties and the transfer rates among the three states are cyclically symmetric, the membrane exhibits spiral-wave and homogeneous-cycling modes at high and low binding rates, respectively, as in an off-lattice cyclic Potts model. When binding changes the membrane spontaneous curvature, these spatiotemporal dynamics are coupled with microphase separation. When two symmetric membrane surfaces are in thermal equilibrium, the membrane domains form 4.8.8 tiling patterns in addition to stripe and spot patterns. In nonequilibrium conditions, moving biphasic domains and time-irreversible fluctuating patterns appear. The domains move ballistically or diffusively depending on the conditions.