Dynamic Permeability in Metastable Droplet Interfacial Bilayers

TL;DR

This paper develops a theory linking transient pore growth mechanisms to size-selective transport in metastable droplet interfacial bilayers, providing insights into membrane permeability and structural dynamics.

Contribution

It introduces a mechanical model for pore growth dynamics and size distribution, enabling identification of dominant growth mechanisms and membrane properties.

Findings

Scaling relations between particle size, pore growth rate, and transport time.

Comparison of Ostwald ripening with other pore growth mechanisms.

Guidelines for experimental validation of the theoretical predictions.

Abstract

Membrane pores are implicated in several critical functions, including cell fusion and the transport of signaling molecules for intercellular communication. However, these structural features are often difficult to probe directly. Droplet interfacial bilayers offer a synthetic platform to study such membrane properties. We develop a theory that links size-selective transport across a metastable membrane with its transient structural properties. The central quantity of our theory is a dynamic permeability that depends on the mechanism of pore growth, which controls the transient distribution of pore sizes in the membrane. We present a mechanical perspective to derive pore growth dynamics and the resulting size distribution for growth \textit{via} Ostwald ripening and discuss how these dynamics compare to other growth mechanisms such as coalescence and growth through surfactant desorption. We find scaling relations between the transported particle size, the pore growth rate, and the time for a given fraction of particles to cross the membrane, from which one may deduce the dominant mechanism of pore growth, as well as material properties and structural features of the membrane. Finally, we suggest experiments using droplet interfacial bilayers to validate our theoretical predictions.