Chemical reaction-controlled phase separated drops: Formation, size selection, and coarsening

TL;DR

This paper investigates how chemical reactions influence phase-separated droplet formation, size, and coarsening in a minimal model of cell cytoplasm, revealing regimes where ripening is arrested due to reaction rates.

Contribution

It introduces a minimal ternary fluid model with chemical reactions, analytically and via simulations, to understand non-equilibrium control of droplet behavior.

Findings

Drop size and formation are controllable by reaction rates.

Ostwald ripening can be arrested at high reaction rates.

Distinct regimes of phase behavior are categorized.

Abstract

Phase separation under non-equilibrium conditions is exploited by biological cells to organize their cytoplasm but remains poorly understood as a physical phenomenon. Here, we study a ternary fluid model in which phase-separating molecules can be converted into soluble molecules, and vice versa, via chemical reactions. We elucidate using analytical and simulation methods how drop size, formation, and coarsening can be controlled by the chemical reaction rates, and categorize the qualitative behavior of the system into distinct regimes. Ostwald ripening arrest occurs above critical reaction rates, demonstrating that this transition belongs entirely to the non-equilibrium regime. Our model is a minimal representation of the cell cytoplasm.