Tuning nucleation kinetics via nonequilibrium chemical reactions

TL;DR

This paper demonstrates how nonequilibrium chemical reactions can modify nucleation kinetics in phase separation, revealing new ways to control biomolecular condensate formation beyond equilibrium constraints.

Contribution

It introduces a framework for understanding how inhomogeneous chemical reactions influence nucleation kinetics, including the concept of a nonequilibrium interfacial tension.

Findings

Chemical reactions can accelerate nucleation without altering energetics.

Nucleation kinetics can be tuned independently of supersaturation.

Classical nucleation theory can be extended to nonequilibrium systems.

Abstract

Unlike fluids at thermal equilibrium, biomolecular mixtures in living systems can sustain nonequilibrium steady states, in which active processes modify the conformational states of the constituent molecules. Despite qualitative similarities between liquid--liquid phase separation in these systems, the extent to which the phase-separation kinetics differ remains unclear. Here we show that inhomogeneous chemical reactions can alter the nucleation kinetics of liquid--liquid phase separation in a manner that is consistent with classical nucleation theory, but can only be rationalized by introducing a nonequilibrium interfacial tension. We identify conditions under which nucleation can be accelerated without changing the energetics or supersaturation, thus breaking the correlation between fast nucleation and strong driving forces that is typical of phase separation and self-assembly at thermal equilibrium.