Generic multicomponent mixtures are multistable

TL;DR

This paper demonstrates that multicomponent mixtures can support numerous coexisting droplets and metastable states, challenging previous stability predictions and providing insights into cellular condensate formation.

Contribution

It combines numerical simulations and analytical laws to show that increasing components enhances phase coexistence, revealing multistability in complex mixtures.

Findings

Number of coexisting phases increases with components

Homogeneous mixtures become more stable with more components

Cells may exploit multistability for independent condensate formation

Abstract

Liquid mixtures of many interacting components often exhibit numerous coexisting types of droplets. An exciting example is the cytosol of biological cells, where diverse droplets, called condensates, are essential for cellular function. However, how much their formation is constrained by thermodynamics is currently unclear. Linear stability analysis predicts that homogeneous mixtures become more robust to fluctuations as the number of components increases, suggesting that droplets do not form easily in multicomponent mixtures. In contrast, we show through numerical simulations and analytical scaling laws that the number of coexisting phases typically increases with the number of components in equilibrium. The combination of both results suggests that generic multicomponent mixtures can maintain many metastable states with various droplets, generalizing the nucleation-and-growth regime of binary mixtures. Our theory also indicates why cells exhibit much fewer condensates than components and how they could exploit multistability to independently form various condensates.