Liquid demixing in elastic networks: Cavitation, permeation, or size selection?

¹ Aix Marseille Univ, CNRS, CINAM, Turing Center for Living Systems - Marseille, France
² Center for the Physics of Biological Function, Princeton University - Princeton, NJ 08544, USA
³ Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University Beijing 100871, PRC
⁴ Department of Mechanical and Aerospace Engineering, Princeton University - Princeton, NJ 08544, USA
⁵ Princeton Institute of Materials, Princeton University - Princeton, NJ 08544, USA

^(a) pierre.ronceray@univ-amu.fr
^(b) mhaataja@princeton.edu (corresponding author)

Received: 17 July 2021
Accepted: 18 February 2022

Abstract

In cells, phase-separated liquid condensates interact mechanically with surrounding elastic networks such as chromatin and cytoskeleton. By considering the trade-offs between elastic, wetting, and interfacial energies, we theoretically show that three droplet phases can be thermodynamically stable: macroscopic droplets that either cavitate or permeate the network, and mesh-size–limited microdroplets. We show that network strain stiffening further enhances this latter size-limitation effect. Our theory predicts the possibility of yet-unobserved droplet phases in the cytoplasm and nucleoplasm.