Theory of droplet ripening in stiffness gradients

Abstract

Liquid-liquid phase separation is an important mechanism for compartmentalizing the cell's cytoplasm, allowing the dynamic organization of the components necessary for survival. However, it is not clear how phase separation is affected by the complex viscoelastic environment inside the cell. Here, we study theoretically how stiffness gradients influence droplet growth and arrangement. We show that stiffness gradients imply concentration gradients in the dilute phase, which transport droplet material from stiff to soft regions. Consequently, droplets dissolve in the stiff region, creating a dissolution front. Using a mean-field theory, we predict that the front emerges where the curvature of the elasticity profile is large and that it propagates diffusively. This elastic ripening can occur at much faster rates than classical Ostwald ripening, thus driving the dynamics. Our work shows how gradients in elastic properties control the size and arrangement of droplets, which has potential applications in soft matter physics and plays a role inside biological cells.

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• Salt-dependent rheology and surface tension of protein condensates using optical traps
• Elastic ripening and inhibition of liquid-liquid phase separation
• Probing and manipulating embryogenesis via nanoscale thermometry and temperature control
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Cited by in corpus (6)

• Modelling Elastically-Mediated Liquid-Liquid Phase Separation
• Liquid demixing in elastic networks: cavitation, permeation, or size selection?
• Effect of Elasticity on Phase Separation in Heterogeneous Systems
• Cavitation controls droplet sizes in elastic media
• The intertwined physics of active chemical reactions and phase separation
• Controlling biomolecular condensates via chemical reactions