Séminaire GULLIVER

27 novembre 2023 11:30 » 12:30 — Charpak

Phase-Separated Droplets Swim to Their Dissolution

Cells control vital bio-chemical processes by creating compartments with distinct compositions. In addition to the well-known membrane-bound organelles, such as the nucleus or chloroplasts,
dynamic membraneless compartments formed through liquid-liquid phase separation have merged as important cellular constituents over the last decades. These biomolecular ondensates are liquid- like, their absence of membrane allow easy chemical exchanges with their surroundings, they can coalesce, exert capillary forces and dissolve or condense easily. While their formation and liquid-like properties are well established, much less is known on the effect of biochemical activity on them. In this talk, I will present our artificial chemically active biomolecular condensates based on Bovine Serum Albumin (BSA) rich droplets seeded with enzymes. I will show that the enzymatic activity can generate concentrations gradients that drives Marangoni swimming. Yet, only specific molecules trigger this Marangoni response in our surfactant free system. I will show that the surface tension variations emerge from local perturbations of the thermodynamic phase equilibrium and can be easily summarized as : phase-separated droplets swim to their dissolution.

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