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Accepted · first revision · record

Title: How cells control the size and number of condensates
Plain: Ordinary droplets merge, and large ones grow at the expense of small ones until one big drop remains. Cells keep many small condensates of controlled size, and which physics stops the merging is disputed.
Precise: Determine which mechanism arrests Ostwald ripening and coalescence of condensates in vivo: chemical reactions that produce and destroy droplet material (chemically active emulsions, steady radius set by reaction and diffusion rates), elastic resistance of the chromatin or cytoskeletal network, surfactant-like molecules, or slow coarsening kinetics. A decisive test measures the droplet size distribution and its response to changes in reaction rates and network stiffness.
Settled by: In vivo perturbation of reaction rates and network stiffness with measured size distributions that match one mechanism's predictions and exclude the others.
Kind: well-posed
Answer type: mechanism
References: (empty)
Literature status: contested
Status note: Theories of chemically active emulsions advanced in 2024 to 2026 (e.g., arXiv 2501.16299); direct in vivo discrimination between mechanisms is lacking.
Posed since: (empty)