Review on the "Physics of droplet regulation in biological cells"

We wrote a review on the "Physics of droplet regulation in biological cells", which is currently available at arxiv.org/abs/2501.13639. Beside the basic physics of phase separation, we discuss three aspects that separate cellular droplets from traditional ones: First, condensates comprise many different biomolecules, which are diverse and individually complex. This implies that cellular droplets posses complex internal behavior, e.g., in terms of their material properties. Second, the cellular environment contains many solid-like structures, like the cytoskeleton, and softer structures, like membranes. Condensates interact with those structures by wetting, which affects their shape, size, and location. Third, cells are alive and use fuel to drive processes out of equilibrium. In particular, they can modify the physical interactions of molecules against the thermodynamic tendency. The resulting active matter can exhibit controlled nucleation, shape deformations, and even division. Taken together, these physical processes allow cells to control droplets, and vice versa.

We started thinking about this review more than 3.5 years ago (thanks to Estefania and Jan!) and updated the draft continuously. We hope that the text now reveals useful links between the biology and soft matter literature. We also hope that it is useful for people who want to study condensates theoretically!

Physical phenomena relevant to intracellular droplets discussed in this review