Abstract

The physics of biomolecular condensates provides a plethora of functionalities to living cells, including fluctuation buffering, selection and regulation of chemical reactions, and switch-like transitions of the condensate composition. In the presence of membrane surfaces, biomolecular condensates exhibit an even richer functionality by exploiting surface phase transitions, including wetting, prewetting, and surface phase separation. In contrast to the wetting of water drops on plant leaves, cellular surfaces are membranes with rich physico-chemical properties that include the active binding of condensate molecules into the membrane. Using theory, we show that active membrane binding and the physics of phase separation significantly alter the kinetics of wetting, leading to non-equilibrium steady states with condensate shapes reminiscent of a fried egg or a mushroom.