Physics of droplet regulation in biological cells

Phase separation is crucial for partitioning the complex interior of biological cells. Phase separation leads to various droplets, known as biomolecular condensates, whose compositions are mainly controlled by genetically encoded interactions. These droplets need to form at the right time, at the right position, and with the right size to fulfill countless cellular functions. In my talk, I will discuss three crucial aspects affecting cellular phase separation. First, I will focus on multicomponent phase separation since cells comprise thousands of interacting components. Second, I will discuss the effects of elasticity in the droplets' surroundings, which affects their dynamics. Third, I will focus on driven chemical reactions, which allow controlling droplet nucleation, shape, and positioning. These examples demonstrate that studying phase separation in cells results in unique challenges because of the complex, active environment. While cells learned to exploit the respective physics over millennia to control their droplets, we are only starting to scratch the surface of this exciting interdisciplinary field.