Date: 13 December, 2024
Speaker: Prof. Frank Jülicher
Living matter is highly dynamic and organizes in complex patterns and spatial morphologies. Such dynamics emerge because cells and tissues are driven far from thermodynamic equilibrium by a supply of chemical energy via metabolic processes. I will discuss the role of active processes in cell biophysics and present general concepts from irreversible thermodynamics that capture their physics. Fluid flows in cells are generated by material contractions that are driven by active mechanical stresses. They play a key role in the establishment of cell polarity. Phase-separated droplets form small compartments in cells that can organize biochemistry. Such biological condensates motivate the physical study of chemically active droplets that exhibit nonequilibrium states and that can imitate cell-like behaviors such as spontaneous division. Active droplets can also serve as simple physical models of protocells that operate away from equilibrium. Finally, at larger scales, many cells organize collectively during the morphogenesis of organisms. These examples show that living matter is a form of active matter governed by nonequilibrium physics. To unravel the principles that underlie the emergence of complex biological structures far from thermodynamic equilibrium will remain a challenge for future research.