(318g) Osmotically-Activated Membrane Biointerfaces

The physical properties of membranes are now largely well-understood at thermodynamic equilibrium. But generic descriptions of far-from-equilibrium behaviors of membranes – which allow living cells to sense, respond, and adapt to environmental perturbations while displaying extraordinary stability – are conspicuously lacking. Here, non-equilibrium activities of membrane-proteins, underlying cytoskeleton, and osmotic activities of water bathing the membrane, all couple with membrane’s physical, chemical, and mechanical degrees of freedom producing long-lived out-of-equilibrium structures with emergent reconfigurable morphologies and cooperative behaviors.
Drawing from recent experiments in our labs employing giant vesicles, this talk considers how the osmotic activity of water is transduced across cell-like compartments. It highlights how water activity and accompanying dissipation of osmotic energy can (1) induce intravesicular liquid-liquid phase separation; (2) couple with the compartmental boundary, mechanically remodeling the membrane shape and redistributing membrane domains; and (3) facilitate solute uptake through mechanical folding and scission reminiscent of endocytosis.