In-Situ spatiotemporal imaging of membrane hydration, electrostatics, tension and curvature to understand cell response to osmotic shocks and cell migration.
Lipid membranes compartmentalize and protect cells from the environment, and selectively permit transport. This functionality derives from unique membrane properties: 5 nm thick, yet fluid, deformable, resistant to stress and chemically complex. The physicochemical properties of membranes are expected to have a major impact on cell life, but the tools to measure the relevant multiscale and dynamic parameters in-vitro and, more importantly, in-vivo membranes are lacking. An essential property of membranes, their hydration and charge state, both needed for membrane integrity and playing a vital role in cell survival is not understood beyond the level of continuum theory. To enable quantitative physics, and physical chemistry for biology Roux and Roke, R^2, will join their expertise on molecular biology & biophysics and physics & interfacial chemistry & optics to create tools to measure membrane water and ion fluxes, and image 3D fields of electrostatic free energy, membrane tension and curvature. We will understand how molecular factors, such as the influence of the aqueous phase and interfacial electrostatics, are coupled to tension and curvature under dynamic conditions such as osmosis in artificial and cellular membranes. Obtaining the first temporally resolved, 3D maps of hydration, free energy, tension and curvature at the nanoscale in migrating cells and cells experiencing osmotic shocks we will quantify membrane physical parameters in two processes essential for cell survival, for which currently no data is available: Osmotic shock response and cell migration. Osmotic shock response plays an important role in infections, kidney and intestine function. Cell migration is essential to many cell processes, for example the spreading of cancer, wound repair and the immunological response, as well as food search in unicellular organisms.