A water window on biochemistry & physics: membranes, ions, ion channels, and neuronal activity
| Dates: | 17 February 2021 |
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| Times: | 13:00 - 14:00 |
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| What is it: | Seminar |
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| Organiser: | Photon Science Institute |
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| Who is it for: | University staff, Current University students |
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| Speaker: | Professor Sylvie Roke |
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Join us for this PSI seminar with guest speaker Professor Sylvie Roke. Lipid cell membranes are essential for life: They are a dynamic compartmentalized environment, a localized space for proteins to perform their functions, and select what enters the cell. Although recognized as an essential building block, water is usually treated as a background for biology. However, water is a crucial mediator of chemical change and determines the structure of the membrane. The study of lipid membranes is generally pursued by following either a top-down approach, introducing labels to living cell membranes or a bottom-up approach with well-controlled but over-simplified membrane monolayer or supported membrane models. In the first approach molecular level hydration information is lost, while in the second approach the connection with real bilayer membranes is limited. Recent work in our laboratory offers an alternative path that ultimately envisions bringing together both top-down and bottom-up approaches. By using intermediate nano-, micro- and macroscale freefloating membrane systems in combination with novel nonlinear optical spectroscopy and imaging methods, we advance the understanding of realistic membranes on a more fundamental level, yet allowing for the complexity of living systems. In this presentation I will first introduce high throughput wide-field second harmonic imaging, which enables the label-free imaging of interfacial (< 1 nm thick) water, with a spatial resolution of ~370 nm and using ~100 ms acquisition times per image. We obtain information about the orientational order of water and use this interfacial response to create spatiotemporal membrane potential maps of free standing lipid membranes in solution. These maps are then used to quantify divalent – membrane interactions, which show surprisingly heterogeneous behavior that deviates from predictions by mean field. Finally, I will show how water in operating ion channels can be SH imaged and understood, and how this can be used to directly visualize neuronal activity in brain cells.
This event will be taking place online and details on how to join will be made available shortly.
Speaker
Professor Sylvie Roke
Organisation: Swiss Federal Institute of Technology in Lausanne
Biography: Sylvie Roke is a full professor at EPFL. She obtained master degrees in chemistry (2000) and physics (2000) from Utrecht University (NL) with highest honors, and then obtained a PhD degree (2004, highest honors) from Leiden University with A.W. Kleyn and M. Bonn. She was Max-Planck free floating Group Leader at the MPI for Metals Research in Stuttgart (2006-2012), and became director of the Laboratory for fundamental BioPhotonics at EPFL in 2011, where she holds the Julia Jacobi chair in photomedicine. Her work focuses on developing new optical tools and theories for gaining molecular level insight into aqueous systems and interfaces. She applies them to understand water, aqueous solutions, 3D-realistic interfaces and biological systems.
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This event will take place online
