Regensburg 2022 – scientific programme
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BP: Fachverband Biologische Physik
BP 17: Membranes and Vesicles
BP 17.2: Talk
Wednesday, September 7, 2022, 15:15–15:30, H13
SAXS measurements of photoswitching in azobenzene lipid vesicles — Martina Ober1, Adrian Müller-Deku2, Oliver Thorn-Seshold2, and •Bert Nickel1 — 1Faculty of Physics and CeNS, Ludwig-Maximilians-Universiät München, Geschwister-Scholl-Platz 1, Munich 80539, Germany — 2Department of Pharmacy, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, Munich 81377, Germany,
We study the switching of photoresponsive lipids that allow for precise and reversible manipulation of membrane shape, permeability, and fluidity. Though these macroscopic responses are clear, it is unclear how large the changes of trans/cis ratio are, and whether they can be improved. Here, we use small-angle X-ray scattering to measure the thickness of photoswitchable lipid membranes, and we correlate lipid bilayer thickness to trans/cis ratios [1]. This reveals an unexpected dependency of photoswitching ratio upon aqueous phase composition. In buffer with ionic strength, we observe thickness variations twice as large as previously observed. Furthermore, soft X-rays can quantitatively isomerise photolipid membranes to the all-trans state; enabling X-ray-based membrane control. High energy X-rays do not influence the state of the photoswitches, presumably because they deposit less dose in the sample.
[1] M. Ober et al, Nanophotonics 2022; 11(10): 2361, DOI https://doi.org/10.1515/nanoph-2022-0053