SAXS measurements of azobenzene lipid vesicles reveal buffer-dependent photoswitching and quantitative Z→E isomerisation by X-rays

Nanophotonics

Thorn-Seshold Oliver¹  Müller-Deku Adrian¹  Ober Martina F.²  Ajanović Benjamin²  Baptist Anna²  Nickel Bert²  Amenitsch Heinz³ 

[1] Department of Pharmacy, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, Munich81377, Germany;Faculty of Physics and CeNS, Ludwig-Maximilians-Universiät München, Geschwister-Scholl-Platz 1, Munich80539, Germany;Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9, Graz8010, Austria;

关键词: azobenzene;    high-energy x-ray;    isomerization;    lipid bilayer;    photoswitch;    saxs;   

DOI  :  10.1515/nanoph-2022-0053

来源: DOAJ

【 摘 要 】

Photoresponsive materials feature properties that can be adjusted by light near-instantaneously, reversibly, and with high spatiotemporal precision. There is considerable interest in maximising the degree of photoswitching, and in measuring this degree during illumination in complex environments. We study the switching of photoresponsive lipid membranes 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 used small-angle X-ray scattering to measure the thickness of photoswitchable lipid membranes, and we correlate lipid bilayer thickness to trans/cis ratios. 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.

【 授权许可】

Unknown