A Lipid Photoswitch Controls Fluidity in Supported Bilayer Membranes

Urban, Patrick; Pritzl, Stefanie D.; Ober, Martina F.; Dirscherl, Christina F.; Pernpeintner, Carla; Konrad, David B.; Frank, James A.; Trauner, Dirk; Nickel, Bert und Lohmueller, Theobald (2020): A Lipid Photoswitch Controls Fluidity in Supported Bilayer Membranes. In: Langmuir, Vol. 36, No. 10: pp. 2629-2634

Abstract

Supported lipid bilayer (SLB) membranes are key elements to mimic membrane interfaces on a planar surface. Here, we demonstrate that azobenzene photolipids (azo-PC) form fluid, homogeneous SLBs. Diffusion properties of azo-PC within SLBs were probed by fluorescence microscopy and fluorescence recovery after photobleaching. At ambient conditions, we find that the trans-to-cis isomerization causes an increase of the diffusion constant by a factor of two. Simultaneous excitation with two wavelengths and variable intensities furthermore allows to adjust the diffusion constant D continuously. X-ray reflectometry and small-angle scattering measurements reveal that membrane photoisomerization results in a bilayer thickness reduction of similar to 0.4 nm (or 10%). While thermally induced back-switching is not observed, we find that the trans bilayer fluidity is increasing with higher temperatures. This change in diffusion constant is accompanied by a red-shift in the absorption spectra. Based on these results, we suggest that the reduced diffusivity of trans-azo-PC is controlled by intermolecular interactions that also give rise to H-aggregate formation in bilayer membranes.

• Item Type: Journal article
• Faculties: Physics
• Research Centers: Center for NanoScience (CENS)
• Subjects: 500 Science > 530 Physics; 500 Science > 500 Science
• ISSN: 0743-7463
• Language: English