Coupling chemical reactions to membrane curvature: A photochemical morphology switch

Mie investigate the morphological response of giant phosphatidylcholine ves icles to a photochemical reaction taking place in the aqueous medium. We co ntrol the sign and magnitude of membrane curvature by inducing photoaquatio n of ferricyanide inside or outside the vesicle capsules. Curvature respons e is quantified via analysis of changes in vesicle shapes and in their ther mal fluctuation spectra. As an underlying mechanism for the light-induced c hange in membrane curvature, we propose asymmetric charging of the internal or external monolayers by ion adsorption. Our study provides a specific ex ample of a coupling between chemical reactions and interfacial geometry. Th e new photo-morphological effect may be used as a fast and reversible switc h of membrane curvature.