Photochemical control on morphologies of a cell-sized synthetic vesicle

By using a synthetic photosensitive amphiphile containing azobenzene (KAON12), we developed a method for the photo-manipulation of lipid membrane morphology, in which the shape of a vesicle can be switched by light. Cell-sized liposomes are prepared from KAON12 and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We conducted real-time observations of vesicular transformation in the photo-sensitive liposome by phase-contrast microscopy, and found that membrane budding transitions could be controlled by light. These transformations can be interpreted in terms of the change in the effective membrane surface area due to photoisomerization of the constituent molecules. We discuss the mechanism by considering the elastic free energy of the membranes.