Photoinduced Shape Changes of Giant Vesicles Comprising Phospholipids and Azobenzene-Containing Cationic Amphiphiles

For the development of new functional materials for various applications, such as drug or gene delivery and environmental remediation, the relationship between function and morphology has been considered an important aspect for controlling affinity to the targets. However, there are only a few reports on this relationship because the molecular strategy for the precise control of vesicle shape has been restricted. Herein, we report the photocontrol of vesicle shape using azobenzene-containing amphiphilic switches. The addition of the photoswitches to vesicles composed of phospholipids yielded non-spherical vesicles. They exhibited reversible deformation between a non-spherical and spherical shape in response to ultraviolet and visible light illumination, respectively. From the results of the 1H NMR analyses, fluorescence spectra of the environmentally responsive probes, and Π-A isotherm measurements, the reversible photoresponsivity can be attributed to the changes in the vesicular membrane structures caused by migration of the photoswitches between the aqueous phase and membrane through their photoisomerization.