Photolipid Isomerization in Multicomponent Lipid Membranes: Effects of Temperature and Charge

Photoswitchable lipids based on azobenzene offer efficient optical control over membrane properties, making them advanced molecular nanoagents for biomedical applications. However, many details regarding their photoswitching dynamics in complex lipid environments or under physiological temperatures are still poorly understood. Here, we investigate how temperature and membrane charge affect the mixing and photoswitching efficiency of the photolipid azo-PC in membrane assemblies. In giant unilamellar vesicles (GUVs), the presence of charge lowers the mixing temperature, while small liposomes reveal a striking temperature dependence in photoswitching dynamics and efficiency. These findings show that temperature plays a critical role in enabling more complete switching in lipid mixtures, underscoring the need to account for thermal effects and charge in lipid systems for biomedical applications.