Evolution of the thermotropic properties of large unilamellar vesicles (LUV)

The evolution of the thermotropic properties of large unilamellar vesicles (LUV) made by the reverse-phase evaporation technique has been studied by differential scanning calorimetry (DSC) and by fluorescence polarization of the diphenylhexatriene probe inserted in the lipid phase. Lipid fluidity and transition temperatures of DL-alpha-dimyristoyl-and DL-alpha-dipalmitoyl-phosphatidylcholine vesicles were practically not modified at room temperature (19-20 degrees C), even after several days. Because a better knowledge of the physico-chemical properties of LUV seems essential for its use as a model membrane or as a carrier of exogenous material into cells, we compare it with the stability of the widely used multilamellar (MLV) and sonicated unilamellar vesicles (SUV).