A Novel Type of Membranes Based on Cholesteryl Phosphate

Mixtures of the rigid amphiphile disodium cholesteryl phosphate (DCP) with the non-phosphorylated diacyl amphiphile dimyristoylglycerol (DMG) give self-organized systems in a wide range of pH, as demonstrated by differential microcalorimetry. These systems can be closed bilayer vesicles, as shown by optical microscopy (Nomarski and confocal). Neither DMG nor DCP, taken alone, give vesicles in these conditions but 10% DMG is enough to lead to the formation of vesicles from pH 5.8 to 9.3. These novel self-organized systems are akin to the classical eucaryotic ones, built on a phosphorylated diacylglycerol and free cholesterol (or analogues), the only difference being the site of the phosphate head-group.