Geometrical and thermodynamical considerations about the lipid vesicles formation in water (II. Multilamellar vesicles)

This is the second part of the work where a parametrization based on the differential geometry and on the thermodynamics of dispersed systems is developed, in order to approach the phospholipid vesicles formation in water. Several factors of known importance such as aqueous interlayer, chain-length, lipid-chain packing and membrane asymmetry, as well as the different surfaces in the vesicular bilayer are considered. The energy barrier which amphiphile molecules needs to surmount in order the liposome be formed is defined by the surface energy, the mechanical energy due to Laplaceʹs overpressure and the excess of chemical potential. The theoretical results define the conditions at which multilamellar vesicles are formed. Several bases are also established about the stability and evolution of multilamellar vesicles. This parametrization is applied to the phospholipids: dilauryl-, dimyristoyl-, dipalmytoyl-, and distearoyl-phosphatidylcholine.