Characterization and phase behaviour of phospholipid bilayers adsorbed on spherical polysaccharidic nanoparticles

In this paper a new drug carrier, the Light-biovector, is described. These biovectors are composed of a neutral, anionic or cationic polysaccharidic core surrounded by phospholipids. They can be prepared with high yield and in a nearly pure form as determined by density analysis on sucrose gradients. These particles showed great stability with no sedimentation being observed after more than one year of storage. Physicochemical studies carried out with dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol mixtures showed that in Light-biovectors, the lipids are organized in bilayer surrounding the polysaccharidic core. In presence of a neutral polysaccharidic core, the gel to liquid phase transition temperature Tm of DPPC was only slightly affected as compared to liposomal dispersions of the lipid. In contrast, for cationic and anionic Light-biovectors, the Tm of the lipids was affected by the electric charge born by the polysaccharidic core, indicating that electrostatic interactions contribute to the organization of the lipid bilayer in these systems. It was also found that the association of anionic membrane to anionic polysaccharidic cores and the association of cationic membrane to cationic polysaccharidic cores was possible.