An Ionic Polymer Bead-supported Lipid System Using Naturally Occurring Phospholipids

Spherically supported bilayer membranes on cationic polymer beads were prepared from naturally occurring phospholipids (phosphatidylcholine (PC) and phosphatidylserine (PS)). The amount of phospholipids bound to the cationic polymer beads from the liposomal suspensions of various lipid compositions increased with increases in anionic PS. Confocal fluorescence microscopic observations with a fluorescence membrane probe indicated that the phospholipid molecules in the phospholipid-bead complexes were along the surface of the beads. Negatively charged trypan blue dye was preferably bound to the phospholipid-free beads by electrostatic attractive interaction, but was excluded from the phospholipid-bead complexes due to the bilayer membrane structure formed on the beads. This method could provide a better mimetic of biological membranes in comparison to physically unstable conventional liposomes.