Partitioning of Ganglioside-Reconstituted Liposomes in Aqueous Two-Phase Systems

The partitioning of ganglioside (GM ₃ ,GD _1a, GD _1b or GT _1b )-reconstituted liposomes was investigated in an aqueous poly(ethylene oxide)/dextran two-phase system to evaluate the carbohydrate–carbohydrate interactions in water. The partitioning of the ganglioside-reconstituted liposome was strongly affected by the buffer employed. As the concentration of sodium phosphate decreased, the ganglioside-reconstituted liposomes were partitioned to the bottom, dextran-rich, phase. In 10 mM sodium phosphate containing 150 mM sodium chloride, the conventional liposome without ganglioside were located mostly at the interface between the two phases. On the other hand, the ganglioside-reconstituted liposomes were significantly partitioned to the bottom dextran-rich phase, which was related to the ganglioside density on the liposomal surface. This partitioningto the dextran-rich phase also depended on the chemical structure of the ganglioside on the liposomal surface. The affinity of liposomal ganglioside being on the liposomal surface to dextran was the following sequence; GT _1b >GD _1a >GD _1b >GM ₃ . Partitioning of liposomes to the top poly(ethylene oxide)-rich phase was negligible irrespective of the characteristics of the liposomal surface.