Mutual recognition between polymerized liposomes. III. Association processes between avidin and biotin on polymerized liposome surfaces.

Association processes between avidin and biotin in various liposome systems were studied. By incorporating biotin onto the polymerized liposome surface, association processes with free avidin were largely decelerated. When the number of binding sites on the liposome surface was taken into account, the corrected association rate constant was 4.3% of the theoretical value for binary collision. The association rate constant between avidin- and biotin-carrying polymerized liposomes was much smaller than those for both the free avidin-free biotin system and the free avidin/biotin-liposome system, probably due to the repulsive hydration phenomenon. The results are discussed both in terms of our understanding of cell-cell recognition phenomena and for the development of drug delivery systems.