The remaining question is how intact immobilization and release can be achieved in this system. Our case stands in sharp contrast to the case for liposome interaction with solid surfaces. When liposome interacts with solid surface, the liposomes are typically ruptured and fused each other, finally resulting in the formation of lipid bilayer on the surface. We supposed electrostatic repulsion plays a critical role in maintaining the structures of anionic liposomes whereas it unfavorably works for their adsorption. In this context, Seifert and Lipowsky proposed a simple theory for stability of adsorbed liposomes on solid flat surface. The balance of attractive interaction and repulsion or curvature energy of the vesicles is determinant for the stability of liposomes. Hence, relative weak attraction would make contact energy so decreased that anionic liposomes would remain intact inside the AAO pore. On the other hand, we found that adsorption isotherm for neutral and cationic liposomes significantly differed from that for anionic ones (Figure ). Their isotherms feature the IUPAC II type isotherms, in which the adsorption is remarkably promoted when the liposome concentration is over the threshold. We consider that the behavior is associated with the formation of lipid bilayer after rupture or fusion of liposomes on the AAO pores. It is suggested that the scenarios of adsorbed liposomes are linked with vesicular coverage density on solid surface. When a critical coverage is reached, vesicles would interact neighboring others to rupture and/or fuse. Large amount of adsorption for neutral and cationic liposomes would cause solid-supported bilayer formation when surface vesicle coverage was over critical coverage. Actually, the release ratio of neutral and cationic liposomes could not be determined quantitatively due to the poor reproducibility. This may be ascribed that neutral and cationic liposomes are unstable inside AAO pores. While further studies are needed, these findings should contribute to the understanding the unique environments that allow intact immobilization and release of anionic liposomes on AAO.