| 초록 |
Glucose-sensitive dipalmitoyl phosphatidycholine liposomal bilayers were prepared by modifying the surface of liposomes with copolymer of NIPAM, methacrylic acid (MAA) and octadecylacrylate (ODA) (P(NIPAM-co-MAA-co-ODA)) and hydrophobically modified glucose oxidase (hGOd). MAA residue acts as a pH-sensitive moiety and octadecylacrylate as a hydrophobic anchor. At neutral and alkali conditions, carboxyl groups of MAA residues are ionized and copolymer chains would take an expanded form. As a result, the liposomes were stable in terms of release. When glucose was added to the liposomal suspension, the liposomal suspension became acidic. This is because that the enzymatic reaction of GOD with glucose produces gluconic acid. In this circumstance, carboxyl groups of MAA are unionized and the copolymer could take a contracted form. Hence, the liposmal membrane could be disintegrated by the contraction of copolymers. In fact, the liposomes exhibited a marked release, when glucose was added. |
