title: Doxorubicin-loaded aromatic imine-contained amphiphilic branched star polymer micelles: synthesis, self-assembly, and drug delivery.
abstract: Redox-and pH-sensitive branched star polymers (BSPs), BP(DMAEMA-co-MAEBA-co-DTDMA)(PMAIGP)(n)s, have been successively prepared by two steps of reversible addition-fragmentation chain transfer (RAFT) polymerization. The first step is RAFT polymerization of 2-(N,N-dimethylaminoethyl)methacrylate (DMAEMA) and p-(methacryloxyethoxy) benzaldehyde (MAEBA) in the presence of divinyl monomer, 2,2'-dithiodiethoxyl dimethacrylate (DTDMA). The resultant branched polymers were used as a macro-RAFT agent in the subsequent RAFT polymerization. After hydrolysis of the BSPs to form BP(DMAEMA-co-MAEBA-co-DTDMA)(PMAGP)(n)s (BSP-H), the anticancer drug doxorubicin (DOX) was covalently linked to branched polymer chains by reaction of primary amine of DOX and aldehyde groups in the polymer chains. Their compositions, structures, molecular weights, and molecular weight distributions were respectively characterized by nuclear magnetic resonance spectra and gel permeation chromatography measurements. The DOX-loaded micelles were fabricated by self-assembly of DOX-containing BSPs in water, which were characterized by transmission electron microscopy and dynamic light scattering. Aromatic imine linkage is stable in neutral water, but is acid-labile; controlled release of DOX from the BSP-H-DOX micelles was realized at pH values of 5 and 6, and at higher acidic solution, fast release of DOX was observed. In vitro cytotoxicity experiment results revealed low cytotoxicity of the BSPs and release of DOX from micelles in HepG2 and HeLa cells. Confocal laser fluorescence microscopy observations showed that DOX-loaded micelles have specific interaction with HepG2 cells. Thus, this type of BSP micelle is an efficient drug delivery system.
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Hong
authors.affiliation: Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
authors.forename: Cai-Yuan
authors.initials: CY
authors.lastname: Pan
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000737:chemistry; D001547:Benzaldehydes / Q000737:chemistry; D002850:Chromatography, Gel; D004317:Doxorubicin / Q000008:administration & dosage* / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods*; D006367:HeLa Cells / Q000187:drug effects; D056945:Hep G2 Cells / Q000187:drug effects; D006801:Humans; D006868:Hydrolysis; D007097:Imines / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000737:chemistry; D008823:Micelles; D008970:Molecular Weight; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D001547:Benzaldehydes; D007097:Imines; D008689:Methacrylates; D008823:Micelles; D011108:Polymers; D004317:Doxorubicin; C049840:2-(dimethylamino)ethyl methacrylate
keywords: RAFT polymerization; branched star polymer; controlled release; doxorubicin; pH-sensitive