Tian Huayu, Chen Xuesi, Lin Hao, Deng Chao, Zhang Peibiao, Wei Yen, Jing Xiabin
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, China.
Chemistry. 2006 May 24;12(16):4305-12. doi: 10.1002/chem.200501322.
A novel, hyperbranched, amphiphilic multiarm biodegradable polyethylenimine-poly(gamma-benzyl-L-glutamate) (PEI-PBLG) copolymer was prepared by the ring-opening polymerization of gamma-benzyl-L-glutamate-N-carboxyanhydride (BLG-NCA) with hyperbranched PEI as a macroinitiator. The copolymer could self-assemble into core-shell micelles in aqueous solution with highly hydrophobic micelle cores. As the PBLG content was increased, the size of the micelles increased and the critical micelle concentration (CMC) decreased. The surface of the micelles had a positive zeta potential. The cationic micelles were capable of complexing with plasmid DNA (pDNA), which could be released subsequently by treatment with polyanions. The PEI-PBLG copolymer formed unimolecular micelles in chloroform solution. The pH-sensitive phase-transfer behavior exhibited two critical pH points for triggering the encapsulation and release of guest molecules. Both the encapsulation and release processes were rapid and reversible. Under strong acidic or alkaline conditions, the release process became partially or completely irreversible. Thus, this copolymer system should be an attractive candidate for a gene- or drug-delivery system in aqueous media and could provide the phase-transfer carriers between water and organic media.
以超支化聚乙烯亚胺（PEI）为大分子引发剂，通过γ-苄基-L-谷氨酸-N-羧酸酐（BLG-NCA）的开环聚合反应制备了一种新型的超支化两亲性多臂可生物降解聚乙烯亚胺-聚（γ-苄基-L-谷氨酸）（PEI-PBLG）共聚物。该共聚物在水溶液中可自组装成具有高度疏水胶束核的核壳胶束。随着PBLG含量的增加，胶束尺寸增大，临界胶束浓度（CMC）降低。胶束表面具有正的zeta电位。阳离子胶束能够与质粒DNA（pDNA）复合，随后通过用聚阴离子处理可释放pDNA。PEI-PBLG共聚物在氯仿溶液中形成单分子胶束。pH敏感的相转移行为表现出两个触发客体分子包封和释放的临界pH点。包封和释放过程均快速且可逆。在强酸性或碱性条件下，释放过程部分或完全不可逆。因此，该共聚物体系应是水性介质中基因或药物递送系统的有吸引力的候选者，并可为水相和有机相之间提供相转移载体。
