Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
J Colloid Interface Sci. 2011 Dec 1;364(1):92-9. doi: 10.1016/j.jcis.2011.08.028. Epub 2011 Aug 19.
Comicellization of a star block copolymer poly(ε-caprolactone)-block-poly(diethylamino)ethyl methacrylate (S(PCL-b-PDEAEMA)) and a linear block copolymer methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-b-PCL) was developed to enhance the stability and lower the cytotoxicity of the micelles. The two copolymers self-assembled into the mixed micelles with a common PCL core surrounded by a mixed PDEAEMA/mPEG shell in aqueous solution. This core-shell structure was transformed to the core-shell-corona structure at high pH due to the collapse of the PDEAEMA segment. The properties of the polymeric micelles were greatly dependent on the weight ratio of the two copolymers and the external pH. As increasing the mPEG-b-PCL content, the size and the zeta potential of the mixed micelles were lowered while the pH-dependent stability and the biocompatibility were improved. Moreover, an increase in pH accelerated the release of indomethacin (IND) from the mixed micelles in vitro. These results augured that the mixed micelles could be applied as a stable pH-sensitive release system.
星型嵌段共聚物聚（ε-己内酯）-嵌段-聚（二乙氨基）乙基甲基丙烯酸酯（S（PCL-b-PDEAEMA））和线性嵌段共聚物甲氧基聚（乙二醇）-嵌段-聚（ε-己内酯）（mPEG-b-PCL）的胶束化被开发出来以提高胶束的稳定性和降低其细胞毒性。两种共聚物在水溶液中自组装成具有共同 PCL 核的混合胶束，由混合的 PDEAEMA/mPEG 壳包围。由于 PDEAEMA 段的塌陷，这种核壳结构在高 pH 值下转变为核壳-冠层结构。聚合物胶束的性质极大地依赖于两种共聚物的重量比和外部 pH 值。随着 mPEG-b-PCL 含量的增加，混合胶束的粒径和zeta 电位降低，而 pH 依赖性稳定性和生物相容性得到改善。此外，pH 值的升高加速了吲哚美辛（IND）从混合胶束中的体外释放。这些结果表明，混合胶束可用作稳定的 pH 敏感释放系统。
