Self-assembly and pH-Responsive Properties of Poly(L-glutamic acid-r-Lleucine) and Poly(L-glutamic acid-r-L-leucine)-b-Polysarcosine  

作　　者：Ce Tian 凌君 You-qing Shen 

机构地区：[1]MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Department of Polymer Science and Engineering,Zhejiang University [2]Department of Chemical and Biological Engineering,Zhejiang University

出　　处：《Chinese Journal of Polymer Science》2015年第8期1186-1195,共10页高分子科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.21174122 and 51390481)

摘　　要：Polypeptides and polypeptoids were widely used as biomedical materials because of their good biocompatibility. In this work we reported a series of pH-responsive copolypeptides and polypeptide-polypeptoid block copolymers, i.e. random copolymers of L-glutamic acid （Glu） with L-leucine （Leu） [poly（Glu-r-Leu）s], as well as their block copolymers with polysarcosine （polySar）. Well-defined poly（Glu-r-Leu）s with predictable compositions and molecular weights were synthesized by ring opening polymerization of corresponding N-carboxyanhydride monomers. We investigated the relationship between hydrophilicity-hydrophobicity transition and copolymer composition. With increasing Leu fraction, both the pH value of cloud point and the micellar size increased. Poly（Glu-r-Leu） with 60% Leu exhibited a cloud point at the pH of 5.0 to 6.0 the same as that in endosome and lysosome. Poly（Glu-r-Leu）-b-polySars assembled in phosphate buffer and performed pH-responsive morphology change from orbicular micelles at high pH to worm-like micelles at low pH. They were potential pH-responsive carriers for drug and gene delivery to enhance cargo release in cellules.Polypeptides and polypeptoids were widely used as biomedical materials because of their good biocompatibility. In this work we reported a series of pH-responsive copolypeptides and polypeptide-polypeptoid block copolymers, i.e. random copolymers of L-glutamic acid （Glu） with L-leucine （Leu） [poly（Glu-r-Leu）s], as well as their block copolymers with polysarcosine （polySar）. Well-defined poly（Glu-r-Leu）s with predictable compositions and molecular weights were synthesized by ring opening polymerization of corresponding N-carboxyanhydride monomers. We investigated the relationship between hydrophilicity-hydrophobicity transition and copolymer composition. With increasing Leu fraction, both the pH value of cloud point and the micellar size increased. Poly（Glu-r-Leu） with 60% Leu exhibited a cloud point at the pH of 5.0 to 6.0 the same as that in endosome and lysosome. Poly（Glu-r-Leu）-b-polySars assembled in phosphate buffer and performed pH-responsive morphology change from orbicular micelles at high pH to worm-like micelles at low pH. They were potential pH-responsive carriers for drug and gene delivery to enhance cargo release in cellules.

关 键 词：α-Amino acid NCA Random/block copolypeptide PH-RESPONSIVE Hydrophilicity-hydrophobicity transition. 

分 类 号：O636[理学—高分子化学] TQ460.1[理学—化学]