pH响应壳聚糖衍生物的合成与自组装

Synthesis and Self-assembly of pH-Sensitive Chitosan Amphiphilic Copolymers

以甲烷磺酸为反应溶剂,将己酰氯接枝到壳聚糖(CS)侧基上,得到可溶于常见有机溶剂的己酰化壳聚糖(HC);亲水性聚乙二醇单甲醚(mPEG)通过活泼酯法接枝到HC上,最终获得两亲性壳聚糖衍生物PEG-g-HC。用红外光谱(FT-IR)、核磁共振(1H-NMR)与紫外-可见光谱(UV-Vis)表征产物结构,用动态光散射、透射电镜与荧光光谱等方法研究了PEG-g-HC的自组装行为。结果表明:通过改变己酰氯与CS的投料比可调节HC的取代度;随着HC中己酰基取代度增大,HC在水介质中溶解的临界pH随之降低;PEG-g-HC可自组装为球形胶束,通过改变HC中己酰基的取代度可调控其pH响应行为。

Organo-soluble hexanoyl chitosan（HC） was synthesized through esterification reaction（between） chitosan and hexanoyl chloride in methylsulfonic acid solutions.This intermediate was further PEGylated through NHS-DCC coupling method to give PEG-g-HC.The chemical structure of HC and PEG-g-HC were characterized by FT-IR,^1H-NMR and UV-Vis.The self-assembly behavior of PEG-g-HC was （studied） by DLS,fluorometer and TEM.The degree of substitution（DS） of HC can be adjusted by varying the feed ratio of hexanoyl chloride to chitosan.The critical pH at which HC could be soluble in aqueous media increased with the increase of DS of HC.Spherical micelles with pH responsibility could be formed through self-assembling of PEG-g-HC in aqueous media.In addition,the critical pH where the（micelle） size abruptly decreased could also be modulated by varying the DS of HC.