温敏性聚（N-异丙基丙烯酰胺）-b-聚（L-谷氨酸）的合成与表征

Synthesis and Characterization of Temperature Sensitive Polymers

采用原子转移自由基聚合法(ATRP)与氨基酸酸酐(NCA)开环聚合法(ROP)制备两组聚合度不同的嵌段聚合物聚(N-异丙基丙烯酰胺)-b-聚(L-谷氨酸)(PNIPAM100-b-PLGA20、PNIPAM60-b-PLGA20),制备过程简单、分子量可控。用核磁共振氢谱(1HNMR)、红外光谱(IR)表征此聚合物的结构,凝胶渗透色谱(GPC)表征此聚合物的分子量。两组聚合物的低临界溶解温度(LCST)分别为36℃、37℃,更接近人体体温。聚合物在温度高于LCST、pH=7.4的水溶液中可自组装成球状胶束,具有温度敏感性。动态光散射(DLS)测试表明胶束粒径均在100 nm以下。聚合物胶束能有效负载阿霉素(DOX),药物缓慢释放长达72 h,在药物释放领域具有潜在应用。

Two groups of block polymers,poly(N-isopropylacrylamide)-b-poly(L-glutamic acid)(PNIPAM100-b-PBLG15,PNIPAM60-b-PBLG15),were successfully synthesized by atom transfer radical polymerization(ATRP)and ring opening polymerization of amino acid anhydride(ROP)with a new multifunctional initiator.The structures of polymers were characterized by nuclear magnetic resonance spectroscopy(1HNMR)and infrared spectroscopy(IR),and the molecular weights were showed by gel permeation chromatography(GPC).In addition,the low critical dissolution temperatures(LCST)of the two groups were 36℃and 37℃,respectively,which were closer to human body temperature.The polymers are temperature sensitive,which can self-assemble into spherical micelles with temperature higher than LCST,pH=7.4.Dynamic light scattering measurements show that their particle sizes are below 100 nm.Micelles can load doxorubicin(DOX)effectively and achieve slow release up to 72 h and are potential drug-loading materials.