具有可控质子化能力的阳离子聚合物的合成及表征

合成了聚乙二醇-聚赖氨酸嵌段共聚物(PEG-PLL),并利用Michael加成反应对其侧链进行叔胺和季铵化修饰,得到一系列具有支化胺结构和可控质子化能力的聚赖氨酸衍生物。通过核磁共振氢谱、傅里叶变换红外光谱和凝胶渗透色谱对聚合物的结构进行表征。利用pH滴定研究聚合物的质子化行为,发现季铵和叔胺修饰能够显著改变阳离子聚合物的质子缓冲能力,将pKa值从10.6分别降低至7.5和6.8。圆二色谱测试结果表明侧基修饰不仅使聚赖氨酸嵌段从无规卷曲构象变为含有α螺旋和β折叠的混合构象,而且能够调节其高级结构对肿瘤微环境的响应能力。

Synthesis and Characterization of Cationic Polymers with Controlled Protonation Capacity

A poly(ethylene glycol)-poly(L-lysine) (PEG-PLL) diblock copolymer was synthesized and decorated with quaternary ammonium and tertiary amine groups via Michael addition reaction.The cationic polymers were characterized by 1H-NMR,FT-IR and GPC.It is found that the buffer capacity of the cationic polymers is significantly varied,with pKa values changing from 10.6 to 7.5 and 6.8,respectively,after modification with quaternary ammonium and tertiary amine groups,as determined by pH titration.Furthermore,circular dichroism (CD) measurements reveal a transformation from a random coil structure to a mixed conformation containing both α-helical and β-sheet structures for these cationic polymers.In addition,the hierarchical structures could be further regulated in response to tumor microenvironments.