基于聚氨基酸的线型-树状聚两性电解质的合成及pH响应性研究  

SYNTHESIS AND pH REVERSIBLE AGGREGATING BEHAVIOR OF POLY(AMINO ACID) BASED LINEAR-DENDRON-LIKE POLYAMPHOLYTE

作　　者：陈莉莉[1] 张帆[1] 陈涛[1] 陈叶[1] 林嘉平[1] 

机构地区：[1]华东理工大学材料科学与工程学院上海市先进聚合物材料重点实验室超细材料制备与应用教育部重点实验室,上海200237

出　　处：《高分子学报》2013年第2期270-278,共9页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20974032);中央高校基本科研业务费专项基金(基金号WD1114034)资助项目

摘　　要：采用开环聚合、发散法以及"点击化学法"合成了线型-树状聚两性电解质.首先通过γ-苄基-L-谷氨酸酯羧酸酐(BLG-NCA)的开环聚合及发散合成法分别合成了叠氮端基聚(γ-苄基-L-谷氨酸酯)(PBLG-N3)及以炔基为内核的带有4个伯氨端基的第2.0代聚酰胺-胺(PAMAM-D2),再将二者通过"点击反应"制备的线型-树状嵌段共聚物PBLG-b-D2作为大分子引发剂,利用其末端氨基引发ε-苄氧羰基-L-赖氨酸羧酸酐(ZLL-NCA)的开环聚合,获得线型-树状嵌段共聚物PBLG-b-D2-(PZLL)4,再经酸解脱除PBLG上的苄基及PZLL上的苄氧羰基,获得目标产物聚(L-谷氨酸)-b-聚[酰胺-胺-聚(L-赖氨酸)](PLGA50-b-D2-(PLL9)4)线型-树状聚两性电解质.通过核磁(1H-NMR)、傅里叶变换红外光谱(FTIR)和凝胶渗透色谱(GPC)表征了聚合物分子结构、分子量及其分布;通过电导滴定法、1H-NMR、zeta电位、激光光散射(LLS)、扫描电子显微镜(SEM)及圆二色谱(CD)等方法研究了PLGA50-b-D2-(PLL9)4对溶液pH值响应性.结果表明随溶液pH由酸性转变为碱性,PLGA50-b-D2-(PLL9)4显示出了多重胶束化行为,同时不对称的线型-树状分子拓扑结构影响了聚集体的形貌,在酸性pH值下形成以PLGA为核的球形胶束,而在碱性pH值下形成以PLL为核的棒状胶束,并分别伴随着PLGA及PLL链段构象从无规线团向螺旋构象的转变.A linear-dendron-like polyampholyte was synthesized via the combination of ring-opening polymerization （ROP）, divergent synthesis procedure and click chemistry. First, azide-terminated poly （y- benzyl-L-glutamate） （PBLG-N3） and the second generation PAMAM （D2） with alkyne focal group and four terminal primary amine groups were synthesized by the ROP of y-benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and divergent synthesis procedure, respectively. Subsequently, PBLG-N3was click conjugated with alkyne focal group of D2 to generate primary amine-terminated linear-dendron-like PBLG-b-D2,which was then used as the microinitiator for the ROP of 8-benzyloxycarbonyl-L-lysine N-carboxyanhydride （ZLL-NCA） to produce the linear-dendron-like copolymer PBLG-b-D2-（ PZLL ）4- The targeted linear-dendron-like polyampholyte, PLGAs0-b-D2- （ PLL9 ） 4, where PLGA is poly （ L-glutamic acid） and PLL is poly （ L-lysine）, was obtained by the hydrolysis of protecting benzyl and benzyloxycarbonyl groups of PBLG and PZLL,respectively. The molecular structures of the intermediates and the final polyampholyte were characterized by 1H-NMR, Fourier transform-infrared spectroscopy （FTIR） and properties and pH-responsive behavior in aqueous gel permeation chromatograph （GPC）. The physical solution were investigated via potentiometric and conductometric titration, 1H-NMR, zeta potential measurement, laser light scattering （ LLS）, scanning electron microscopy （SEM） and circular dichroism spectroscopy （CD）. The results show that PLGA50-b-D2-（ PLL9 ）4 can self-assemble into schizophrenic micelles which can be reversibly produced as a function of pH in pure water,i, e. , it can self-assemble into spherical micelles with PLGA-core at acidic pH and rod-like micelles with PLL-core at alkaline pH, accompanied with the coil-to-helix conformational transition of PLGA and PLL. The linear-dendron-like asymmetrical topological structure is believed to play an impotent role in the morphology fo

关 键 词：聚两性电解质 聚氨基酸 树状 PH响应性 多重胶束化 

分 类 号：O631.3[理学—高分子化学]