基于含苯硼酸聚合物的双响应性胶束

Dual-responsive Micelles Based on Boronicacid-modified Polymer

分别合成了苯硼酸修饰的嵌段聚合物聚乙二醇-b-聚(天冬氨酸-co-天冬酰氨基苯硼酸)[PEG-b-P(Aspco-AspPBA)]和含有二硫键及多元二醇的小分子3,3'-二硫代二[1,2(S)-丙二醇](DTBPD).以DTBPD为小分子交联剂,通过二醇单元与苯硼酸之间的共价酯化作用,诱导PEG-b-P(Asp-co-AspPBA)自组装形成以苯硼酸环酯为核、PEG为壳的交联胶束.利用核磁共振氢谱和激光光散射对胶束的结构进行了表征,并分别测定了该胶束在葡萄糖和氧化-还原试剂二硫苏糖醇(DTT)刺激下的响应行为.结果表明,DTBPD可与聚合物链上的苯硼酸形成苯硼酸环酯,通过交联作用诱导聚合物形成胶束.交联度不同时,胶束对于外界刺激(葡萄糖和DTT的响应行为也不同:随着DTT和葡萄糖浓度的增加,交联度高的胶束只发生响应性溶胀,交联度低的胶束则先溶胀,之后溶胀程度较大的部分胶束则发生解体,导致胶束的平均粒径减小.

Phenylboronic acid modified polymer poly （ethylene glycol）-b-poly （aspartic acid-co-aspartamidophenylboronic acid） [ PEG-b-P （Asp-co-AspPBA） ] as well as a cross-linker 3,3 ＇-dithiobis [ 1,2 （ S ） -propanediol] （DTBPD） which contained disulfide bond and dual-diol groups was successfully synthesized. PEG-b- P（Asp-co-AspPBA） could be mildly cross-linked by DTBPD based on the reaction of PBA and the dual-diol groups, leading to the formation of a novel dual-responsive micelle with boronic ester core and PEG shell. The structure, morphology, and the glucose/redox dual-responsive behavior of the micel]es were systematically investigated by nuclear magnetic resonance（NMR） spectrum and dynamic laser light scattering（DLS）. It was demonstrated that the ratio of diol to PBA （ D ： B） had influence on the dual-responsive behavior of the micelles. At higher ratio of D ： B, only responsive swelling of micelles was observed. While for the micelles with lower ratio of D ： B, larger degree of swelling happened and the micelles gradually dissociated under higher concentrations of glucose ordithiothreitol（DTT）. This kind of dual-responsive micelles may find application in drug delivery in the future.