PDF(Pubmed)
Abstract：
Poly(glycerol monomethacrylate)-block-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA) with worm-like morphology is a typical example of reversible addition-fragmentation chain transfer (RAFT) dispersion polymerized thermo-responsive copolymer via polymerization-induced self-assembly (PISA) in aqueous solution. Chain transfer agents (CTAs) are the key component in controlling RAFT, the structures of which determine the end functional groups of the polymer chain. It is therefore of interest to monofunctionalize the polymers via CTA moiety, for bioactive functionality conjugation and in the meantime maintain the precisely controlled morphology of the copolymers and the related property. In this work, a newly designed CTA 5-(2-(tert-butoxycarbonylamino) ethylamino)-2-cyano-5-oxopentan-2-yl benzodithioate (t-Boc CPDB) was synthesized and used for the RAFT polymerization of PGMA45-PHPMA120. Subsequently, PGMA45-PHPMA120 copolymers with primary amine, maleimide, and reduced L-glutathione (a tripeptide) monofunctionalized terminals were synthesized via deprotection and conjugation reactions. These monofunctionalized copolymers maintain worm-like morphology and thermo-responsive property in aqueous solution (10% w/v), as confirmed by the transmission electron microscopy (TEM) images, and the observation of the phase transition behavior in between 4 °C and room temperature (~20 °C), respectively. Summarily, a range of thermo-responsive monofunctionalized PGMA45-PHPMA120 diblock copolymer worms were successfully synthesized, which are expected to offer potential biomedical applications, such as in polymer therapeutics, drug delivery, and diagnostics.
摘要：
具有蠕虫状形态的聚（单甲基丙烯酸甘油酯）-嵌段聚（甲基丙烯酸2-羟丙酯）（PGMA-PHPMA）是通过聚合诱导的自组装（PISA）在水溶液中的可逆加成-断裂链转移（RAFT）分散聚合的热响应性共聚物的典型例子。链转移剂(CTAs)是控制RAFT的关键组分,其结构决定了聚合物链的末端官能团。因此，通过CTA部分单官能化聚合物是有意义的，用于生物活性官能团缀合,并且同时保持共聚物的精确控制的形态和相关性质。在这项工作中,合成了一种新设计的CTA5-（2-（叔丁氧基羰基氨基）乙基氨基）-2-氰基-5-氧代戊烷-2-基苯甲酸酯（t-BocCPDB），并用于PGMA45-PHPMA120的RAFT聚合。随后，PGMA45-PHPMA120与伯胺的共聚物，马来酰亚胺,通过去保护和缀合反应合成还原的L-谷胱甘肽(三肽)单官能化末端。这些单官能化共聚物在水溶液（10％w/v）中保持蠕虫状形态和热响应性，正如透射电子显微镜（TEM）图像所证实的那样，以及在4°C至室温（〜20°C）之间的相变行为的观察，分别。总之,成功合成了一系列热响应性单官能化PGMA45-PHPMA120二嵌段共聚物蠕虫，有望提供潜在的生物医学应用，比如在聚合物疗法中，药物输送,和诊断。
