A bioreducible poly(disulfide)-derived amphiphilic block copolymer–drug conjugate (loading content 31%) was synthesized by post-polymerization modification. It shows redox-responsive polymersome assembly in water with aggregation induced emission property arising from the appended Camptothecin (CPT) drug. Glutathione (GSH), a tripeptide overexpressed in cancer cells, triggers a cascade reaction resulting in simultaneous degradation of the polymer backbone (consisting of disulfide linkage) and the release of the pendant drug. The cascade reaction involves GSH trigger cleavage of the backbone disulfide bond producing free thiol followed by its intrachain nucleophilic attack to the adjacent carbonate group that links the appended drug molecule. The polymeric pro-drug exhibits killing efficiency to a cancer cell with remarkably low IC50 value of 3.1 μg/mL (based on the CPT concentration) while it shows negligible toxicity to a normal cell up to polymer concentration 300 μg/mL.
通过后聚合修饰合成了一种双
硫键衍生出的
生物可还原性两亲性嵌段共聚物–药物偶联物(载药量31%)。该偶联物在
水中表现出氧化还原响应性的聚合物囊泡组装,并由于附着的
喜树碱(C
PT)药物而产生聚集诱导发射特性。在癌细胞中过量表达的三肽
谷胱甘肽(GSH)触发了一系列反应,导致同时降解含有双
硫键的聚合物骨架并释放挂接药物。这一系列反应涉及GSH触发器对骨架双
硫键的切割,产生自由
硫醇,随后
硫醇对连接挂接药物分子的相邻
碳酸盐基团的链内亲核攻击。这种聚合物前药对癌细胞表现出高效的杀伤效率,其IC50值极低,为3.1 μg/mL(基于C
PT浓度),而对正常细胞的毒性可忽略不计,聚合物浓度高达300 μg/mL时仍无毒性。