Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. W., Montreal, Quebec, Canada H4B 1R6.
Macromol Rapid Commun. 2011 Oct 18;32(20):1652-7. doi: 10.1002/marc.201100372. Epub 2011 Aug 19.
Thiol-responsive symmetric triblock copolymers having single disulfide linkages in the middle blocks (called mono-cleavable block copolymers, ss-ABP(2)) were synthesized by atom transfer radical polymerization in the presence of a disulfide-labeled difunctional Br-initiator. These brush-like triblock copolymers consist of a hydrophobic polyacrylate block having pendent oligo(propylene oxide) and a hydrophilic polymethacrylate block having pendent oligo(ethylene oxide). Gel permeation chromatography and (1)H NMR results confirmed the synthesis of well-defined mono-cleavable block copolymers and revealed that polymerizations were well controlled. Because of amphiphilic nature, these copolymers self-assembled to form colloidally stable micelles above critical micellar concentration of 0.032 mg · mL(-1). In response to reductive reactions, disulfides in thiol-responsive micelles were cleaved. Atomic force microscopy and dynamic light scattering analysis suggested that the cleavage of disulfides caused dissociation of micelles to smaller-sized assembled structures in water. Moreover, in a biomedical perspective, the mono-cleavable block copolymer micelles are not cytotoxic and thus biocompatible.
具有单个二硫键的硫醇响应对称三嵌段共聚物（称为单可裂解嵌段共聚物，ss-ABP(2)）是通过二硫键标记的双官能 Br-引发剂存在下的原子转移自由基聚合合成的。这些刷状三嵌段共聚物由带有侧基的疏水性聚丙烯酸酯嵌段和带有侧基的亲水性聚甲基丙烯酸酯嵌段组成，其中侧基为聚氧化丙烯和聚氧化乙烯。凝胶渗透色谱和（1）H NMR 结果证实了单可裂解嵌段共聚物的合成，并表明聚合反应得到了很好的控制。由于两亲性，这些共聚物在临界胶束浓度（CMC）0.032mg·mL-1以上自组装形成胶体稳定的胶束。响应还原反应，硫醇响应胶束中的二硫键被切断。原子力显微镜和动态光散射分析表明，二硫键的断裂导致胶束在水中解离为更小尺寸的组装结构。此外，从生物医学的角度来看，单可裂解嵌段共聚物胶束没有细胞毒性，因此具有生物相容性。
