Department of Materials, ETH-Zürich , CH-8093 Zürich, Switzerland.
J Am Chem Soc. 2014 Apr 23;136(16):5872-5. doi: 10.1021/ja501632r. Epub 2014 Apr 10.
Catalytic action of an enzyme is shown to transform a non-assembling block copolymer, composed of a completely non-natural repeat unit structure, into a self-assembling polymer building block. To achieve this, poly(styrene) is combined with an enzyme-sensitive methacrylate-based polymer segment carrying carefully designed azobenzene side chains. Once exposed to the enzyme azoreductase, in the presence of coenzyme NADPH, the azobenzene linkages undergo a bond scission reaction. This triggers a spontaneous 1,6-self-elimination cascade process and transforms the initially hydrophobic methacrylate polymer segment into a hydrophilic hydroxyethyl methacrylate structure. This change in chemical polarity of one of the polymer blocks confers an amphiphilic character to the diblock copolymer and permits it to self-assemble into a micellar nanostructure in water.
酶的催化作用被证明可以将一种完全由非天然重复单元结构组成的无组装嵌段共聚物转化为自组装聚合物构建块。为了实现这一点，将聚苯乙烯与一种酶敏感的甲基丙烯酸酯基聚合物段结合，该聚合物段带有精心设计的偶氮苯侧链。一旦暴露于酶偶氮还原酶，在辅因子 NADPH 的存在下，偶氮键会发生键断反应。这引发了自发的 1,6-自身消除级联过程，并将最初的疏水性甲基丙烯酸酯聚合物段转化为亲水性羟乙基甲基丙烯酸酯结构。聚合物链之一的化学极性的这种变化赋予二嵌段共聚物两亲性，并允许其在水中自组装成胶束纳米结构。
