Xu Zhifeng, Uddin Khan Mohammad Ahsan, Kamra Tripta, Schnadt Joachim, Ye Lei
Division of Pure and Applied Biochemistry, Lund University , Box 124, 221 00 Lund, Sweden.
ACS Appl Mater Interfaces. 2014 Feb 12;6(3):1406-14. doi: 10.1021/am405531n. Epub 2014 Jan 28.
Boronic acid affinity gels are important for effective separation of biological active cis-diols, and are finding applications both in biotech industry and in biomedical research areas. To increase the efficacy of boronate affinity separation, it is interesting to introduce repeating boronic acid units in flexible polymer chains attached on solid materials. In this work, we synthesize polymer brushes containing boronic acid repeating units on silica gels using surface-initiated atom transfer radical polymerization (ATRP). A fluorescent boronic acid monomer is first prepared from an azide-tagged fluorogenic boronic acid and an alkyne-containing acrylate by Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction (the CuAAC click chemistry). The boronic acid monomer is then grafted to the surface of silica gel modified with an ATRP initiator. The obtained composite material contains boronic acid polymer brushes on surface and shows favorable saccharide binding capability under physiological pH conditions, and displays interesting fluorescence intensity change upon binding fructose and glucose. In addition to saccharide binding, the flexible polymer brushes on silica also enable fast separation of a model glycoprotein based on selective boronate affinity interaction. The synthetic approach and the composite functional material developed in this work should open new opportunities for high efficiency detection, separation, and analysis of not only simple saccharides, but also glycopeptides and large glycoproteins.
硼酸亲和凝胶对于有效分离生物活性顺式二醇非常重要，并且在生物技术产业和生物医学研究领域都有应用。为了提高硼酸盐亲和分离的效率，在附着于固体材料的柔性聚合物链中引入重复硼酸单元是很有意思的。在这项工作中，我们使用表面引发的原子转移自由基聚合（ATRP）在硅胶上合成了含有硼酸重复单元的聚合物刷。首先通过铜（I）催化的1,3 - 偶极环加成反应（CuAAC点击化学）由叠氮标记的荧光硼酸和含炔基的丙烯酸酯制备荧光硼酸单体。然后将硼酸单体接枝到用ATRP引发剂改性的硅胶表面。所得到的复合材料在表面含有硼酸聚合物刷，并且在生理pH条件下显示出良好的糖类结合能力，并且在结合果糖和葡萄糖时显示出有趣的荧光强度变化。除了糖类结合外，硅胶上的柔性聚合物刷还能够基于选择性硼酸盐亲和相互作用快速分离模型糖蛋白。这项工作中开发的合成方法和复合功能材料不仅为简单糖类，也为糖肽和大型糖蛋白的高效检测、分离和分析开辟了新的机会。
