电泳沉积法制备重氮功能化石墨烯及其生物传感特性研究

Graphene-based materials have been widely used in electrochemical biosensing applications due to its high surface area, extraordinary conductivity and good biocompatibility. In the process of electrode coating with graphene-based materials, solution-based techniques are usually applied. However, the deposited films always suffer from ill-defined coverage, poor homogeneity and weak adhesion, leading to unsatisfactory sensing performance. In this project, we propose the use of a facile electrophoretic deposition technique for the deposition of reduced graphene oxide (rGO) with aryl diazonium compounds, in which process graphene oxide (GO) gets reduced with spontaneous surface modification of aryl radicals with B-(OH)2, COOH and alkynyl groups through covalent sp2 bonding by the reduction of diazonium salts in the meantime. After modification, the interfaces are of high interest for designing highly sensitive sensing platforms. rGO modified with boronic acid groups could be applied for non-enzymatic glucose sensing under weak alkaline conditions. While carboxyl and alkynyl terminated interfaces could be used for the construction of lysozyme aptasensor after aptamer immobilization through EDC/NHS coupling or “Click” reaction. Highly sensitive detection of lysozyme in serum will be achieved in direct approach without labeling. By varying the deposition parameters, functionalized rGO matrices with adjustable nanostructure and constitution can be achieved in a straightforward way. The sensing performance of established sensing platforms will also be strengthened. The study will find its wide application in experimental and theoretical domain in developing biosensors with high sensitivity, good reliability, strong stability and wide feasibility.

石墨烯材料因其超高的比表面积、优异的导电率和良好的生物兼容性而被广泛应用在电化学生物传感体系中。运用溶液沉积技术制备的石墨烯涂层电极往往由于覆盖性差、均匀度低、附着力弱等问题而使其传感特性受到限制。本项目拟采用简单易行的电泳沉积技术，实现氧化石墨烯和芳基重氮盐离子在电极基片上的同步还原，同时将含有硼羟基、羧基、炔基的芳基基团通过共价连接方式修饰在石墨烯的sp2晶格上，制备出功能化基团修饰的石墨烯电极材料。因而可以构建适用于低碱性电解质条件下的苯硼酸基无酶葡萄糖检测体系，或通过酰胺化反应/“点击”化学法固载筛选后的溶菌酶适体构建无标记超灵敏溶菌酶适体传感器，并应用于临床血清样品中溶菌酶的检测。通过优化电泳沉积条件，本项目可实现功能化石墨烯材料的微观构型及组分调控，全面优化电极体系的电化学传感性能，为开发灵敏度高、准确度好、稳定性强、适用范围广的新型生物传感器奠定重要的临床应用和理论基础。

当前生物、医学、食品、环境等领域对灵敏度高、准确度好、抗干扰能力强、稳定性好的生物传感器有迫切的需求。在常用的电化学生物传感体系中，电极材料的可控制备及生物识别元素的有效负载是影响传感器性能的关键因素。本项目以构建高性能生物传感器为研究目的，采用电泳沉积、两部法沉积等方式制备了一系列生物传感性能优异的材料。石墨烯的重氮功能化同步实现了石墨烯薄膜的均匀化可控制备及生物识别元素的接口化负载，经适体修饰后成功实现溶菌酶的超灵敏检测；针对无酶葡萄糖检测，设计制备了基于二维材料（石墨烯、二硫化钼）及过渡族金属（Ni, Co）的复合物，充分发挥了双组分的协同效应；此外，就无酶过氧化氢检测，开发了基于铜基纳米氧化物/碘氧化铋复合物同型异质结的光电化学传感体系。结果表明，通过组分复合和调控，可全面发挥不同材料体系优势，提高传感性能。本项目构建的传感体系，均可用于真实样品如人体血清、医用消毒剂等中溶菌酶、葡萄糖、过氧化氢的检测。上述研究结果为新型生物传感器的开发提供了数据支持，有助于提升传感材料的技术水平，从而为疾病监测、食品检验等提供新的方法指导。