离子液体基电活性纳米多孔复合材料的制备及其在电化学生物传感器中的应用

The maintainance of enzymatic activtiy and the introduction of electron mediator were important factors affecting the performance of the second-generation electrochemical biosensor. In view of this, nanoporous materials, such as mesoporous silica and clay were chosen as the matrixs to construct the novel biosensor. Firstly, the nanoporous materials were modified with ionic liquids groups which endowed the materials with ion-exchange property. Secondly, with help of ion-exchange property and porosity nature of the nanoporous materials, the co-immobilization of water-soluble electron mediator and enzyme in porous matrix could be successfully achieved. Then, the novel biosensor could be constructed by the resulting composites. In comparison with traditional polymer based biosensor, the nanoporous composites were more attractive because of their nanoporous structure and large specific surface area. The porous structure of the composites gave high loading of enzyme and promoted the transfer rate of the substance. In addition, the nanopore of the composites could also provide the biocompatible environment for immobilized enzyme, which was expected to make the sensor with good stability under extreme conditions. Moreover, the electron transfer mechanism of the enzyme immobilized in ordered inorganic structures was also studied, which could provid a theoretical basis for the rational design and construction of novel composites and electrochemical biosensor.

酶的活性保持及电子媒介体的引入方式是影响第二代电化学生物传感器性能的重要因素。鉴于此，本项目拟以介孔硅和粘土层状材料等酶的优良载体为基底，对其进行离子液体修饰化，利用修饰化离子液体的离子交换性实现多种水溶性电子媒介体的固载，制备系列电活性纳米多孔材料。在此基础上，利用物理吸附或"剥离-重组装"方法固载酶，构筑新型电化学生物传感器。由于该方法可实现酶与水溶性电子媒介体在纳米孔道中的共同固载，因而不但可有效解决以往研究中使用聚合物为固载基底所造成的酶固载量低等缺点，还可为固载酶提供适宜的微环境，并有利于电催化过程中物质的传输和扩散。基于此，传感器有望具有良好的性能以及在极端条件下的检测稳定性。此外，以纳米多孔材料所构筑的电化学生物传感器为模型，研究酶在有序结构中的电子传递机理，探讨传感器性能与载体结构之间的关系，可为后续优化材料、合理设计高性能传感器提供理论依据。

电化学生物传感器在医疗，食品，工业等国计民生方面的应用广泛，对传感器性能的提高依赖于对其机理的研究，新材料的应用和构筑方法的改进。本研究开展了以离子液体基介孔材料（MCF-IL）为载体固载电活性小分子铁氰根离子（Fe(CN)63-）制备无酶传感器的研究。其中，重点研究了固载铁氰根离子（MCF-IL-Fe(CN)63-）修饰电极对过氧化氢的催化性能。研究工作中首次指出Fe(CN)63-并非H2O2电化学催化还原的催化剂。首次提出普鲁士蓝（PB）修饰电极在H2O2的催化还原中存在Fe(CN)63-，Fe3+引起的副反应，同时，对该实验的机理及后期PB的应用进行了研究，取得了重大进展。此外，本项目还选用目前研究中最热门的性能最独特的层状材料石墨烯（GP）为基底材料，使用修饰化片状GP材料为载体固载辣根过氧化物酶等氧化还原活性酶，构建了第三代电化学生物传感器。GP的表面惰性限制了其在电化学传感器中的研究，修饰化GP的应用克服了传感器构筑中片层间团聚等问题，GP的引入明显改善了传感器的性能。本项目的部分研究已获得多项成果，已在《Science of Advanced Materials》，《Acta Chim. Sinica 》，《中国科学》，《分析测试学报》等国内外专业期刊上发表相关论文7篇。受理专利1篇。本项目的完成，不仅成功实现了传感器的构筑，而且发现了Fe(CN)63-催化新现象，提出了新的机理，而且为制备高稳定性PB提出了新方法。以此为基础，还可将研究方向过渡到免疫传感器、高性能PB的制备及应用、PB的电芬顿研究等后续工作中。