自支撑碳载功能化TiO2复合材料的制备及电化学传感研究

Electrochemical biosensors shows a promising app1ication in clinical diagnosis, food and medical analysis, environmental protection and biotechniques. Biosensors based on enzymes attract more and more attention because of its good se1ectivity and high sensitivity . But most redox centers of proteins deep1y bury in the proteins, making the direct electron transfer between proteins with the electrodes become very difficult, and these proteins are easy to deactivation. In this project, a three-dimensional (3D), flexible, conductive and biocompatible nitrogen-, transition metal-doped and nanoparticles-loaded titanium dioxide on the free-standing graphitized nanofibers (GNF) membrane (N-, T-, M@N-TiO2/GNF) is prepared via electrospinning, carbonization, sol-gel, biomimetic and low-temperature calcination techniques. The as-prepared composite is incorporated to an electrode without any treatments, and applying for the effective immobilization of biomolecules (e.g., glucose oxidase, cholesterol oxidase and cytochrome C and so on), excepting to improve its e1ectron transfer abi1ity, and overcome its disadvantges of deactivation and enhance its 1ife-time of biosensors. The effect of chemical composition, particle size, microstructure, surface characteristics and morphology of modifying materials on the electrochemica1 performance of biosensor are researched. We further systematic study the impact of N-doping and unique structural characteristics on the direct electrochemistry and electroactivity of enzymes and proteins. It is expected that the fabricated glucose, cholesterol and insulin biosensors could be used as flexible sensing with high-performance, and further improve its sensitivity, stability and selectivity.

电化学生物传感器在临床诊断、食品分析、环保和生物技术等领域有着广泛的应用。酶型生物传感器因选择性好、灵敏度高备受关注。但大部分酶的活性位深埋在肽链内部，使酶与电极间的电子传递很难实现且易失活。本课题拟结合电纺、绿色仿生及低温煅烧技术，以自支撑电纺石墨化碳纳米纤维膜（GNF）为基底，经济、快速、高效制备三维、柔性、导电及生物相容性的氮掺杂、纳米粒子负载TiO2复合材料（TiO2/GNF），做成一体电极用于生物大分子（如葡萄糖氧化酶、胆固醇氧化酶及细胞色素C等）的有效固载，改善电子传递能力，克服其易失活及寿命短的缺陷；研究TiO2/GNF独特结构对酶的直接电化学和电催化行为的影响；探讨TiO2，金属纳米粒子与GNF的界面作用及界面电荷转移机制；考察复合材料的形貌、结构、组成与葡萄糖、胆固醇及胰岛素等生物传感器性能之间的关系。构建的传感器有望用于柔性传感器并进一步提高其灵敏度、选择性和稳定性。

电化学生物传感器在临床诊断、食品分析、环保和生物技术等领域有着广泛的应用。酶型生物传感器因选择性好、灵敏度高备受关注。但大部分酶的活性位深埋在肽链内部，使酶与电极间的电子传递很难实现且易失活，如何保持酶的活性并实现酶与电极间的快速电子传递是相关研究面临的挑战。TiO2中的Ti原子与酶的氨基和羧基形成的配位键可以保持酶的生物电催化活性，并促进酶与电极表面的电子转移，是一种有效的固定蛋白质分子的新型材料。但是TiO2通常呈粉体状，纳米颗粒容易堆叠、团聚，影响电化学活性，并且TiO2是一种半导体，其导电性较差。. 本项目在国家自然科学基金地区基金（21864014）资助下，按照项目原定计划在新型自支撑碳载功能化TiO2复合材料的设计、制备及电化学传感应用等方面，开展了一系列研究工作，顺利完成了项目预期目标。主要工作包括：结合静电纺丝、绿色仿生及低温煅烧技术，以自支撑电纺石墨化碳纳米纤维膜（GNF）为基底，可控、批量制备了氮掺杂、过渡金属掺杂及（双）金属纳米粒子负载的TiO2功能化复合材料。此复合材料直接做成一体电极，用于生物大分子（如葡萄糖氧化酶、乙酰胆碱酯酶等）的负载，提高了生物酶、蛋白在电极表面的电催化活性、催化稳定性并简化了电极的制备过程；系统研究了复合材料的生长机理、掺杂作用；探索了复合材料的形貌、组成、微结构对葡萄糖氧化酶、乙酰胆碱酯酶等的直接电化学和电催化行为的影响；成功应用于葡萄糖、胆固醇、胰岛素及有机磷农药等目标物的精准、灵敏检测，研究内容具有重要的科学意义和应用前景。