碳基共价有机骨架复合材料的构筑及高性能电化学传感研究

This project is aiming at synthesizing novel 3D nanocomposites (CCOFs) of porous carbon or graphene with covalent organic frameworks (COFs) to load protein molecules, developing novel electrochemical biosensors with high sensitivity and selectivity. The resulted nanocomposite could both retain the huge surface area and a large number of active sites of the original COFs and significant electricity of carbon materials，could overcome the shortcomings of traditional sensor such as the serious accumulation of active material, low catalytic activity, large mass transfer resistance, and expected to greatly increase the effective specific surface area of electrodes, promote rapid electron transfer between protein molecules and electrode, improve the performance of the sensor. This study includes the following contents: investigating the growth mechanism of COFs on porous carbon or graphene nanosheets by using electrochemical technique together with spectroscopy and microscopy to prepare novel CCOFs; preparing novel electrochemical sensors with fast response and high sensitivity to some sepcific moelcules; systematically studying the relationship between the composition or structure of COFs and performance of such sensors; exploring the mechanism. COFs represent a class of crystalline and highly porous hybrid materials obtained by the assembly of metallic ions and organic ligands with highly tunable structure. Sensors constructed with COFs could mimic enzyme molecule, greatly increase the electrode surface area, promote the effective direct electron tranfer and improve the molecular recognition function, thus improve the sensitivity and selectivity of the sensor. Up to now there are few references about the application of COFs in biosensor, and we will innovatively prepare a novel electrochemical biosensors based on CCOFs. The resulted nanocomposite could not only retain the huge surface area and a large number of active sites of the original COFs and significant electricity of carbon materials, but also produce novel synergistic effect. It will shed some new light on electrochemical sensors.

本项目旨在设计三维碳基共价有机骨架复合材料（CCOFs）作为新型界面固载酶/蛋白质，利用碳材料导电性好和COFs比表面积高、活性点多的优势，克服传统传感器活性材料堆积严重、催化活性低等不足，可望大大增加电极的有效比表面积、促进酶和电极间的电子传递，提升传感器性能。拟以电化学技术为主线，结合谱学和显微镜技术研究系列COFs在石墨烯和多孔碳表面诱导生长规律，研究CCOFs组成、结构等因素与材料比表面积、电催化性能、传质性能间的关系，阐明其规律和机理；进而利用浸泡和电沉积等方式制备CCOFs与酶/蛋白质的复合物，发展能对目标分子快速灵敏检测的传感器。COFs结构高度有序并可自由剪裁，兼具纳米多孔、有机-无机杂化材料的优点，但COFs在电催化传感方面的报道较少。本项目创新地采用碳材料为模板负载COFs构筑传感器，兼具碳材料的导电性和COFs的高比表面及两者协同效应，为发展新型传感器件提供了新思路。

本项目旨在制备一系列COFs及其衍生的纳米复合材料，并将其应用于电化学传感研究，发展高灵敏度、高选择性的新型电化学传感器。项目的研究始终按计划进行，经过项目组全体成员四年来不懈努力地工作，开展了一系列工作并取得了不错的结果。例如我们利用COFs创造了微囊泡环境用于生物酶的装载；利用COFs负载生物酶构建了生物传感器；利用COFs衍生的碳基金属纳米复合材料构建了电化学传感器；利用具有电活性的COFs作为内参信号构建比率电化学传感器；利用具有催化性能的COFs直接构建电化学传感器；利用具有良好吸附性能的COFs实现检测物在电极表面的富集，成功地发展了一系列高灵敏电化学传感器平台。我们的工作以电化学方法为主线，结合光谱、AFM、SEM 和TEM 等一系列表征技术对所合成的纳米材料进行了形貌与结构表征，并系统地探讨了这些基于COFs及其衍生的纳米复合材料的组成、结构等因素与传感器的电催化性能、传质性能间的关系，阐明了其检测规律和机理。结果表明利用COFs创造的微囊泡可以在最大程度上保护酶的生物活性，使其发挥出较好的催化性能；利用COFs作为模板制备得到的负载单分散、小尺寸的金属纳米颗粒的碳基复合材料具有较好的催化效果；电活性COFs作为内参信号大大提高了传感器的稳定性及重现性；COFs对检测物的富集极大地提高了传感器的灵敏度。.本项目创新地采用碳材料为模板负载COFs构筑传感器，兼具碳材料的导电性和COFs的高比表面及两者之间的协同效应，克服了传统传感器活性材料堆积严重、催化活性低等不足，大大增加了电极的有效比表面积、促进了溶液和电极间的电子传递，为传感器的研制向着选择性高、分析速度快、便携简单和性能稳定等方面提供了新思路。相关工作已正式发表SCI论文30篇、发表相关会议论文12篇、申请4项国家发明专利、授权1项国家发明专利、进行邀请及口头报告9次、获江西省自然科学二等奖1次、实现成果转化1项、培养了2名青年科技骨干、10名硕士研究生和4名博士研究生、参加国际国内学术会议共12次（其中参加国际会议2次）。项目执行期间已顺利完成了计划书中预定的各项指标。