基于核酸适体特异性识别的多氯联苯光电化学传感器的构筑及应用研究

Polychlorinated biphenyl (PCBs) is a kind of persistent environmental pollutants. It is an important and urgent research subject to explore the novel and simple analytical method for detection of PCBs. Owing to the low concentration of PCBs, numerous congeners and complex matrix effect in the environment, it is hard to achieve fast, highly sensitive and selective detection. In the study, we propose to develop a series of PCBs photoelectrochemical biosensors based on aptamer as the recognition element by introducing aptamer to photoelectrochemical sensing interface, and combining the two advantages of ultrasensitive photoelectrochemical technique and aptamer with specific recognition to PCBs. Meanwhile, the developed sensors would be applied in detection of PCBs in the environment. In the work, TiO2 nanotube arrays-based composite nanomaterial with highly ordered tubular structure, large surface area and good biological compatibility are designed as the ‘micro container’ for anchoring aptamer molecules, which can provide a favorable microenvironment for aptamer molecules to maintain its bioactivity and affinity, and more spaces for increasing the load of aptamer molecules, improving effectively analytical performance of the photoelectochemcial sensors. The constructed photoelectrochemical sensors are expected to obtain not only high sensitivity, but good selectivity for detection of PCB monomer (PCB 126) in the complicated environment. On this basis, the analytical mechanism of sensor and the specific recognition mechanism of aptamer to PCBs would be investigated in the work. In addition, the application of PCBs photoelectrochemical sensors developed by combing photoelectrochemical method with PCBs aptamers would be further expanded to provide much more new methods for detection of PCBs in environment.

多氯联苯（PCBs）是一类持久性环境污染物，探索新颖、简便的PCBs检测方法是一项重要而紧迫的课题。本项目针对PCBs在环境中浓度低、同类物多、干扰复杂，难以实现快速、高灵敏、高选择性检测的难题，提出以具有特异性识别功能的PCBs适配体为识别元件，将其引入至超灵敏的光电化学传感界面；充分结合两者优势构建一系列PCBs光电化学适配体传感器并用于环境检测。通过设计具有直立有序管状结构、表面积大且生物兼容性好的TiO2 纳米管复合材料为组装适配体的“微容器”。该材料不仅为适配体负载提供良好的微环境，保持其生物活性；而且可提供更多的空间增加适配体负载量，有效提升传感器分析性能。以此构建的传感器既可获得高灵敏度，又能实现对复杂环境中PCB单体（PCB 126）的高选择性检测。在此基础上，将深入研究传感器分析原理和特异性识别机制；并拓展PCBs光电化学传感器的应用，为环境中PCBs检测建立更多新方法。

针对多氯联苯在环境中浓度低、同类物多、干扰复杂，难以实现快速、高灵敏、高选择性检测的难题，本项目将高灵敏的光电化学、电化学技术与具有特异性识别性能的适配体结合，构建了系列光电化学、电化学适配体传感平台用于对环境污染多氯联苯检测。项目制备了具有直立有序的管状结构、表面积大且生物兼容性好的N掺杂的TiO2 纳米管、碘氧铋/TiO2纳米管、酞菁锌/TiO2纳米棒、碘氧铋/TiO2纳米棒等复合材料为光活性电极基底。通过SEM、XRD、XPS表征了电极材料的形貌、晶体结构、表面形态及元素化合价；采用紫外漫反射和电化学技术表征了电极材料的光吸收性能和电化学性能。以制备的TiO2纳米复合材料为基底构建了多种光电化学传感器实现了对复杂环境中多氯联苯高灵敏、高选择性检测。在此基础上，进一步很拓展光电化学传感器的应用，实现了对环境污染物双酚A和阿特拉津的高效检测。另外，本项目采用电化学还原法和共沉积法分别制备了不同形貌和电性能的镍铁氰纳米粒子/还原氧化石墨烯纳米复合材料，其中采用共沉积法首次了制备直径为5 nm镍铁纳米粒子负载的还原氧化石墨烯复合材料。以制备的复合材料为电极基底，成功地将镍铁纳米粒子指示探针原位引入电极表面，避免了以往工作需对适配体标记或在测试体系中加入电化学活性基团带来的适配体识别性能下降或出现假阳性的缺点。以镍铁氰纳米粒子/还原氧化石墨烯纳米复合材料构建的电化学适配体传感器成功实现了多氯联苯77和阿特拉津的高灵敏、高选择性检测。本项目构建的多种简单、高效、高灵敏以及高选择性的电化学或光电化学适配体传感平台，为环境有机污染物的监测提供了有力的技术支持。同时，拓宽了适配体与光电化学、电化学技术结合的应用范围，有着广阔的应用前景。