电化学核酸适配体传感器研制及其在多氯联苯快速检测中的应用

Polychlorinated biphenyls (PCBs) as one of the important persistent organic pollutants (POPs) are toxic chemicals that usually exist at trace level, but inflict adverse impact on human health and environmental security. It is one of the most fundamental concerns in the global society nowadays, and has attracted attention from governments and the public. Thus, there is a crucial need to develop new techniques which can rapidly screen and detect these toxic compounds in a selective and sensitive manner in order to safeguard environment security and human health. In this work, an electrochemical aptamer biosensor is proposed for the rapid screening and detection of PCBs in water. PCBs generally contain multiple isomers at different degrees of chlorination and exhibit a wide range of toxic effects, and these effects may vary depending on the specific PCB. Therefore, a single isomer of PCBs is usually chosen as a representative target. The development of corresponding detection method for individual PCB with high selectivity and sensitivity, low detection limit and good portability is more significant than the detection of all PCBs. Based on the mechanism of strong interaction between the toxic 3,3',4,4'-tetrachlorobiphenyl (PCB77) and aptamer, an electrochemical aptamer biosensor is constructed for the rapid, portable, reliable, highly selective and sensitive detection of PCB77. The thiolated aptamer is immobilized on the gold nanoparticle-nano graphene composite, and a novel electrochemical aptamer biosensor is obtained. As a practical alternative or supplement to traditional chromatographic techniques (Gas Chromatograph-Mass Spectrum), aptamer-based electrochemical biosensor possesses many advantages, such as cost-effective, fast and portable detection, and so on. It makes in situ and real time monitoring possible without extensive and time-consuming sample preparation. The proposed biosensor will be a promising "alarm" tool for rapid screening of PCBs pollutants in real water samples.

持久性有机污染物多氯联苯（PCBs）导致的污染问题已经引起各国政府和民众的高度关注，发展用于环境中PCBs快速筛查和预警手段对于保障环境安全和公众健康至关重要。本项目拟研究一种新型的电化学核酸适配体传感器应用于水中PCBs快速现场检测。然而PCBs同系物种类繁多，其同族体物理化学及毒物学性质差异很大，因此选择单个PCBs作为代表，进行高选择性定性定量研究具有更大的应用价值。基于具有三致"毒性"的3,3',4,4'-四氯联苯（PCB77）与核酸适配体有较强相互作用的机理，将末端修饰巯基的核酸适配体固载到高电导性的金纳米粒子石墨烯复合材料表面，构建能够满足水中PCB77快速检测要求的高选择性、高灵敏度、低检测限、可靠便携的核酸适配体传感器。作为常规分析方法的有力补充，该方法具有气质联用常规方法所不具备的一些优势（如快速、便携等），在环境中PCBs的快速现场风险评价和削控方面具有潜在的应用前景。

多氯联苯（polychlorinated biphenyls, PCBs）是一种典型的、环境中广泛存在的持久性有机污染物（persistent organic pollutants，POPs），日本、中国台湾等地区都曾发生过因食用多氯联苯污染的米糠油而导致上千人中毒、近百人死亡的恶性事件，因此，多氯联苯污染物的快速、现场、定量检测在食品安全、临床和环境监测等方面显得十分重要。多氯联苯存在209种同系物，多氯联苯同系物的分离分析一直是分析的难点，从而限制了多氯联苯的分析检测，影响了测定结果。3,3’4,4’-PCB(PCB77)是一种具有强烈毒性效果的无邻位取代的共平面类二恶英（PCBs），环境中含量较高的类二恶英PCBs，其反应活性较高，“三致”毒性大，虽然以痕量形式存在，但可通过食物链浓缩放大危害人体健康，对生态环境和人类健康影响非常显著。本项目以天然鳞片石墨和人造石墨为原料，采用球磨法制备了单层石墨烯，采用液相自组装方法将金纳米粒子负载到高电导率、大比表面积的石墨烯材料表面，发展集金纳米粒子和石墨烯的优点为一体、生物相容性和电化学换能能力都很好的生物传感材料，构建能够满足水体中PCBs污染物快速检测要求的高灵敏度、高选择性、低检测限、可靠便携的核酸适配体生物传感器，建立生物传感器对PCBs的定量检测方法。该方法检测线性范围是1 pg L-1到10 µg L-1范围内，检测下限是0.3 pg L-1。本方法只对PCB77有响应信号，其他PCB同系物和具有基因毒性的六氯苯都没有响应，是一种选择性检测PCB77的可靠技术。本方法还具有气相色谱-质谱联用方法所不具备的一些优势（快速、便携、廉价、不需要复杂的样品预处理和专业的操作人员），作为常规分析方法的有力补充，在环境中PCBs的现场快速风险评价和削控方面具有潜在的应用前景。同时，基于研究方法，研制了实验室样机并应用于真实水样的检测，检测结果可靠性好，具有重要的科学意义和创新性。