食品中污染物氨基脲的可视化核酸适配体传感器的检测机制研究

Semicarbazide (SEM) is a key metabolite of veterinary medicine nitrofurans and food additives azobisformamide, which would cause mutagenicity and carcinogenicity to human and always be detected in animal products, seafood, flour products and food with glass package. SEM poses a threat to public health in polluted-food consumption, due to their wide range of pollution, high rate of outbreak, and severe outcomes. In this project, we developed a universal biosensor system for simple, visual and rapid detection of SEM in food. In this system, specific aptamers against SEM were used as a recognition element, and DNA self-assembly was used for signal amplification. The formed G-quadruplex with peroxidase activity oxidized the colorless substrate to blue production for visual detection. The aptamer-based colorimetric system was sensitive, specific, easy to use, and does not require the use of complex and expensive instrumentation. Most importantly, the results can be observed by the naked eyes. The shining points of this project are 1) the aptamer for SEM is firstly screened and used as recognition element in the detection; 2) the universal biosensor system using DNA self-assembly for signal amplification and the colorimetric system are visual and cheap, without expensive instruments, which poses the potential application in field-test of SEM in different food products.. These advantages posed it suitable in field-testing of SEM pollution in food. This project could provide a new route in improving the quality of food and it is significant in the pollution control of SEM pollution. Moreover, the colorimetric analysis system can also be used for the development of rapid detection kit, which has great potential in the area of food safety control.

氨基脲具有致诱变性和致癌性，主要来源于硝基呋喃类兽药及食品添加剂偶氮二甲酰胺的分解，常在畜产品、海产品、面制品及玻璃包装食品中检出。鉴于食品中氨基脲污染范围广、危害大、且检测过程对检测仪器和操作要求高的特点，本项目拟建立一种操作简单、特异、灵敏的核酸传感器对氨基脲进行可视化检测，以满足氨基脲现场快速筛查需要。本项目拟筛选氨基脲的特异核酸适配体aptamer，然后构建DNA发卡自组装信号扩增系统对aptamer信号进行放大，最后通过G-四聚体的拟酶活性催化底物显色反应。本项目的创新之处在于：（1）首次筛选并利用氨基脲核酸适配体作为检测识别元件；（2）设计的DNA自组装扩增体系和可视化分析方法摆脱了对仪器读取结果的依赖，肉眼观察，便于现场实时分析。该项目为食品中氨基脲的现场分析提供了一种新的思路和手段，对提高食品质量，控制致癌物的污染具有重要的意义，在食品安全检测中具有广泛的应用前景。

氨基脲具有致诱变性和致癌性，主要来源于硝基呋喃类兽药及食品添加剂偶氮二甲酰胺的分解，常在畜产品、水产品、面制品及玻璃包装食品中检出。鉴于食品中氨基脲污染范围广、危害大、且检测过程对检测仪器和操作要求高的特点，本项目建立了一种操作简单、特异、灵敏的核酸试纸条传感器对氨基脲进行可视化检测，以满足氨基脲现场快速筛查需要。本项目以核酸偶联抗体作为氨基脲的特异识别元件，然后构建双酶等温链置换核酸扩增方法对核酸信号进行放大，最后通过试纸条对靶标氨基脲小分子进行快速检测。整个检测过程可常温操作，1h内读取结果，检测灵敏度为20ppb,并且检测成本较低、结果肉眼可见，适用于现场快速分析食品中氨基脲的污染情况。. 本项目以食品安全污染因子快速检测为目的，利用核酸适配体的特异性识别和核酸自组装等温扩增的特征，设计和构建了多种核酸适配体传感器。主要成功包括1）构建一种可视化检测体系用于呋喃类农药残留的四重检测方法；2）构建了基于核酸适配体识别和核酸试纸条相结合的可视化平台；3）构建了核酸扩增荧光检测方法，并在重金属离子检测中得以应用；4）构建了基于核酸适配体识别和石墨烯材料的荧光检测平台，为后期SEM适配体传感器构建提供良好的基础；5）围绕核酸适配体在食品安全检测中的应用，综述了多种核酸适配体传感器的设计思路及应用前景。. 通过该项目实施，发表了SCI收录论文10篇（其中一区3篇，二区5篇）和中文卓越期刊论文1篇；以项目研究为基础，获批主持2项科研项目（山东省高等学校青创人才引育创新团队项目1项和青岛市科技惠民专项1项）；授权发明专利2项；培养了研究生3名。. 该项目所建立的检测方法具有通用性，能检测不同物质，对提高食品质量，控制食品危害因子的污染具有重要意义，能很好服务于“健康中国2030”和保障人民“从农田到餐桌”舌尖上的安全。.