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。

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.