动物源性食品中青霉素残留的电化学核酸适配体传感检测机制研究

Penicillins, which is the typical antibiotic residues in foods of animal origin, has been extensively used in animal husbandry and poultry production to prevent and treat bacterial infections. At present, antibiotic residues has become one of the primary inhibiting factor in animal-derived food safety. It is important to develop the trace analysis technology for the detection of penicillins residues in animal-source food. Aptamer, which can be easily produced via chemical synthesis and has the superior thermal and chemical stability, the high affinity and specificity for their targets, has been considered as an alternative recognition elements for the development of biosensors and bioassays. In this research, the amoxicillin (AMO) and ampicillin(AMP) specific aptamers will be selected by a modified SELEX method, which is an extended form of Toggled-SELEX combined with Flu-Mag SELEX by employing target and counter target molecules sequentially different to generate specific AMP and AMO aptamers. The interactions between targets and aptamers will be examined by spectrometry and PCR. Based on the aptamer - target affinity, a novel stable, high specific and reusable electrochemical aptasensor for the trace analysis of penicillins residues in animal-derived food would be developed with the nanotechnology and signal amplification.

青霉素类抗生素广泛应用于畜禽疾病的预防和治疗，是动物源性食品中常见的抗生素残留物。目前，抗生素残留已成为制约我国动物源性食品安全的首要因素之一，研究青霉素类抗生素残留的痕量检测技术具有重要的理论和现实意义。核酸适配体具有高亲和力、特异性，易合成、易保藏等特点，有望取代抗体或弥补抗体不足成为新一代生物识别分子应用于生物传感检测领域。本课题拟选取阿莫西林和氨苄西林为研究对象，采用切换-荧光磁珠SELEX技术筛选核酸适配体，分析结构特征，并利用光谱法和PCR法研究其与抗生素之间的相互作用机理，测定解离常数。在此基础上，结合纳米技术和信号放大技术，构建高特异性的、稳定的、可反复测定的、多通路、痕量青霉素类抗生素核酸适配体传感检测方法，为抗生素残留的痕量检测和适配体传感测定研究提供一个新思路。

青霉素类抗生素广泛应用于畜禽疾病的预防和治疗，是动物源性食品中常见的抗生素残留物。目前，抗生素残留已成为制约我国动物源性食品安全的首要因素之一，研究青霉素类抗生素残留的痕量检测技术具有重要的理论和现实意义。核酸适配体具有高亲和力、特异性，易合成、易保藏等特点，有望取代抗体或弥补抗体不足成为新一代生物识别分子应用于生物传感检测领域。本研究的目的是获得青霉素类抗生素的一种新型检测配体——核酸适配体，并应用于开发基于核酸适配体的电化学传感检测方法。采用磁珠SELEX技术筛选得到了最优序列，它具有高特异性和亲和性，其解离常数Kd值低于其他序列。以最优的核酸适配体序列作为识别元件构建了以磁珠为载体的电化学适配体传感检测方法，在最优条件下，该方法的检测限为1.0×10-12 mol/L，线性范围从1.0×10-12到1.0×10-8 mol/L（R2=0.9954）。研究还在此基础上建立一种基于碳纳米管掺杂的电化学适配体传感检测方法，其检测限可达1.0×10-13 mol/L。所建立的方法均能成功用于牛奶实际样品的检测，实现了复杂食品基质中青霉素残留的高灵敏、高特异性的定量分析检测。