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农产品抗生素残留是目前动物性食品安全中的突出问题。四环素的简便、快速检测方法是食品安全控制中十分重要的技术。本研究利用等温滴定量热法筛选到的四环素核酸适配体做识别分子制作生物传感器,用电化学方法研究了该生物传感器检测四环素的电化学行为。结果:等温滴定量热法筛选出一条对四环素有高亲和力的适配体,解离平衡常数Kd=51.8μmol/L。差分脉冲伏安分析,在5.0~5.0×103μg/L浓度范围内,峰电流值的变化△Ip与四环素浓度的对数呈现良好的线性关系,相关系数R2=0.987 6,检测限为1.0μg/L,反应时间为15min。该检测限明显低于目前国家限定的四环素残留量(6.0×102μg/L),也低于目前其他报道的四环素适配体传感器的检测限。
Antibiotic residues of agricultural products are the prominent problems in animal food safety. Tetracycline’s simple, rapid test method is a very important technology in food safety control. In this study, tetracycline aptamer was screened by isothermal titration calorimetry to make a biosensor. The electrochemical behavior of tetracycline biosensor was studied electrochemically. Results: Isothermal titration calorimetry screened an aptamer with high affinity to tetracycline. The dissociation equilibrium constant Kd was 51.8μmol / L. Differential pulse voltammetric analysis, in the range of 5.0 ~ 5.0 × 103μg / L, the change of peak current △ Ip and tetracycline concentration logarithm showed a good linear relationship, the correlation coefficient R2 = 0.987 6, the detection limit of 1.0μg / L, the reaction time is 15min. This limit of detection was significantly lower than the current national limit of tetracycline residues (6.0 × 102 μg / L), which is also lower than the limit of detection of other reported tetracycline aptamer sensors.