四环素核酸适配体电化学生物传感器的研制

Development of an Aptasensor for Electrochemical Detection of Tetracycline

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。

The residual antibiotics in agricultural products became one of the most noticeable problems for animal derived food security, which caused many known and potential harm to public health. One of the most common antibiotics used in fodder animals is tetracyclines. Developing the rapid, simple and sensitive biosensor system for tetracyclines detection is very important in food safety control. In this paper, a tetracycline binding aptamer, whose recognition is confirmed by Isothermal Titration Calorimetry, is used as bio-recognizer. The developed biosensor in tetracycline detection and the electrochemical behavior are investigated. Results： By using isothermal titration calorimetry, the aptamer shows a high affinity to tetracycline, the dissociation equilibrium constant is at Kd =51.8p^mol/L. According to the differential pulse voltammetry （DPV） analysis, there is a linear relationship between the log concentration of tetracycline and the charge transfer resistance （AIp） in the tetracycline conc. ranges from 5.0 to 5.0 x 103~xg/L with correlation coefficient of 0.987 6. The detection limit is at 1.0p4/L within a detection time of 15 rain. The detection limit lies obviously lower than the National limited residue of tetracycline （6.0 x 102~g/L） and also lower than other reported aptasensor for tetracycline.