Department of Industrial Engineering, University of Salerno, 84084 Fisciano SA, Italy.
Institute for Microelectronics and Microsystems of the National Council of Research (CNR), 80131 Napoli, Italy.
Biosensors (Basel). 2016 Jun 30;6(3):33. doi: 10.3390/bios6030033.
An impedimetric label-free immunosensor on disposable screen-printed carbon electrodes (SPCE) for quantitative determination of Ochratoxin A (OTA) has been developed. After modification of the SPCE surface with gold nanoparticles (AuNPs), the anti-OTA was immobilized on the working electrode through a cysteamine layer. After each coating step, the modified surfaces were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The capacitance was chosen as the best parameter that describes the reproducible change in electrical properties of the electrode surface at different OTA concentrations and it was used to investigate the analytical parameters of the developed immunosensor. Under optimized conditions, the immunosensor showed a linear relationship between 0.3 and 20 ng/mL with a low detection limit of 0.25 ng/mL, making it suitable to control OTA content in many common food products. Lastly, the immunosensor was used to measure OTA in red wine samples and the results were compared with those registered with a competitive ELISA kit. The immunosensor was sensitive to OTA lower than 2 μg/kg, which represents the lower acceptable limit of OTA established by European legislation for common food products.
已开发出一种在一次性丝网印刷碳电极（SPCE）上的基于阻抗的无标记免疫传感器，用于定量测定赭曲霉毒素 A（OTA）。在 SPCE 表面用金纳米粒子（AuNPs）修饰后，通过半胱氨酸层将抗 OTA 固定在工作电极上。在每个涂层步骤之后，通过循环伏安法（CV）和电化学阻抗谱（EIS）对修饰后的表面进行了表征。电容被选为描述电极表面在不同 OTA 浓度下的可重现电性质变化的最佳参数，并用于研究开发的免疫传感器的分析参数。在优化条件下，该免疫传感器在 0.3 至 20ng/mL 之间呈现线性关系，检测限低至 0.25ng/mL，使其适用于控制许多常见食品中的 OTA 含量。最后，该免疫传感器用于测量红酒样品中的 OTA，并将结果与竞争 ELISA 试剂盒的结果进行了比较。该免疫传感器对低于 2μg/kg 的 OTA 敏感，这代表了欧洲法规为常见食品产品规定的 OTA 可接受下限。
