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提出了一种基于纳米金/硫堇修饰金电极的ABA安培免疫传感器。该传感器基于H2O2-HRP-硫堇催化波体系构建,其中硫堇为传感介质。当HRP存在时,通过加入H2O2,硫堇的还原电流大幅增加,并且电流的增加依赖于HRP活性。HRP活性又由ABA与HRP酶标抗体结合物调控,产生一个减小的催化波。用BSA封闭硫堇单分子层修饰后可能存在的活性位点以避免非特异性吸附。优化了测定条件,包括酶标抗体和硫堇的最佳比例、培育时间、缓冲液的pH值和H2O2浓度。此传感器的还原电流在ABA浓度0.5~1000ng/mL范围内呈线性下降,回归方程为y=0.0209x+17.071,相关系数为0.9922,检测限为0.2ng/mL。
A novel ABA amperometric immune sensor based on gold nanoparticle / thionine modified gold electrode was proposed. The sensor is based on H2O2-HRP-thionine catalytic wave system, in which thionine is a sensing medium. When HRP is present, the reduction current of thionine greatly increases by the addition of H2O2, and the increase of current depends on the HRP activity. HRP activity in turn by the ABA and HRP enzyme conjugate regulation, resulting in a reduced catalytic wave. BSA was used to block the active sites that may exist after thionine monolayers modification to avoid nonspecific adsorption. The assay conditions were optimized, including the optimal ratio of enzyme-labeled antibody to thionin, incubation time, pH of the buffer and H2O2 concentration. The reduction current of this sensor decreased linearly in the range of 0.5-1000 ng / mL ABA. The regression equation was y = 0.0209x + 17.071, the correlation coefficient was 0.9922, and the detection limit was 0.2 ng / mL.