基于酶催化沉积放大的电化学阻抗法用于人免疫球蛋白M的检测

Electrochemical Impedance Method Based on Enzyme-Catalyzed Depositing Enlargement Used for the Immunoassay of Human Immunoglobulin M

提出了一种基于酶催化沉积放大的电化学免疫分析方法。先通过免疫夹心反应，将酶标抗体（羊抗人IgM-HRP）固定到电极表面。通过HRP催化双氧水氧化3，3＇-二氨基联苯胺在电极表面形成不溶性沉积物，从而放大电化学检测信号。实验通过蛋白A实现抗体的定向固定。考察了包被抗体的浓度和包被溶液的pH对抗体固定的影响，以及酶标抗体的用量和沉积时间对免疫分析的影响。传感器信号响应与人免疫球蛋白M（IgM）浓度在2．1—670μg／L范围内具有良好的线性关系；检出限达0．08μg／L。

A novel electrochemical immunoassay method based on enzyme-catalyzed depositing enlargement is proposed. Primarily, the horseradish peroxidase （HRP）-labeled antibody （goat-anti-immunoglobulin M （IgM）-HRP） was immobilized on the electrode surface by sandwich method （antibody/antigen/antibody- HRP）. Then the undissolving deposition was formed on the electrode surface by using HRP catalyze hydrogen peroxide to oxidize 3,3＇-diaminobenxidine tetrahydrochloride dihydrate. So the electrochemical signal of the electrode is enlarged greatly. The immobilization of antibody was realized by using protein A. The effects of experimental conditions, such as the concentration of antibody, pH of incubated solution, the amount of enzyme-labeled antibody and the depositing time on the performances of immunassay were discussed respectively. The formed immunosensor can be used to quantitatively determine human IgM in the range of 2.1 - 670 μg/L, and the detection limit is 0.08 μg/L.