基于甲胎蛋白抗体和巯基丁二酰胺铜(Ⅱ)共固定修饰电极的人血清中甲胎蛋白免疫传感器

Electrochemical Immunosensor for α-Fetoprotein Antigen Based in Human Serum on α-Fetoprotein Antibody and Mercapto Succinic Amide Copper Coimmobilized Electrode

研制基于甲胎蛋白抗体(Ab-AFP)和巯基丁二酰胺铜(Ⅱ)(CuL)共固定修饰玻碳电极(GCE|Ab-AFP/TiO2/CuL)的免疫传感器,用于测定人血清中AFP抗原水平。该免疫传感器是利用溶胶-凝胶气相沉积技术,将AFP抗体分子固定在CuL修饰玻碳电极表面制备而成。电极表面的CuL具有电活性,对H2O2有良好的电化学还原催化。当该免疫传感器在含AFP样品的溶液中于25℃温育30min后,AFP抗原与Ab-AFP抗体分子的免疫结合物导致CuL的电子传递被部分阻碍,使CuL对H2O2电催化还原的效率降低,电流值的下降量和AFP浓度成正比,可用于AFP定量测定。在pH=6的PBS中,25℃温育30min的优化条件下,该传感器对AFP的检测线性范围为0.5～3.9和3.9～100ng/mL,检出下限为0.081ng/mL(3σ)。该免疫传感器制备过程比基于酶标抗体修饰传感器简单,尤其是对H2O2催化响应迅速,稳定性好,可以在磷酸盐缓冲溶液中稳定存放15d。对于构建无试剂的免疫传感器和临床免疫分析提供了一种新颖的方法。

A novel immunosensor for rapid separation-free determination of α-fetoprotein antigen （AFP） in human serum is proposed. The immunosensor is prepared by co-immobilizing AFP antibody（Ab-AFP） and mercapto succinic amide copper（Ⅱ）（CuL） on a glassy carbon electrode （GCE） through titania sol-gel film by vapor deposition method（GCEI Ab-AFP/TiO2/CuL）. The electrochemical behavior of the immobilized CuL displays a surface-controlled electrode process. CuL can be used as an electro-reductive catalyzation for H2O2. After the immunosensor is incubated with AFP solution at 25℃ for 30 min, the access of activity center of CuL is partly inhibited, which leads to a linear decrease of the catalytic efficiency of CuL by H2O2 in two AFP concentration ranges from 0.5 to 3.9 ng/mL and 3.9 to 100 ng/mL. Under optimal conditions the detection limit for AFP immunoassay is 0. 081 ng/mL（3σ）. The immunosensor shows a good accuracy and acceptable storage stability, precision and reproducibility. This method decreases the detection cost and shortens the analytical time, thus would be valuable for clinical immunoassay.