用于检测癌胚抗原CEA的丝网印刷免疫传感器

The Screen-printed Immunosensor Used in Detecting Carcinoembryonic Antigen(CEA)

采用溶胶-凝胶技术将电子媒介体亚甲基蓝和辣根过氧化物酶（HRP）标记的癌胚抗原（CEA）固定在一次性丝网印刷碳电极表面,制备了CEA免疫传感器.该免疫传感器在含CEA样品的溶液中培育后,抗原-抗体免疫结合物的形成会阻碍HRP活性中心与亚甲基蓝之间的电子传递,使HRP对H2O2电催化氧化的效率降低.循环伏安和计时电流法用于研究免疫电极的电化学特性,在优化的条件下催化效率的降低与CEA质量浓度分别在1.0～6.0 μg/L和6.0～138 μg/L范围内成线性关系,检出限为0.4 μg/L,测定的组内和组间相对标准偏差分别为7.4%和11.2%.该测定无须分离、洗涤步骤,分析时间短,操作方便,检测成本低,具有实际应用价值.

A new type of immunosensor for the determination of carcinoembryonic antigen （CEA） was made by sol -gel techniques co-immobilizing methylene blue and horseradish peroxidase （HRP） labeled CEA antibody on the screen-printed electrode surface. After the immunosensor was incubated with CEA solution, the access of activity center of the HRP to methylene blue was partly inhibited, leading to the decrease of the catalytic efficiency of the HRP to the oxidation of H2O2. Cyclic vohammetry and chronoamperomeric current -time curve were employed to investigate the electrochemical characteristics of the immunosensor. Under optimal experimental conditions, there is a linear decrease of the catalytic efficiency in two CEA concentration ranges from 1.0 to 6.0 μg/L and 6.0 to 138 μg/L, respectively. The detection limit is 0. 4 μg/L and with intra-assay RSD of 7.4% and inter-assay RSD 11.2% at 50 μg/L CEA concentrations. Due to the avoiding separation and washing step, the method shortens the analytical time greatly and lowers the detection cost, which is valuable in clinical immunoassay.