构建了快速测定血清中甲胎蛋白(AFP)含量的电流型免疫传感器,该免疫传感器是用壳聚糖固定电子媒介体亚甲基蓝和辣根过氧化物酶(HRP)标记的甲胎蛋白抗体于一次性丝网印刷碳电极(SPCE)表面制备而成.当该免疫传感器在含AFP样品的溶液中于30 ℃培育40 min后,抗原抗体的免疫结合会导致HRP标记对过氧化氢电催化氧化的效率降低.在优化的测定条件下,催化效率的降低与AFP浓度在5.0~110.0 μg·L-1范围内呈线性关系,免疫分析的检出限为1.4 μg·L-1(3σ).对免疫传感器的精密度作了试验，同一支传感器测试结果的相对标准偏差为6.6%;当取3支用同一方法制备的传感器进行测试时，相对标准偏差为9.3%.放置7d后，传感器对AFP的响应值相当于初试值的88%，在pH 7.0的缓冲溶液中的还原电流为原值的96%.

An amperometric alphafetoprotein (AFP) immunosensor was prepared by immobilizing the electron mediator,methylene blue,and the horseradish peroxidase (HRP) labelled AFP-antibody on the surface of screen-printed carbon electrode (SPCE) with chitosan.It was used for the rapid determination of AFP in serum.Upon incubation of the immunosensor in a solution containing AFP sample at 30 ℃ for 40 min,immunocombination between AFP and HRP labelled AFP-antibody was observed,which led to partial hindrance of electron transmission between the active center of HRP and the mediator methylene blue,making a decrease in efficiency of electrocatalytic oxidation of H2O2 by the label HRP.Under optimum conditions of determination,linear relationship was held between the magnitude of decrease in catalytic efficiency and the concentration of AFP in the range of 5.0-110.0 μg·L-1.Detection limit (3σ) was found to be 1.4 μg·L-1.Precision was tested and RSD of 6.6% with the same immunosensor was obtained.Test for precision was also made among 3 immunosensors prepared by the same method,the value of RSD obtained was 9.3%.Test for stability was made by standing for 7 days,its response to AFP was found to be 88% of its initial response,and its reduction current in a buffer solution of pH 7.0 was 96% of its original value.