基于碳纳米管修饰的无酶型新型甲胎蛋白安培免疫传感器研究

目的构建新型甲胎蛋白安培免疫传感器。方法首先在玻碳电极（GCE）表面修饰一层羧基化碳纳米管（CNTs）,然后利用带负电荷的DNA分子和带正电荷的硫堇之间的静电作用,层层自组装修饰硫堇以增强检测信号,然后利用硫堇的氨基固定纳米金,以便固定抗体,最后利用牛血清白蛋白封闭未结合位点。结果修饰的碳纳米管能够显著地提高电极的导电性,利用层层组装技术修饰了5层硫堇。在优化的条件下（pH7.0,温浴时间25min）,制作的甲胎蛋白免疫传感器线性范围在0.5～25ng/ml内,检测限0.02ng/ml。结论成功利用层层自组装技术构建新型基于碳纳米管修饰的无酶型甲胎蛋白安培免疫传感器,该传感器灵敏度高,特异性好,有望成为原发性肝癌早期诊断的新方法。

A study of a non-enzyme amperometric immunosensor for rapid detection of AFP based on carbon nanotubes modified glass carbon electrode

Objective To construct a novel amperometric immunosensor for the detection of alpha-fetoprotein（AFP）.Methods First,glass carbon electrode（GCE） was modified with multi-wall carbon nanotubes（CNTs）,and then the positively charged thionine,as the mediator,was immobilized by the negatively charged DNA through the layer-by-layer method.nano-Au was used to immobilized anti-AFP,and BSA was used to block any remaining active sites.Results Carbon nanotubes can significantly enhanced the electric conductivity of the electrode and was modified with 5 layers of thionine.With the optimized experimental parameters（pH 7.0,incubation time is 25 min）,the proposed immunosensor could detect AFP in a linear range from 0.5 to 25 ng/ml with a detection limit of 0.02 ng/ml at a signal-to-noise ratio of 3（S/D = 3）.Conclusion A non-enzyme amperometric immunosensor for Rapid Determination of AFP based on carbon nanotubes modified glass carbon electrode was successfully constructed through layer-by layer method and shows a good performance for determination of AFP.It provides a potential alternative tool for early diagnosis of primary liver cancer in clinical laboratory.