A Label-free Immunosensor Based on K3[Fe(CN)6] and Aldehyde-Functionalized Pyridinium
- 2018年第24卷 
采用聚二烯丙基二甲基氯化铵(PDDA)将铁氰化钾电子媒介体固定在电极表面，构建免标记的电化学免疫传感器. 醛基吡啶盐不仅作为基底物质直接固定抗体，还可以很好地增强电极表面的导电性能. 将构建的传感器用于肿瘤标志物甲胎蛋白的检测. 其线性范围为0.01-20 ng·mL-1，检测下限为0.004 ng·mL-1（3 S/N）. 此传感器的构建简单方便、无标记、特异性好，为甲胎蛋白及其他肿瘤标志物提供了新的检测方法.A novel aldehyde-functionalized pyridinium was successfully synthesized. Using K3[Fe(CN)6] as a redox species modified on the surface of the electrode through Poly(diallyldimethylammonium chloride), we developed a label-free immunosensor based on aldehyde-functionalized pyridinium that was applied to simplify antibody immobilization on the electrode surface, in which no additional chemical cross-linking was required. In addition, the introduction of K3[Fe(CN)6] on the surface of electrode avoided the use of other redox species in the electrolyte solution. Under the optimal experimental conditions, differential pulse voltammetry (DPV) signals corresponding to different α-Fetoprotein (AFP) concentrations were measured. After antigens with different concentrations reacted with antibodies immobilized on the electrode surface, the peak current of DPV gradually decreased with increasing concentrations of AFP. The calibration curve showed a good linear relation in the range from 0.01 to 20 ng·mL-1 with the linear regression equation of y = -3.23x + 22.42 (R2=0.9943). The detection limit is 0.004 ng·mL-1 based on a signal-to-noise ratio of 3. The constructed immunosensor is simple, label-free and specific, thus, provides a good diagnostic tool for detection of α-Fetoprotein and other cancer markers.