非标记型河虾免疫传感器的制备及应用

Preparation of a non-labeled river shrimp antibody immunosensor and its application

四乙氧基硅在HCl催化下水解形成硅溶胶。将硅溶胶与河虾抗体混合均匀后,涂于玻碳电极表面制备得非标记型河虾抗体免疫传感器。采用Fe（CN）6^3-/4-的磷酸盐缓冲溶液（pH 6.5）为测试底液,研究此传感器在免疫反应中的循环伏安和交流阻抗特性。结果显示免疫反应后传感器的循环伏安图上未出现新的氧化-还原峰,表明该免疫反应属于非氧化还原过程。采用交流阻抗监测电极表面,发现传感器阻抗值随虾过敏原浓度的增加而增大。对交流阻抗图进行分析,结果表明电极表面的免疫反应是一个受电子转移控制的过程。当虾过敏原浓度在0-10 ng/mL之间,电极表面电子转移阻抗的增加值与虾过敏原浓度呈线性关系,检出限为0.1 ng/mL（S/N=3）。该方法已成功应用于河虾制品中过敏原的测定。

Tetraethoxysilicane was hydrolyzed into silica sol in the presence of hydrochloric acid. After that, a non-labeled immunosensor was fabricated by dripping the mixture of the silica sol ane river shrimp antibody on the surface of the glassy carbon electrode. In this study, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS） were employed to investigate the electrochemical performance of immunoreaction of river shrimp allergen with the antibody, in which the sensor and Fe（ CN）6^3-/4- phosphate buffer solution （pH 6.5） was empolyed as the working electrode and the base solution for test, respectively. During the immunoreaction, no new peak in CV plot was observed, this indicated the immunoreaction was a non redox process. However, the electron transfer resistance of the sensor increase linearly with increasing the concentration of river shrimp allergen in the EIS plot. Basing on analysis of the EIS plot, the reaction on the sensor surface is an electron transfer limited process. The electron transfer resistance of the sensor increases linearly with the increase of river shrimp allergen from 0 to 10 ng/mL, and the detection limit is 0.1 ng/mL （S/N = 3）. The proposed method has very good sensitivity and stability, and it was successfully applied to the determination of river shrimp allergen content in several food samples.