Chen Jin, Yan Feng, Dai Zong, Ju Huangxian
Key Laboratory of Analytical Chemistry for Life Science, Education Ministry of China, Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
Biosens Bioelectron. 2005 Aug 15;21(2):330-6. doi: 10.1016/j.bios.2004.10.023. Epub 2004 Dec 8.
A novel amperometric immunosensor for determination of human serum chorionic gonadotrophin (HCG) was constructed by immobilization of HCG with titania sol-gel on a glassy carbon electrode and the direct electrochemistry of horseradish peroxidase (HRP) labeled to HCG antibody (HRP-anti-HCG). The morphologies of the HCG membrane were characterized to be chemically clean, porous and homogeneous. HRP-anti-HCG was functionally conjugated with the immobilized HCG after incubation in phosphate buffer (PBS) containing HRP-anti-HCG. A direct electron transfer of HRP with a rate constant of 1.35+/-0.40 s(-1) was observed at the HRP-anti-HCG-HCG/titania sol-gel membrane modified electrode in 0.1 M PBS pH 7.0. With a competitive mechanism the differential pulse voltammetric peak current of the immobilized HRP decreased linearly with an increasing HCG concentration from 2.5 to 12.5 mIU/ml in the incubation solution. The HCG immunosensor showed a detection limit of 1.4 mIU/ml, a good accuracy and acceptable precision and reproducibility with an intra-assay CV of 4.7% at 5.0 mIU/ml and an inter-assay precision of 8.1% obtained at 10 mIU/ml. The biosensor displayed a good stability in a storage period of 30 days.
通过用二氧化钛溶胶 - 凝胶将人绒毛膜促性腺激素（HCG）固定在玻碳电极上，并利用标记有辣根过氧化物酶（HRP）的HCG抗体（HRP - 抗HCG）的直接电化学，构建了一种用于测定人血清绒毛膜促性腺激素（HCG）的新型安培免疫传感器。对HCG膜的形态进行表征，结果表明其化学纯净、多孔且均匀。在含有HRP - 抗HCG的磷酸盐缓冲液（PBS）中孵育后，HRP - 抗HCG与固定化的HCG发生功能结合。在0.1 M pH 7.0的PBS中，在HRP - 抗HCG - HCG/二氧化钛溶胶 - 凝胶膜修饰电极上观察到HRP的直接电子转移，速率常数为1.35±0.40 s⁻¹。基于竞争机制，在孵育溶液中，固定化HRP的差分脉冲伏安峰电流随着HCG浓度从2.5增加到12.5 mIU/ml而线性下降。该HCG免疫传感器的检测限为1.4 mIU/ml，具有良好的准确性和可接受的精密度与重现性，在5.0 mIU/ml时批内变异系数为4.7%，在10 mIU/ml时批间精密度为8.1%。该生物传感器在30天的储存期内表现出良好的稳定性。
