基于Au/SiO_2信号放大的人免疫球蛋白G电化学检测新方法

New Method of Electrochemical Immune Detection of Immunoglobulin G

将人免疫球蛋白G（人IgG）固定到导电玻璃ITO表面,利用抗原抗体有特异性结合制备出一种电化学免疫传感器。在导电玻璃ITO表面进行氨基化戊二醛修饰处理后,链接羊抗人IgG;在二氧化硅微球表面进行氨基戊二醛化,2~5nm纳米金通过静电吸附在二氧化硅微球表面,利用H2O2进一步将纳米金还原后粒径变大,链接羊抗人IgG。基于Au/SiO2信号放大效应,利用人IgG对羊抗人IgG的特异性结合作用,人IgG分别与导电玻璃端和纳米材料端相结合,形成三明治夹心结构,建立了一种检测人IgG的电化学免疫新方法。电极表面的氧化还原峰电流值与人IgG的浓度在1~200ng/mL内呈良好的线性关系,线性回归方程为y=-0.5326x＋409.2567,相关系数R2=0.9948,检测限为0.6ng/mL。该电化学免疫传感器实现了对人免疫球蛋白G低成本、超灵敏的检测,有望应用于人体血清检测。

To develop a novel electrochemical immune biosensor based on antigen-antibody reaction with the immunoglobulin G immobilized the surface of the ITO. The side of ITO was immobilized the goat anti-human IgG after the amino-modified and glutaraldehyde modification.The side of SiO2 also had the same modification of amino and Glutaraldehyde,and then 2 ~5 nm gold nanoparticles adsorbing the surface of SiO2 by the use of electrostatic interaction. We immobilized the goat anti-human IgG after the reduction of H2O2 with bigger gold nanoparticles.When human IgG respectively combined with the ITO and nanomaterials,it would form the sandwich structure of a new detection of immunoglobulin G based on Au/SiO2 to amplify signal amplification. The prepared biosensor showed a excellent linearity relationship of Cyclic voltammograms current value and the concentration of immunoglobulin G 1 ~200ng/mL,the equation of linear regression is y=-0.532 6x＋409.256 7（R2=0.994 8）,with a detection limit of 0.6ng/mL. The established method is low cost and ultrasensitive,and can be used to detect immunoglobulin G.