共价固定乙肝表面抗体电容型免疫传感器研究

Studies on a Capacitive Hepatitis B Immunosensor Based on Covalently Immobilization Hepatitis Surface B Antibody onto Gold Electrode

利用硫脲中的硫原子和金之间强的共价效应，以及氨基与醛基的键合作用，将乙肝表面抗体（HBsAb）牢牢的固定在金电极表面。同时通过十二硫醇封闭电极，从而制得高灵敏、高稳定电容型乙肝表面抗原（HBsAg）免疫传感器。通过交流阻抗技术考察了溶液pS值和离子强度对电极性能的影响。结果表明：该免疫传感器操作简便，易于再生。电容响应与乙肝表面抗原浓度在7．5-750ng·mL^-1范围内呈线性关系，检出限为1．9ng／mL。

A new capacitive immunosensor was developed for direct determination of hepatitis B surface antigen （HBsAg） in human. Thiourea was initially self-assembled onto a gold electrode surface, and then hepatitis B surface antibody （HBsAb） molecules were eovalently immobilized on the thiourea molecules via the aid of glutaraldehyde （GA） crosslinking. To improve the insulation degree of the layer, the modified electrode was blocked with 1-dodecanethiol ethanol solution. The dependence of modified membrane stability on the pH and ion strength was studied with altemating current impedance. Under optimal conditions, the developed immunosensor exhibits high sensitivity and easy regeneration after immunoassay through washing with basic solution without obvious decrease in response. The linear calibration curve is obtained with a detection limit of 2.9ng/mL and a dynamic response range from 8 to 800ng/mL when plotted vs. the logarithm of the antigen concentration.