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pH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7.5～750
ng.mL-1范围内呈线性关系,检出限为1.9 ng/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
covalently immobilized on the thiourea molecules via the aid of
glutaraldehyde(GA) cross-linking.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 alternating 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.
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