摘要
提出一种基于酶催化沉积底物和生物素——亲和素两步放大的超灵敏免疫检测方法.抗体通过单层蛋白A固定到金电极表面,预先处理好的生物素化抗体和辣根过氧化物酶(HRP)标记的亲和素形成的网状复合物作为免疫反应信号的放大探针.在有H2O2存在的情况下,通过辣根过氧化物酶(HRP)催化氧化DAB(3,3’—联苯二胺)在金电极上沉积一层不溶物,引起阻抗的显著增大.该传感器用于人IgG检测,检测下限为1.0×10-8g.采用法拉第阻抗和压电石英晶体微天平分别表征了该传感器的特性.
An amplified immunoassay with improved sensitivity has been proposed based on two - step amplifieation procedures of enzyme - catalyzed precipitation and biotin - streptavidin binding system. Anti - IgG antibody is mobilized onto the surface of gold electrode modified with a thin layer of protein A. Biotin labeled anti - IgG antibody and HRP - streptavidin are premixed to form network complex to be used as probes for amplifying the sensing response of antibody - antigen interaction. HRP biocatalyzes DAB ( 3,3'- diaminobenzidine) in the presence of, resulting in an insoluble product on the electrode surface, to achieve an enhanced electron - transfer resistance on the electrode surface as well as a decreased frequency. The results show that this method can greatly improve the detection sensitivity of IgG in human serum with concentration as low as 1. 0 ×10^- 8 gmL^-1. We employe Faradaic impedance spectroscopy and quartz crystal microbalance (QCM) to follow the stepwise assembly of the systems and investigate immunosensing properties.
出处
《宁德师专学报(自然科学版)》
2007年第4期357-361,共5页
Journal of Ningde Teachers College(Natural Science)
关键词
生物传感器
酶催化沉积放大
生物素——亲和素
biosensors
biocatalyzed precipitation
biotin - streptavidin binding system