通过抗原抗体的特异性识别作用以及金纳米簇(AuNCs)探针和金标银染的双重信号放大作用,构建了一种新的电化学免疫传感器,对人的免疫球蛋白(IgG)进行了检测.受贻贝分泌的黏附蛋白启示,首先将聚多巴胺薄膜修饰在铟锡氧化物电极(ITO)上,并对一抗抗体进行固定,通过观察电化学阻抗的变化来监控免疫传感器的构建过程.将待检测的IgG抗原组装在该电极上并与AuNCs标记的二抗反应,最后经银染反应,用溶出伏安法对IgG的含量进行定量检测,其灵敏度达到0.5 ng/L.该方法可应用于实际血清样品中IgG含量的测定.
A cheap and portable electrochemical immunosensor based on silver-enhanced colloidal gold electrochemical stripping technique and gold nanoclusters (AuNCs) labels was proposed for the detection of human IgG. Inspired by the adhesive proteins that secreted by marine mussels, the stable and robust film-poly (dopamine) was used to immobilize biomolecules (Ab1 ) on an indium tin oxide (ITO) electrode for the fabrication of immunosensor. Then, human IgG and AuNCs-Ab2 were successively immobilized to the Ab1 modified ITO electrode. The process for the fabrication of sandwich immunosensor was monitored by electrochemical impedance spectroscopy. Through the immunoreaction between antigen and antibody, IgG could be quantitatively determined by anodic stripping vohammetry. On the basis of the dual signal amplification of AuNCs labels and silver enhancement technique, the sensitivity was improved to 0.5 ng/L. Moreover, the proposed immunosensor could be used in clinical diagnosis.