【摘要】 用蛋白质修饰的金纳米颗粒作为探针,采用树枝状放大途径,结合石英晶体微天平(QCM)技术对人免疫球蛋白G(IgG)进行检测。通过在QCM的金电极表面组装一层蛋白A将羊抗人IgG抗体固定于传感界面用以捕获分析物IgG。利用纳米金标记的抗体和由金标抗体及金标蛋白A构成的免疫复合物分别作为一级放大标记物和二级放大标记物,可以显著放大抗原-抗体的识别信号。用QCM对金标抗体和胶体金免疫复合物的放大过程进行了连续监测。对金标抗体的稀释倍数和复合物的组成进行了优化。一级放大和二级放大的频率信号与人IgG浓度在10.9 μg/L～10.9 mg/L范围内呈良好的线性关系,经过二级放大后,用QCM可检测低至3.5μg/L的IgG。更多还原

【Abstract】 A novel method to amplify antigen-antibody recognition event by the application of protein-functionalized Au-nanoparticles as amplifying probes and a dendritic-type amplification route for microgravimetric quartz crystal microbalance (QCM) immuno-sensing has been developed. Goat anti-human immunoglobulin G (IgG) antibody is immobilized on the Au electrode surface of QCM through pre-assembled protein A and acts as the sensing interface to capture the analyte, human IgG. The recognition event is amplified by the primary amplification process, i.e., interaction of the resulting interface with the colloidal gold-labeled antibody, and the secondary, dendritic-type amplification process, i.e., interaction with the colloidal gold immunocomplex consisting of the colloidal gold-labeled antibody and the colloidal gold-labeled protein A. The binding of the colloidal gold-labeled antibody with the sensing interface and the dendritic-type amplified sensing process are monitored continuously by QCM in phosphate buffer solution. The dilution ratio of colloidal gold-labeled antibody and the component of immunocomplex are optimized. The frequency changes of the primary amplification and the secondary amplification process depend linearly on the IgG concentration over the range of 10.9μg/L to 10.9mg/L. As low as 3.5μg/L of the IgG can be detected by QCM through the dendritic-type amplification route.更多还原