A piezoelectric immunoassay based on nanoprobe immunoagglutination was proposed for rapid and sensitive detection of IgG. The nanoprobes were prepared by labeling gold nanoparticles with anti-IgG antibody. And a piezoelectric sensor was used to monitor the changes in solution density and viscosity caused by the immunoagglutination of IgG and anti-IgG nanoprobes. The effects of pH and ionic strength were investigated. It is found that the developed immunoagglutination assay is sensitive to IgG with the detection limit of 1.12, 0.72, 0.70 nmol/L to the detection time of 10, 20, 30 min, respectively, and it is unnecessary for immobilization of immunoactive entities.
