Simultaneous immunoassay using piezoelectric immunosensor array and robust method

A simultaneous immunoassay technique has been developed for the determination of dual analytes, immunoglobulin M (IgM) and C-reactive protein (CRP) by constructing a piezoelectric quartz crystal array system. This array system was composed of five piezoelectric quartz crystals. Each crystal was immobilized with an antibody mixture, which had a fixed ratio of anti-IgM to anti-CRP antibodies but worked under different detection conditions, i.e., in five buffer media with different pH values. The specificity of immunoreactions and the effect of pH on the sensitivity of the immunosensors were investigated. Applications of this array system in the estimation of the concentration of unknown samples using three linear regression methods, i.e., ordinary least squares (OLS), partial least squares (PLS) and least terminated squares (LTS), were presented. Results of these samples showed that the LTS estimator is a promising tool for multi-analyte piezoelectric immunoassay.