An immunosensor using a quartz Lamb wave device

A quartz Lamb wave device is applied to an immunosensor, where a surface mass change caused by an immunoreaction is detected as a phase difference change. The benefit of the Lamb wave device is the possibility of operation while immersed in a liquid. Mass change amplification by latex labeled antigens is also used for high sensitive detection. Mass sensitivity of the quartz Lamb wave device, which is made using an 80 μm thick quartz wafer, is about 0.56 degree/(1μm/cm2) at 4.5 MHz. The adsorption amount depends on the concentration of antigen in the sample solution. Concentrations from 0 μg/ml to 4 μg/ml are measured, which shows the Lamb wave device with mass change amplification is useful as an immunosensor.