Monitor of antibodies in human saliva using a piezoelectric quartz crystal biosensor

A piezoelectric quartz crystal immunosensor has been developed for the detection of antibodies in diluted human saliva. The system consists of the quartz piezoelectric crystal, oscillator and frequency counter. The antibodies against human immunoglobulin A are immobilized onto the gold electrode surface on the quartz crystal. The immobilization techniques used in this work are the adsorption method and the covalent bond method. The latter gives more stability in repetitive assays.