PIEZOELECTRIC CRYSTAL FOR THE DETECTION OF IMMUNOREACTIONS IN BUFFER SOLUTIONS

The quartz-crystal microbalance (QCM) has been modified to allow for the monitoring of reactions in aqueous solution with about 10 ng sensitivity. This has been achieved by allowing only one electrode to be exposed to the solution of interest, the other being maintained in an air environment. When the gold electrodes of the QCM are thiol/diimide activated, they can be used to monitor the surface immobilization of immunoglobulin (IgG) molecules and their subsequent interaction with anti-IgG. This is demonstrated by immobilization of sheep or mouse IgG onto the thiolated electrodes, with preference shown for binding with anti-sheep and anti-mouse IgGs, respectively, during subsequent solution interaction. Some cross-reactivity occurs.