PIEZOELECTRIC CRYSTAL FOR THE DETECTION OF IMMUNOREACTIONS IN BUFFER SOLUTIONS

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