Quartz crystal microbalance assay for determination of plasma vitellogenin

Anti-vitellogenin antibody was immobilized on a quartz crystal oscillator and applied to a quartz crystal microbalance (QCM) for detection of plasma vitellogenin (Vtg) of fish. The QCM exhibited a significant decrease in frequency responding to Vtg addition. The association constant K for the antigen-antibody reaction was determined to be 7 × 107 M−1. The QCM was also sensitive to plasma from Koi carp (Cyprinus carpio), of which Vtg synthesis had been stimulated by injection of estradiol-17β. Although nonspecific response to components in the plasma was observed, it was suppressed by pretreatment of the QCM device with bovine serum albumin.