PREPARATION OF A PIEZOELECTRIC IMMUNOSENSOR FOR THE DETECTION OF SALMONELLA-PARATYPHI-A BY IMMOBILIZATION OF ANTIBODIES ON ELECTROPOLYMERIZED FILMS

To obtain new coatings for the preparation of piezoelectric immunosens ors, the anodic polymerization of o-aminophenol (oAP), o-phenylenediam ine (oPD) and m-phenylenediamine (mPD) onto a gold-plated crystal has been studied. The possibility of immobilizing an antibody (anti-S. par atyphi A) onto the crystal via the electropolymerized films was invest igated. The poly-mPD him gave the best results for immobilizing the an tibody. With antibodies crosslinked on the poly-mPD film, a piezoelect ric immunoassay for the detection of S. paratyphi A was proposed. The shift (Delta F = F-20s - F-400s, Hz) between the frequency at 20 s aft er the addition of sample (F-20s), and that of 400 s (F-400s) was used to construct a calibration graph, and shortening of the assay time wa s achieved. The S. paratyphi A concentration in the range of 10(5)-10( 9) cells/ml can be measured by this method.