Abstract: Based on plasma-polymerized film(PPF) and polyelectrolyte, a novel piezoelectric immunosensor is developed for the determination of transferrin in human serum. The approach begins with the preparation of PPFon the surface of quartz crystal microbalance(QCM) by the glow-discharge. Through strong electrostatic attraction, a negative-charged polyelectrolyte which serves as a removable layer for the QCMreproduction is then self-assembled on the film, and positive-charged antibodies which specifically react with antigens are subsequently immobilized on the self-assembled layer by controlling the pHvalue. The effects of experimental conditions including the self-assembly of polyelectrolyte, the incubation of transferrin antibodies and the test of immunoreaction are discussed, respectively. In addition, the sensitivity, selectivity, regeneration and reproducibility of the immunosensor are investigateDIn detail. Under the optimal experimental conditions, the QCM immunosensor can be used to determine quantitatively transferrin in human serum with the linear range of 0.10-12.65 μg/mL. It is found that the results of clinical samples by this developed method are identical to those by the ELISAmethod.

Key words: Plasma polymerized film, Polyelectrolyte, Transferrin, Piezoelectric immunosensor