摘要

An amperometric immunosensor is described for the assay of antibody of Schistosoma japonicum (SjAb). The polyanionic perfluorosulfonated Nation polymer was used to modify the glassy carbon electrode as a platform for the immobilization of S. japonicum antigen (SjAg). The competitive immunoassay format was employed to detect SjAb with horseradish peroxidase (HRP)-SjAb as a tracer, o-aminophenol (o-AP) and hydrogen peroxide as enzyme substrates. The amount of HRP-labeled SjAb binding onto the electrode surface was detected by measuring the product of the enzyme catalytic reaction at -250 mV (versus Ag/AgCl reference electrode). The system was optimized with regard to parameters involved in the preparation of immunosensor and the assay process. The present immunosensor permits a reliable determination of SjAb in the range of 0.05-4.8 mug/ml with a relative standard deviation of below 7.4%. The rabbit serum samples of different infection degree were measured, which implied the immunosensor offer a promising alternative for clinical diagnosis of S. japonicum.