Characterization of immobilization methods for African swine fever virus protein and antibodies with a piezoelectric immunosensor

A direct piezoelectric flow injection analysis immunoassay for the detectio n of African Swine Fever virus and antibodies is presented. The peptide-spe cific monoclonal antibody 18BG3 and the virus protein 73 were used for dete ction with a quartz crystal microbalance. Accumulation of the analyte on th e surface of this mass-sensitive biosensor resulted in a shift of the reson ant frequency. Highly selective receptor layers were applied on the sensing electrode of the quartz crystal for detection of the complementary analyte . Different immobilization methods proved to be appropriate for coating of the monoclonal antibody 18BC3. A quartz crystal covalently coated with the antibody 18BG3 detected virus protein VP73 samples more than 20 times and w as stable for more than 30 days. The coating of virus protein was performed by physisorption. A sensor with a virus protein receptor layer detected an tibody 18BG3 samples 10 times within one day. The sensor device was able to perform one measurement cycle including blocking and regeneration within 3 0 min. With the help of a suitable carrier liquid, measurements with serum samples were performed. The calibration curves for measurements in buffer a nd in serum could be determined and the detection limits for virus protein detection were 0.31 and 1 mu g/ml, and for antibody detection 0.1 and 0.2 m u g/ml respectively. (C) 1998 Elsevier Science S.A. All rights reserved.