Piezoelectric

Abstract

A piezoelectric quartz crystal (PQC) based screening test for porcine reproductive and respiratory syndrome virus (PRRSV) infection in pigs is described. Gold-coated quartz crystals (10 MHz) were pre-modified by recombinant PRRSV protein. A direct assay format was employed to detect the presence of anti-PRRSV antibody in pig serum. Both dip and dry detection methods and static liquid-phase measurement approaches were adopted to perform the screening test and real time monitoring of molecule binding. Once the surface had been modified with antigen protein, only one sample incubation step of 5 min duration was required to provide frequency changes corresponding to the binding of the target antibodies. Serum samples from PRRSV infected pigs produced significant binding with the signal ranging from 100 to 400 Hz depending on the different titer, whereas samples from uninfected pigs produced no or minimal frequency changes of 0–60 Hz. The proposed PQC sensor can be used to screen pigs suspected to have been infected with PRRSV and to provide ‘yes’ or ‘no’ results. A total of 41 sera were detected. The results agreed well with those from licensed immunoassay.