Ultrasensitive detection of staphylococcal enterotoxin B in foodstuff through dual signal amplification by bio-barcode and real-time PCR

Abstract This study developed an ultrasensitive method involving (1) gold nanoparticles encoded with a double-stranded DNA as the first signal amplification and goat anti-staphylococcal enterotoxin B (SEB) polyclonal antibody and (2) magnetic microparticles coated with anti-SEB monoclonal antibody to detect SEB. Both functionalized nanoparticles can capture SEB in a sandwich system. The released DNA barcodes were then characterized through SYBR Green real-time polymerase chain reaction and resulted in the second signal amplification. Under optimized experimental conditions, an ultrasensitive bio-barcode for SEB detection was established, and its detection limit could reach 0.269 pg mL −1 , which was 1000-fold lower than that of conventional enzyme-linked/immunosorbent assay. The proposed method shows great potential in food security.