A three-in-one hybrid nanozyme for sensitive colorimetric biosensing of pathogens

Pathogen screening is an important step in preventing foodborne diseases . In this study, a hybrid nanozyme, metal organic framework decorated with palladium (Pd) and platinum (Pt) ( [email protected] /Pt), was innovatively synthesized and used with immune magnetic nanobeads (MNBs) for sensitive biosensing of Salmonella . First, immune [email protected] /Pt nanozymes and immune MNBs were mixed with target pathogens in a large-volume sample, resulting in effective isolation and specific label of target pathogens to form nanobead- Salmonella -nanozyme conjugates. Then, these conjugates were used to catalyze H 2 O 2 -TMB, and its color was changed from colorless to blue. Finally, catalysate absorption was measured to determine pathogen concentration. This colorimetric immunoassay could determine Salmonella typhimurium from 4 × 10 1 to 4 × 10 5 CFU/mL in 60 min with a detection limit of 32 CFU/mL.