Label-free electrochemical immunosensor based on an internal and external dual-signal synergistic strategy for the sensitive detection of Salmonella in food

The prevention of foodborne pathogens has been a significant aspect of food safety. Among these pathogens, Salmonella stands out as one of the most representative strains, and the prevention of its contamination is paramount for protecting food safety. Here, we successfully developed an electrochemical immunosensor based on the synergistic amplification of internal and external dual signals for the rapid detection of Salmonella in food. The Fe3O4@Prussian blue (PB) core-shell nanomaterial, synthesized via the in-situ generation of PB on the Fe3O4 surface through acid etching, exhibited good stability and redox activity, enabling its integration with [Fe(CN)6]3−/4− ionic tags for dual-signal synergistic amplification of current signals. The microstructure and elemental composition of the Fe3O4@PB core-shell nanomaterial were analyzed using relevant instruments. In optimal conditions, this strategy demonstrated a broad detection range from 7.375 × 101 to 7.375 × 107 CFU mL −1, with a low detection limit of 9.912 CFU mL −1. Furthermore, the sensor we developed shows good stability, excellent selectivity, and reproducibility, and has great application potential in the detection of foodborne pathogens.