Temporal sensing platform based on anodic dissolution of Ag and cathodic biocatalysis of oxygen reduction for Staphylococcus aureus detection

An Ag@C hybrid bipolar electrode (BPE) sensing platform has been established for the temporal detection of Staphylococcus aureus (S. aureus) in food. Combining the advantages of anodic dissolution of Ag and cathodic biocatalysis of oxygen (O-2) reduction, this strategy showed an ultralow detection limit down to 10 CFU mL(-1). As the formation of Ag@C completely quenched the electrochemiluminescence (ECL) emission of luminol, the ECL emission recovery reflected the extent of anodic dissolution. Meanwhile, S. aureus catalyzed the electrochemical reduction of O-2 at the cathode, reducing the overpotential for cathodic O-2 reduction and thus increasing the rate of anodic electron loss, facilitating Ag dissolution and restoring the ECL emission of luminol. When a constant potential was applied, through monitoring the ECL recovery time before and after the incubation of S. aureus on the cathode, S. aureus could be quantified due to the slight difference of the conductivity.

Automated summary

An Ag@C hybrid bipolar electrode sensing platform has been established for the detection of Staphylococcus aureus in food. This platform combines the advantages of anodic dissolution of Ag and cathodic biocatalysis of O-2 reduction, achieving an ultralow detection limit and quantification of S. aureus.