A dual-stimuli responsive electrochemiluminescence biosensor for pathogenic bacterial sensing and killing in foods

Pathogenic bacterial contamination of food-associated products threatens food safety. Herein, a dual-stimuli responsive electrochemiluminescence (ECL) sensor was constructed for the determination and sterilization of Staphylococcus aureus (S. aureus). Silver nanoclusters labeled hairpin DNA (H-Ag NCs) acted as the energy acceptor of ECL emission from CdS quantum dots (CdS QDs), generating resonance energy transfer (RET) and quenching ECL signal. After activation of DNA walker by S. aureus and cleavage of nicking endonuclease, Ag NCs were liberated from CdS QDs surface, and then gold nanoparticles (Au NPs) were introduced. ECL signal was enhanced by the energy transfer from ECL-excited surface plasmon resonance (SPR) in Au NPs to CdS QDs. Consequently, the proposed method performed well in S. aureus test with a linear range of 5-108 CFU/mL. This sensing system achieved the high discrimination and killing of S. aureus in foods, illuminating the reliability in practical applications.