Aromatic Amino Acid Dipeptide-Mediated Bacterial Imprinted Electrochemiluminescence Sensor with Cytochrome-Accelerated Electron Transfer for Ultrasensitive Detection of Staphylococcus aureus

In this study, a novel biosensing platform based on aromatic amino acid dipeptide-boosted bacterial imprinted electrochemiluminescence technology was successfully constructed for the efficient detection of Staphylococcus aureus. The sensor employs copper/europium metal–organic frameworks (Cu/Eu-MOFs) as the ECL substrate, demonstrating excellent and stable luminescence. Notably, the aromatic dipeptide Cyclo(-Gly-Trp) was used as a functional monomer, primarily binding to cytochrome P450 in S. aureus membrane proteins via hydrophobic interactions. This interaction facilitates NADPH-dependent electron transfer, activating subsequent electron transport (ET) pathways and significantly accelerating charge transfer in this region. As well, comparative studies confirmed that the aromatic dipeptide substantially enhances electron transfer, leading to a stronger ECL signal than systems lacking aromatic amino acids. With good linearity in the range of 101–108 CFU/mL and a detection limit as low as 3.36 CFU/mL (S/N = 3), this sensor provides an innovative solution for rapid screening of food-contaminated microorganisms with the advantages of high specificity and ease of operation.