Hybrid recognition-enabled ratiometric electrochemical sensing of Staphylococcus aureus via in-situ growth of MOF/Ti3C2Tx-MXene and a self-reporting bacterial imprinted polymer

Rapid and effective analysis of foodborne bacteria is crucial for preventing and controlling bacterial infections. Here, we present the synthesis of a self-reporting molecularly imprinted polymer (MIP) as an inner reference probe (IR), and the in-situ growth of metal-organic frameworks on transition metal carbon nitrides (MOF/Ti3C2TX-MXene) as a signaling nanoprobe (SP). These advancements are then applied in a ratiometric electrochemical bioassay for Staphylococcus aureus (S. aureus) using a hybrid recognition mechanism. When S. aureus is present, the aptamer-integrated MIP (MIP@Apt) efficiently captures it, followed by binding with SP to form a sandwich structure. This leads to decreased current response of IR (IIR) and increased current intensity of SP (Isp), enabling quantification through utilization of the ISP to IIR ratio. The biosensor shows a wide detection range (10–108 CFU mL−1) and low detection limit of 1.2 CFU mL−1. Its feasibility for testing complex samples indicates the potential application in food analysis. •A self-reporting molecularly imprinted polymer was developed for ratiometric electrochemical detection of bacteria.•In-situ growth of MOF on Ti3C2Tx-MXene was proposed, demonstrating exceptional analytical performance.•This study introduced a novel hybrid recognition mechanism utilizing triple synthetic receptors.•The method successfully demonstrated its detection capability in 1-fold diluted complex matrices.