One-Pot Electrochemical Biosensor Combining a Magnetite/Gold Modified Electrode and the Strand Displacement Reaction for Sensitive Determination of Escherichia coli

The application of electrochemical biosensors for detecting foodborne pathogenic bacteria offers benefits like user-friendly, rapid, cost-effective, and portable operation. While screen-printed carbon electrodes (SPCEs) show promise, their rough surfaces and poor stability issues hinder sensitive detection. Here, SPCEs were modified with Fe3O4 and Au nanoparticles to enhance electron transfer. Combined with a chain displacement reaction, a one-pot electrochemical biosensor was developed. It exhibits good reproducibility and stability, detecting Escherichia coli (E. coli) 16S rRNA down to 10−12 M and discriminating single-base mismatches. The biosensor successfully detected E. coli in spiked milk samples, demonstrating its potential for foodborne pathogens detection.