Nanozyme-Mediated Catalytic Signal Amplification for Microfluidic Biosensing of Foodborne Bacteria

Early detection of foodborne bacteria is urgently needed to ensure food quality and to avoid the outbreak of foodborne bacterial diseases. Here, a kind of metal-organic framework (Zr-MOF) modified with Pt nanoparticles (Pt-PCN-224) was designed as a peroxidase-like signal amplifier for microfluidic biosensing of foodborne bacteria. Taking Escherichia coli (E. coli) O157:H7 as a model, a linear range from 2.93 × 10² to 2.93 × 10⁸ CFU/mL and a limit of detection of 2 CFU/mL were obtained. The whole detection procedure was integrated into a single microfluidic chip. Water, milk, and cabbage samples were successfully detected, showing consistency with the results of the standard culture method. Recoveries were in the range from 90 to 110% in spiked testing. The proposed microfluidic biosensor realized the specific and sensitive detection of E. coli O157:H7 within 1 h, implying broad prospects of MOF with biomimetic enzyme activities for biosensing.