High-performance electrochemical biosensor comprising Mn-ZIF-67 conjugated with anti-O antibody for Escherichia coli...

The detection of Escherichia coli (E. coli) in food and water is critical for public health, yet existing methods often lack sensitivity, speed, or field applicability. Here, we develop an electrochemical biosensor based on Mn-doped Co zeolitic imidazolate framework (ZIF-67) functionalized with anti-O antibody for sensitive E. coli detection. Mn incorporation induces phase reconstruction, surface area enhancement, and electron transfer. Antibody conjugation modulates wettability, introduces amide I and II vibrational modes, and selectively blocks electron transfer upon bacterial binding. The biosensor exhibits a linear range of 10 to 10¹⁰ CFU mL^-1 with a 1 CFU mL^-1 detection limit, outperforming optical and other metal organic framework-based sensors. It can discriminate non-target bacteria (Salmonella, Pseudomonas aeruginosa, Staphylococcus aureus), maintain >80% sensitivity over 5 weeks, and recover 93.10 -107.52% E. coli spiked in tap water. This work suggests the tremendous potential for on-site pathogen monitoring.