Nanozymatic degradation and simultaneous colorimetric detection of tetracycline

Tetracycline (TC) is a broad-spectrum antibiotic that can enter and accumulate in the human body via the food chain. Even in small concentrations, TC can cause several malignant health effects. We developed a system to simultaneously degrade the presence of TC in food matrices using titanium carbide MXene (FL-Ti₃C₂T_x). The FL-Ti₃C₂T_x exhibited biocatalytic property that activates hydrogen peroxide (H₂O₂) molecules in 3, 3', 5, 5'-tetramethylbenzidine (TMB environment. During the FL-Ti₃C₂T_x reaction, the catalytic products released turn the color of the H₂O₂/TMB system bluish-green. However, when TC is present, the bluish-green color does not appear. Via quadrupole time-of-flight mass spectrometry, we found that the TC is degraded by FL-Ti₃C₂T_x / H₂O₂ in preference to H₂O₂/TMB redox reaction, which intervenes in the color change. Hence, we developed a colorimetric assay to detect TC with a LOD of 615.38 nM and proposed two TC degradation pathways that facilitate the highly sensitive colorimetric bioassay.