Engineered nanozymes for speedy colorimetric biosensing and sensitive cascaded-catalytic determining of norfloxacin

Nanozymes based on default engineering have garnered considerable interest for their ability to effectively imitate natural enzyme catalysis settings for detection. With the widespread use of quinolone antibiotics, it is worth noting that the antibiotic drugs represented by norfloxacin (NOR) are concentration-dependent when used. Therefore, residual or dosage differences in the body can lead to some central toxicity hazards, so monitoring and detection are necessary. Herein, we reported Fe3O4@MIL-101@polypyrroles (PPys) nanozymes with default engineering, which possessed a porous core–shell structure with Fe3O4 as the core and MIL-101 and PPys as the shells in sequence. X-Ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculation were to guide and analyze the catalytic pathway of peroxidase-like activity. Furthermore, a versatile intelligent colorimetric and sensing platform has been established to achieve sensitive cascaded-catalytic determining norfloxacin (NOR). In addition, NOR has a lower threshold of acceptability detection of 0.14 μM, which is better than the interpreted detection methods. We have firstly explored the detection mechanisms of ascorbate (H2A) and NOR and discovered that NOR could selectively oxidize Fe2+ and support Bi-Bi mechanisms in the process of H2O2 catalysis. Excellent guidelines for the design of multifunctional nanozyme catalysts were provided by the inquiry.