Iron-doped tungsten disulfide nanozyme with peroxidase-like activity for hydrogen peroxide (H₂O₂) and glucose...

Objectives: To fabricate iron-doped WS₂ (Fe-WS₂) nanozymes with prominent peroxidase-like (POD-like) activity and explore their application in biomolecule detection. Methods: Fe-WS₂ nanozymes were synthesized via a hydrothermal method, and their structural and chemical properties were characterized. The POD-like activity of the Fe-WS₂ nanozymes was evaluated at different pH, temperatures, and substrate concentrations. Kinetic parameters were determined using the Michaelis-Menten equation. The detection capabilities of the Fe-WS₂ nanozymes for H₂O₂ and glucose were assessed through colorimetric assays. Results: The synthesized Fe-WS₂ nanozymes exhibited a uniform size distribution with an average diameter of approximately 300 nm. The successful loading of iron ions onto the WS₂ nanosheets was confirmed by mapping and energy-dispersive X-ray spectroscopy analyses. The Fe-WS₂ nanozymes demonstrated enhanced POD-like activity compared to unloaded WS₂ nanozymes, as evidenced by the increased oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H₂O₂. The optimal conditions for POD-like activity were found to be at pH 4 and 55 °C. Kinetic analysis revealed that the Fe-WS₂ nanozymes had a high affinity for both H₂O₂ and TMB, with low Michaelis constants (K_m). The Fe-WS₂ nanozymes-based colorimetric assay exhibited a wide linear range (0.2 to 1 mM) for H₂O₂ detection, with a low detection limit of 7.27 × 10^-7 M. For glucose detection, the assay showed good selectivity and sensitivity, attributed to the specificity of glucose oxidase in catalyzing glucose oxidation. Conclusions: This study successfully developed Fe-WS₂ nanozymes with remarkable POD-like activity, which were utilized to construct a sensitive and specific colorimetric biosensing system for the detection of H₂O₂ and glucose. The results indicate that the Fe-WS₂ nanozymes have great potential for applications in biomedical diagnostics due to their high catalytic efficiency, stability, and excellent biocompatibility. This work not only provides a novel inorganic nanozyme biosensor but also opens up new avenues for the application of other nanozyme biosensors in the biomedical field.