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

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 (Km). 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.