The intrinsic enzyme mimetic activity of platinum oxide for biosensing of glucose

Given the enzymatic properties and the oxidized surface of Pt nanomaterials, we demonstrated the intrinsic oxidase-like and peroxidase-like activities of platinum oxide (PtO₂). The surface clean PtO₂ nanoparticles with high water dispersibility were synthesized by a simple and green method. X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) results demonstrated that the prepared PtO₂ nanoparticles mainly consisted of Pt (Ⅳ) state without Pt(0) chemical state. The enzymatic activity of PtO₂ nanoparticles was verified by catalytic oxidation of several chromogenic substrates. Catalytic mechanism analysis suggested that PtO₂ nanopartiles acted as peroxidase and oxidase enzyme mimics by promoting the generation of the reactive oxygen species (ROS). By combining glucose oxidase, a colorimetric assay for glucose detection was developed with the limit of detection of 10.8 μM. The successful application of the proposed detection assay in human serum samples demonstrated the promising practical application in clinical diagnosis, pharmacy and food.