Multifunctional BiomimicCopper Nanozyme as Glucose and Hydrogen Peroxide Biosensor

In recent years, nonenzymatic electrochemical nanozymes have attracted significant attention for biomarker sensing. In this work, Cu/Cu₂O/CuO heteronanostructure-based nanozymes were successfully synthesized via a simple one-pot hydrothermal method for the noninvasive detection of glucose and hydrogen peroxide. The structural composition and morphology of the copper-based nanozymes have been thoroughly characterized by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). Notably, our tailored synthesis strategy enables the formation of multiple copper oxidation states in an ultrathin surface layer covering bulk copper nanoparticles. This heteronanostructure surface enhances the material stability and creates efficient electron-transfer pathways for glucose and hydrogen peroxide sensing. Furthermore, without using any surfactant, the surface composition of the Cu/Cu₂O/CuO nanozymes can be precisely tuned by controlling the synthesis conditions in a single-step reaction. Electrochemical studies reveal that the in situ formation of a copper hydroxide layer on metallic copper significantly enhances sensing performance. The prepared copper-based sensor shows a wide linear detection range of 10 nM-2.8 mM for glucose and 10 nM-14 mM for hydrogen peroxide, with low detection limits of 764 nM and 87 nM, respectively. We have also demonstrated the feasibility of our proposed sensor in detecting glucose and hydrogen peroxide in real samples. These results highlight the strong potential of Cu/Cu₂O/CuO nanozyme as a nonenzymatic electrochemical sensing platform for glucose and hydrogen peroxide.