Copper oxide nanosheets as an effective nanozyme with haloperoxidase-like activity for the colorimetric detection of H2O2 and glucose

Copper oxide nanosheets (CuO NSs) have been successfully obtained by exploiting an effective one-step approach of sugar-blowing method followed by calcination. The nanosheets were characterized by several techniques like X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Impressively, CuO NSs display haloperoxidase (HPO) like catalytic activity which catalyses the oxidation of chloride ions by H 2 O 2 giving rise to reactive chlorine species (RCS). A sensitive and selective colorimetric sensor was then demonstrated via the oxidation of chromogenic substrate 3,3 ' ,5,5 ' - tetramethylbenzidine (TMB) by the novel nanoenzyme CuO NSs through the generation of RCS for H 2 O 2 and glucose detection with limit of detection of 109 nM and 21 nM in the linear ranges of 4.6 mu M to 769 mu M and 0.22 mu M to 19.57 mu M respectively. Additionally, the methodology is validated for the analysis of glucose in real samples.