Fluorescent hydrogen peroxide sensor based on cupric oxide nanoparticles and its application for glucose and l-lactate detection

A novel fluorescent hydrogen peroxide sensor was developed based on the peroxidase-like activity of cupric oxide nanoparticles. Cupric oxide nanoparticles effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. The linear range of hydrogen peroxide estimated to be 5.0×10−6-2.0×10−4 M with a detection limit of 3.4×10−7 M. Moreover, this detection system enabled the sensing of analytes which can enzymatically generate hydrogen peroxide. By coupling the oxidation of glucose or l-lactate catalyzed by their corresponding oxidase enzymes with terephthalic acid oxidation catalyzed by cupric oxide nanoparticles, sensitive assays of glucose and l-lactate with detection limits of 1.0×10−6 and 4.5×10−8 M were realized. The successful applications of this approach in human serum samples have also been demonstrated.