Fructose oxidase-like activity of CuO nanoparticles supported by phosphate for a tandem catalysis-based fructose sensor

A surge of nanozymes with oxidase-like activities is emerging in various fields, whereas nanozymes with the ability to catalyze the oxidation of saccharides have less been explored. Herein, CuO nanoparticles (NPs) with phosphate-supported fructose oxidase-like activity have been reported. Notably, reactive oxygen species (ROS) have been confirmed as the products during the process. By coupling the fructose oxidase-like activity with the peroxidase-like activity of CuO NPs, a tandem catalysis-based fructose sensor can be fabricated. In detail, CuO NPs can catalyze the fructose oxidation under O(2 )to yield ROS (e.g., H2O2, center dot OH, and O-2(center dot-)) and effectively decompose H2O2 into center dot OH. After that, terephthalic acid can be oxidized by center dot OH produced from the tandem catalysis to generate a fluorescent product. This sensor shows a linear range toward fructose (0.625-275 mu M) with a low limit of detection (0.5 mu M), which can be successfully conducted to detect fructose from real samples. Overall, this work aims to expand the catalytic types of nanozymes and provide a desirable fructose sensor.