Cu -Modified Metal-Organic Framework Nanoparticles: A Peroxidase-Mimicking Nanoenzyme

The synthesis and characterization of UiO-type metal-organic framework nanoparticles (NMOFs) composed of Zr ions bridged by 2,2'-bipyridine-5,5'-dicarboxylic acid ligands and the postmodification of the NMOFs with Cu ions are described. The resulting Cu -modified NMOFs, Cu -NMOFs, exhibit peroxidase-like catalytic activities reflected by the catalyzed oxidation of Amplex-Red to the fluorescent Resorufin by H O , the catalyzed oxidation of dopamine to aminochrome by H O , and the catalyzed generation of chemiluminescence in the presence of luminol/H O . Also, the Cu -NMOFs mimic NADH peroxidase functions and catalyze the oxidation of dihydronicotinamide adenine dinucleotide, NADH, to nicotinamide adenine dinucleotide, NAD , in the presence of H O . The Cu -NMOFs-catalyzed generation of chemiluminescence in the presence of luminol/H O is used to develop a glucose sensor by monitoring the H O formed by the aerobic oxidation of glucose to gluconic acid in the presence of glucose oxidase. Furthermore, loading the Cu -NMOFs with fluorescein and activating the catalyzed generation of chemiluminescence in the presence of luminol/H O yield an efficient chemiluminescence resonance energy transfer (CRET) process to the fluorescein reflected by the activation of the fluorescence of the dye (λ = 520 nm, CRET efficiency 35%).