Enhanced peroxidase-like activity of CuWO4 nanoparticles for the detection of NADH and hydrogen peroxide

Herein, we demonstrate for the first time the peroxidase mimicking properties of CuWO4 nanoparticles (CuWO4 NPs) and a simple colorimetric method for the determination of nicotinamide adenine dinucleotide (NADH) based on the inhibition of peroxidase-like properties of CuWO4 NPs. A one-pot hydrothermal process was used to synthesize the CuWO4 NPs and XRD, SEM, HR-TEM and XPS were used to confirm the formation of CuWO4 NPs. The synthesized CuWO4 NPs could catalyze the oxidation of typical peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce a visible blue color reaction with absorption maxima centered at 652 nm. The CuWO4 NPs exhibit superior kinetics over the natural enzyme horse radish peroxidase (HRP) with lower Km value. The CuWO4 NPs peroxidase mimicking system was optimized for NADH sensing in the concentration range of 0.2-380 mu M (R-2 = 0.98) with a detection limit of 0.2 mu M. Moreover, the CuWO4 NPs modified glassy carbon electrode (GCE) reduced H2O2 at a lower onsite potential (-200 mV) thereby, allowing us to electrochemically sense hydrogen peroxide with a linear range of 24.87 mu M-3.6 mM (R-2 = 0.99) and a sensitivity of 207.64 mu A mM(-1). (C) 2017 Elsevier B.V. All rights reserved.