Cu_0.89Zn_0.11O as a Peroxidase-Mimicking Nanozyme with High Sensitivity for Glucose and Antioxidant Detection

Nanomaterial-based enzyme mimetics (nanozymes) is an emerging field of research that promises to produce alternatives to natural enzymes for a variety of applications.¹The search for the most cost-effective and efficient inorganic nanomaterials, such as metal oxides, cannot be won by pristine CuO.² However, unlike CuO, the Zn-doped CuO (Zn-CuO) nanoparticles reported in this paper reveal superior peroxidase-like enzyme activity. This places Zn-CuO in a good position to participate in a range of activities aimed at developing diverse enzyme applications.³ The peroxidase-like activity was tested and confirmed against various chromogenic substrates in the presence of H₂O₂ and obeyed the Michaelis–Menten enzymatic pathway. The mechanism of enhanced enzymatic activity was proved by employing terephthalic acid as a fluorescence probe and by electron spin resonance. The nanozyme, when tested for the detection of glucose, showed a substantial enhancement in the detection selectivity. The limit of detection (LOD) was also decreased reaching a limit as low as 0.27 ppm. Such a low LOD has not been reported so far for the metal oxides without any surface modifications. Moreover, the nanozyme (Zn-CuO) was utilized to detect the three antioxidants tannic acid, tartaric acid, and ascorbic acid and the relative strength of their antioxidant capacity was compared.

References:

1. H. Wei and E. Wang, Chem. Soc. Rev., 2013, 42, 6060-6093.

2. W. Chen, J. Chen, A. L. Liu, L. M. Wang, G. W. Li and X. H. Lin, ChemCatChem., 2011, 3, 1151 – 1154.

3. K. M. Koeller, C. H. Wong, Nature 2001, 409, 232-240.