A V2O3-ordered mesoporous carbon composite with novel peroxidase-like activity towards the glucose colorimetric assay

Abstract

It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V₂O₃-ordered mesoporous carbon composite (V₂O₃-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H₂O₂ and 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V₂O₃ nanoparticles supported by OMC, V₂O₃-OMC exhibited excellent catalytic performance with a k_cat of 1.28 × 10⁴ s⁻¹, K_M (ABTS) of 0.067 mM and K_M (H₂O₂) of 0.16 mM, and a significantly higher catalytic efficiency (k_cat/K_M) towards the oxidation of ABTS in comparison with the natural peroxidases. Furthermore, the Ping-pong BiBi mechanism was proposed to explain the catalytic reaction by V₂O₃-OMC. Based on this highly active biomimetic peroxidase and the colorimetric detection of H₂O₂, a facile analytical method was developed to detect glucose by using V₂O₃-OMC and glucose oxidase, which had a wide linear range (0.01–4 mM glucose), good selectivity and reliability for successful detection of various real samples. Thus, the novel V₂O₃-OMC peroxidase mimetic holds great promise for broad potential applications.