Ascorbate Oxidase Mimetic Activity of Copper(II) Oxide Nanoparticles

Abstract

Although oxidase mimetic nanozymes have been widely investigated, specific biological molecules have rarely been explored as substrates, particularly in the case of ascorbate oxidase (AAO) mimetic nanozymes. Herein, we demonstrate for the first time that copper(II) oxide nanoparticles (CuO NPs) catalyze the oxidation of ascorbic acid (AA) by dissolved O2 (as a green oxidant) to form dehydroascorbic acid (DHAA), thus functioning as a new kind of AAO mimic. Under neutral conditions, the Michaelis–Menten constant of CuO NPs (0.1302 mm) is similar to that of AAO (0.0840 mm). Furthermore, the robustness of CuO NPs is greater than that of AAO, thus making them suitable for applications under various conditions. As a demonstration, a fluorescence AA sensor based on the AAO mimetic activity of CuO NPs was developed. To obtain a fluorescent product, o‐phenylenediamine (OPDA) was used to react with the DHAA produced by the oxidation of AA catalyzed by CuO NPs. The developed sensor was cost‐effective and easy to fabricate and exhibited high selectivity/sensitivity with a wide linear range (1.25×10−6 to 1.125×10−4 m) and a low detection limit (3.2×10−8 m). The results are expected to aid in expanding the applicability of oxidase mimetic nanozymes in a variety of fields such as biology, medicine, and detection science.

Facile Preparation of Homogeneous Copper Nanoclusters Exhibiting Excellent Tetraenzyme Mimetic Activities for Colorimetric Glutathione Sensing and Fluorimetric Ascorbic Acid Sensing

“…The linear regression equation was y = 195.47x + 424.57 (R 2 = 0.991), and the K m and V max values were estimated as 0.46 mM and 23.5 × 10 −4 mM s −1 , respectively. The V max was 2-fold higher than the corresponding values of the natural enzyme AAO and CuO NPs reported previously 52 (Supporting Information, Table S2), which proves the excellent AAO-like catalytic activity of Cu NCs. Based on the POD-Like Activity.…”

Atomically Dispersed Cu Nanozyme with Intensive Ascorbate Peroxidase Mimic Activity Capable of Alleviating ROS‐Mediated Oxidation Damage

“…The nonfluorescent OPDA is capable to track DHA and form 3‐(1,2‐dihydroxyethyl) furo[3,4b]‐quinoxaline (DFQ) with a strong emitting fluorescence at 425 nm. [ 47,48 ] As shown in Figure 2e, a fluorescence peak with an emission maximum at 430 nm is observed in the OPDA‐Cu SAs/CN‐AsA‐H 2 O 2 system. Furthermore, the fluorescence intensity is enhanced and linear with AsA concentration (Figure S22, Supporting Information).…”

CuO Nanozymes as Multifunctional Signal Labels for Efficiently Quenching the Photocurrent of ZnO/Au/AgSbS2 Hybrids and Initiating a Strong Fluorescent Signal in a Dual-Mode Microfluidic Sensing Platform

“…12,13 Concretely, CuO NPs could efficiently catalyze the oxidation of ascorbic acid (AA) to produce dehydroascorbic acid (DHAA) utilizing O 2 as the oxidant. 14 Inspired by this principle, a novel strategy of consuming AA by CuO nanozymes was proposed to mediate the photoelectric response for achieving the ultrasensitive detection of NSE in this paper. Meanwhile, 3-(1,2-dihydroxyethyl) furo [3,4-b]quinoxaline-1-one (DFQ) with a strong FL signal was generated via utilizing DHAA produced by CuO NPs-catalyzed oxidation of AA to react with o-phenylenediamine (OPDA), which could serve as a reliable reference for PEC analysis.…”