Oxidase mimicking of CuMnO2 nanoflowers and the application in colorimetric detection of ascorbic acid

Synthesis of MnO2 sub-microspheres with effective oxidase-mimicking nanozymes for the colorimetric assay of ascorbic acid in orange fruits and juice

“…This change was primarily brought about by the enediol group of AA reducing ox-TMB. 54,55 When the solution was saturated with N 2 gas, the absorbance decreased (Fig. 3b), indicating the presence of oxidase activity.…”

“…In comparison with the blank, using tert-butyl alcohol shows no obvious decrease in the absorbance intensity, indicating very little OH generation, whereas p-benzoquinone and NaN 3 had a certain inhibitory effect on the catalytic activity, indicating that O 2 À and 1 O 2 are produced in this catalytic process. 54,56,57 Eqn ( 2)-( 4) represent a plausible catalytic mechanism. The electrons transfer from Mn 2+ ions to dissolved oxygen (O 2 ) to generate O 2…”

Calcium Fluoride/Manganese Dioxide Nanocomposite with Dual Enzyme-like Activities for Uric Acid Sensing: A Comparative Study of Enzyme and Nonenzyme Methods

“…The high-resolution Mn 2p XPS spectrum was deconvoluted into three peaks centered at 642.1, 654.0, and 643.2 eV corresponding to Mn 2+ , Mn 3+ , and Mn 4+ , respectively (Figure 2d). 32 The high-resolution O 1s XPS spectrum shown in Figure 2e was divided into two peaks at 529.9 eV (lattice oxygen) and 531.8 eV (surface-adsorbed water). 26 FTIR spectroscopy was employed to analyze the molecular structure and chemical composition of CM Nc (Figure 2f).…”

Light-Mediated Modulation of Enzyme-Mimetic Activity of CuMnO2 Nanosheets

“…7−10 Since we first reported the intrinsic pH-switchable enzyme-mimetic activities (peroxidase-, oxidase-, and catalase-like) of CuMnO 2 nanoflakes (CuMnO 2 NFs), 11 CuMnO 2 NFs have garnered more attention and been rapidly applied in various biochemical fields for their enzyme-like performance, such as in toxic pollutant removal, 12 bacterial elimination, 7 and colorimetric detection of ascorbic acid. 13 To the best of our knowledge, one of the major challenges and the high-profile question of the current approach for nanozymes is designing superior catalytic activity over naturally occurring enzymes. 14−16 So far, it has been demonstrated that nanozymes' catalytic activity can be tailored via constructing atomic structures, surface modification, size-morphology modulation, external trigger employment, etc.…”

“…Among numerous delafossite materials, the most commonly known copper-based-manganese delafossite CuMnO 2 is widely applied in optoelectronic devices, , self-powered photodetectors, photo and gas sensing, photoelectrochemical detection, , and photocatalysis , on account of the gap which is close to the optimal value required for terrestrial applications. Aside from the superior optical properties, the good biocompatibility, existence of core elements of natural enzymes, highly efficient Fenton-like catalysis capacity, and low cost of CuMnO 2 also render great potential in biochemical fields. − Since we first reported the intrinsic pH-switchable enzyme-mimetic activities (peroxidase-, oxidase-, and catalase-like) of CuMnO 2 nanoflakes (CuMnO 2 NFs), CuMnO 2 NFs have garnered more attention and been rapidly applied in various biochemical fields for their enzyme-like performance, such as in toxic pollutant removal, bacterial elimination, and colorimetric detection of ascorbic acid …”