Formation of porous Cu hydroxy double salt nanoflowers derived from metal–organic frameworks with efficient peroxidase-like activity for label-free detection of glucose

Abstract

Currently, nanomaterials with peroxidase activity have become an important colorimetric tool for biomolecular detection. However, compared with natural enzymes, the efficiency of most nanozymes is still lower. Here, with a leaf-like metal-organic-framework-5 as both a precursor and a template and copper acetate as a second precursor, hierarchical Cu hydroxy double salt (HDS) nanoflowers have been prepared and used as a label-free glucose colorimetric detection platform. We have demonstrated a scalable and facile synthesis of hierarchical Cu HDS nanoflowers, and density functional theory (DFT) calculations confirmed that there exists a hydrogen bond between the terephthalate anions and the layer OH group. The composition of Cu hydroxyl double salt is [Cu4(OH)6][BDC]·2H2O. Importantly, for the first time, the as-prepared Cu HDSs were demonstrated as peroxidase mimics to catalyze the oxidation of the enzyme substrate, 3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, which accompanies a color change from colorless to blue and followed classic Michaelis-Menten models. Based on these findings, a colorimetric method based on Cu HDSs that is highly sensitive and selective for the detection of glucose was developed, with a low detection limit of 0.5 μM. The clinical applicability of the sensor is also proven to be suitable for sensing glucose in blood, suggesting that Cu HDSs could be used in the construction of portable sensors for point-of-care diagnosis and on-site tests.

Facile synthesis of Cu/Ls MOF for laccase-like oxidative decomposition of phenols and identification of toxicity effects for C. elegans

“…Figure 2 showed the FT-IR spectra of Ls and Cu/Ls MOF. The spectrum of the Ls featured a characteristic peak at 1616 cm − 1 , due to the asymmetric stretching vibration of the carboxylate moiety, along with symmetric stretching vibrations at 1402 cm − 1 (Li et al, 2018). The splitting of the broad C = O asymmetric stretching vibration band at peaks 1616 cm − 1 re ected the formation of Cu-O coordination (1598 and 1660 cm − 1 ) (Liang et al, 2017;Shams et al, 2019).…”

Peroxidase catalytic activity of carbon nanoparticles for glutathione detection

“…Compared with peroxidases and other nanoparticles, CNPs are low-cost, easily accessible, and stable. 32,33 Structural analyses of CNPs revealed that they possessed a nanocrystalline core of graphitic sp 2 carbon atoms, functionalized with peripheral hydroxy and carboxylic/carbonyl moieties. 34 Functionalization of graphene surfaces with carboxylic groups is vital for the reduction of H 2 O 2 according to density functional theory.…”

Green Synthesis of Fluorescent Carbon Quantum Dots from Azadirachta indica Leaves and Their Peroxidase-Mimetic Activity for the Detection of H2O2 and Ascorbic Acid in Common Fresh Fruits

“…Afterward, a variety of nanomaterials including metal oxides (ZnFe 2 O 4 , V 2 O 5 ), metal sulfides (MoS 2 , CuS), noble metals (Au, Ag, Pd), quaternary CuZnFeS nanocrystals, graphene oxide, metal–organic framework (MOFs), , iron doped CuSn­(OH) 6 microspheres, ternary polyaniline–MnO 2 –Pd nanowires, and nitrogen-doped carbon nanomaterials were discovered that had peroxidase-like activity in association with H 2 O 2 . The important characteristics of these enzyme-mimetic nanomaterials were found to detect H 2 O 2 , glucose, immunoassay, glutathione, and cancer cell detection . However, one of the major limitations of these nanomaterials is their synthesis from doping of chemical materials and the use of expensive and toxic chemicals; this, along with multistep synthesis, made it a tedious process which limits the application of these nanomaterials .…”