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

Abstract

Nanozymes are artificial enzymes, which can substitute traditional biological enzymes for multifield applications. However, to date, it remains challenging to search novel mimic enzymes or multienzyme mimics. Herein, a facile and green method for preparing monodisperse, homogeneous copper nanoclusters (Cu NCs) with smaller size was developed, which used cysteamine as a template and hydrazine hydrate as a reductant to reduce Cu 2+ . The as-prepared Cu NCs exhibited excellent tetraenzyme-like activities, including peroxidase (POD)-, catalase (CAT)-, superoxide dismutase (SOD)-, and ascorbic acid oxidase (AAO)-mimic activities. The mechanisms, kinetics, and catalytic performances of Cu NCs were systematically studied. Moreover, based on the POD-like activity of Cu NCs, sensitive and simple colorimetric sensing glutathione (GSH) was explored, with the low limit of detection of 0.89 μM GSH (S/N = 3). Additionally, a novel fluorimetric ascorbic acid (AA) sensor was developed with the linear range of 0.5−30 μM and limit of detection (LOD) of 0.144 μM, on the basis of the principle that AA is oxidized to dehydroascorbic acid (DHAA) specifically catalyzed by the AAO-like activity of Cu NCs, while DHAA can further react with ophenylenediamine (OPDA) to generate a highly fluorescent quinoxaline (DFQ) derivative. The as-proposed colorimetric GSH sensor and the fluorimetric AA sensor were capable of detecting GSH and AA, respectively, in real samples accurately and reproducibly. Thus, the Cu NCs-based multienzyme mimic is a promising candidate for biocatalysis and biosensing.

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).…”

Triple-enzyme mimetic activity of Fe3O4@C@MnO2 composites derived from metal–organic frameworks and their application to colorimetric biosensing of dopamine

“…Nanomaterials with high multi-enzyme activities tend to have greater advantages and application prospects in many fields. However, only a few nanomaterials have been reported to display multi-enzyme activities, like Co 3 O 4 [14], NiPd hollow NPs [15], MFe 2 O 4 (M = Mg, Ni, Cu) [16], V 6 O 13 [17], CoMo hybrids [18], Co 2 V 2 O 7 [19], Cu 3 V 2 O 7 (OH) 2 nanoribbons [20], CdCo 2 O 4 nanosheets [21], CDs@Cu 4 O 3 nanocomposites [22], Bi@PVP@AuPt nanoparticles [23], Fe 3 C decorated carbon nanofibers [24], and copper nanoclusters (Cu NCs) [25]. However, these reported multi-enzyme-like nanozymes are weakly magnetic or nonmagnetic, and most of them are metal oxides composed of noble metals with high cost, which may lead to difficult separation and easy agglomeration of the nanozymes in their application.…”

A Fluorescent Probe Based on Polyethyleneimine Protected Copper Nanoclusters for the Assay of Tetracycline Hydrochloride and Vitamin B12

“…[29] At present, the CuNCs as a kind of chemical sensor has attracted significant attention for the sensing of nitrite ion, [30] iodine, [31] Hg 2 + , [32] Fe 3 + , [33] Al 3 + and pyridoxal 5'-phosphate, [34] trypsin, [27] H 2 O 2 , [29] glucose, [35] MicroRNAs, [36] actin, [37] heparin, [38] β-galactosidase, [39] methyl mercaptan, [40] glutathione and ascorbic acid. [41] However, it is a huge challenge to prepare CuNCs with good stability and high QYs by sample and facile methods. [38,42] Currently, several facile methods have focused on the synthesis and application of CuNCs.…”