Nanozymes from Cu(II) Metal–Organic Gel and Melamine for Highly Active Peroxidase-Like Activity to Detect Alkaline Phosphatase

Abstract

Enzyme-like catalytic activity and efficiency of carbon-based nanomaterials are closely linked to their size, heteroatom composition, and structure, and hence the heteroatom regulation needs to be further explored. In this work, a simple and efficient strategy was proposed to develop Cu-doped 2D carbon material C 3 N 4 (Cu-C 3 N 4 -550) with excellent catalytic performance by pyrolyzing precursors of Cu(II) metal−organic gel (MOG) and melamine directly. Due to its sufficient metal active sites and adequate specific surface areas, the as-prepared Cu-C 3 N 4 -550 was endowed with excellent peroxidase-like activity to promote the oxidation of 3,3′,5,5′-tetramethylbenzidine owing to the generation of • OH in the catalytic reaction. It was amazing to find that the peroxidase mimic activity of the prepared Cu-C 3 N 4 -550 has enhanced 32.3-fold compared with bare C 3 N 4 . High peroxidase-like activity of Cu-C 3 N 4 -550 was influenced severely by the addition of antioxidant ascorbic acid (AA), alkaline phosphatase (ALP) as a typical hydrolase could catalyze substrate 2-phospho-L-ascorbic acid into AA, while AA was capable of capturing • OH generated from the catalytic reaction of Cu-C 3 N 4 -550. Hence, a sensitive, selective, and colorimetric method for the detection of ALP was established, the linear concentration of ALP in this colorimetric sensor from 0.4 to 20 U/L was acquired with a low detection limit of 0.32 U/L. This work not only provides ideas for designing enhanced peroxidase-like activity nanozymes in practical biological analysis but also broadens the MOG derivatives and carbon-based nanomaterials in colorimetric applications.

An Encyclopedic Compendium on Chemosensing Supramolecular Metal‐Organic Gels

“…Referring to Figure 3E, Song et al. introduced a novel approach for crafting a highly efficient peroxidase‐like enzyme denoted as Cu‐doped‐C 3 N 4 that involved a straightforward and effective pyrolysis process using C8 .Cu(II) metal–organic gel (MOG) and melamine as precursors [131] . The resulting Cu‐C 3 N 4 ‐550 demonstrated outstanding catalytic performance due to an ample presence of metallic active sites and appropriate surface areas.…”

Chromogenic Mechanisms of Colorimetric Sensors Based on Gold Nanoparticles

“…Noble metal-based nanomaterials have been widely used in biosensing applications, especially Au NPs. Compared with natural enzymes, Au NPs not only exhibit adjustable catalytic activity of mimetic enzymes, such as oxidases, peroxidases, superoxide dismutases (SOD) and catalases [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ], but also have advantages of high stability, easy storage conditions and low cost, making them widely used in environmental monitoring, the food industry, clinical diagnosis and therapy and other fields ( Figure 1 ) [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Specializing Carbon Nanozyme Active Sites for Sensitive Alkaline Phosphatase Activity Metal‐Free Detection

“…demonstrated a method of combining nanozymatic Fe‐doped carbon nanosheets and smartphone detection to analyze ALP activity [15g] . Moreover, nanozymes from Cu‐containing materials exhibited enhancing activity and can be utilized to establish ALP assays [15h,i] . These studies reveal that adjusting the catalytic performance of nanozymes through ALP or its related species could be a promising approach for the detection of various targets.…”