Peroxidase‐Mimetic and Fenton‐Like Activities of Molybdenum Oxide Quantum Dots

Abstract

Molybdenum oxide nanomaterials have become a popular nanomaterial while its catalysis behavior especially the bio‐catalysis property is little understood, even though molybdenum has been employed as a key cofactor in several important enzymes in biological system. On the basis of these, the Fenton and peroxidase‐like property of molybdenum oxide quantum dots (MoOx QDs) with mixed valence state was carefully investigated using tetramethylbenzidine (TMB) and methyl orange (MO) as the substrates. The results showed that MoOx QDs not only serve as a Fenton reagent, degrading MO to colorless products, but also exhibit intrinsic peroxidase‐mimetic activity, oxidizing TMB to the oxidized state oxTMB. The catalysis mechanism of MoOx QDs is that MoOx QDs can facilitate the decomposition of H2O2 and a large amount of radicals was generated, leading to MO decomposing and TMB oxidizing subsequently. Inspired by the findings, a visible method was developed for sensitive and selective detection of H2O2 and glucose, and the limit of detection for H2O2 and glucose is 7.75 μM and 8.95 μM (3σ/K), respectively. Moreover, glucose content in human serum samples was successfully determined by the proposed visible method, and the results are consistent well with those obtained by handheld glucose meter, suggesting a high accuracy of the present method.

Plasmon-Enhanced Peroxidase-like Activity of Nitrogen-Doped Graphdiyne Oxide Quantum Dots/Gold–Silver Nanocage Heterostructures for Antimicrobial Applications

“…Compared with natural enzymes, nanozymes possess prominent advantages of controllable activity, high stability, good durability, and low cost, which have been widely used in the fields involving biomedicine, environment, and industry. Recently, nanozyme antibacterial therapy (NABT) has been established with broad-spectrum antibacterial activity against miscellaneous bacteria and even MDR bacteria. − NABT commonly employs peroxidase-like nanozymes, which can decompose hydrogen peroxide (H 2 O 2 ) into deleterious reactive oxygen species (ROS) for bacterial elimination. Nevertheless, the low catalytic activity of nanozymes largely limits their antibacterial efficacy.…”

Functional Graphdiyne for Emerging Applications: Recent Advances and Future Challenges

“…[337,338] Nanozymes possess fascinating enzymatic catalytic properties, which show many advantages (e.g., low-cost, excellent durability, high stability, and tunable catalytic activity) over natural enzymes, and have been widely used in many fields such as biomedicine, industry, environment and so on. [339][340][341][342][343] In recent years, GDY-based nanozymes for antibacterial therapy has been regarded as an effective alternative approach with remarkably enhanced antibacterial efficacy in a broadband spectral region, [29,38,73,137,344,345] compared with traditional nanozymes (e.g., Cu 2 WS 4 NCs, [346,347] MoO x QDs, [348,349] ) due to the highly 𝜋-conjugated hexagonal pore, [12,33] good photostability, [350] tunable E g , [20] and high charge carrier mobility. [20] For example, in 2022, Zhang et al [344] reported on B-GDY that could largely simulate the production of peroxidase, and the bactericidal activity against both Gram-positive and Gram-negative bacteria was largely boosted due to the highly catalytic activity of B-GDY, in good agreement with the theoretical prediction that the doping of B atoms could provide abundant active B-defect sites and significantly lowered G in the process of H 2 O 2 decomposition.…”

Quantum Dots Compete at the Acme of MXene Family for the Optimal Catalysis

“…Over the past decade, various methods have been adopted to synthesize two-dimensional inorganic derivatives such as graphene [ 80 ], phosphorene [ 81 ], 2D layered carbides-based QDs [ 82 ], and TMOs-based QDs [ 83 ]. Due to the similar layer structures (the strong covalent or ionic bonds in layers, the weak van der Waals forces in interlayers), the synthesis of 2D MXene-derived QDs is quite similar to other inorganic QDs.…”