Oxidase Mimic Graphdiyne for Efficient Superoxide Generation in Wide pH Ranges

Abstract

Great effort has been made in exploring techniques and catalysts for O2•− production but they always work efficiently in either acidic or base environment. Presented here is the design of a unique oxidase mimic catalyst comprising self‐assembled hemin molecules on graphdiyne (hemin/GDY) for efficient O2•− generation in wide pH ranges. Hemin molecules anchor uniformly across the carbon frame of GDY to enable atomic distribution of the active metal sites, delivering a O2•− production rate of 35.7 and 2.3 times than that of hemin and hemin/graphene, respectively. In particular, hemin/GDY can efficiently produce O2•− in acidic, alkaline, and neutral environments, delivering a wide pH behavior. Its oxidase mimic ability is demonstrated for sensing glutathione molecules in cell assays, exhibiting high selectivity, long linear range. This work opens a promising design strategy toward efficient oxidase mimic catalysts for various applications.

Insertion of Hemin into Metal–Organic Frameworks: Mimicking Natural Peroxidase Microenvironment for the Rapid Ultrasensitive Detection of Uranium

“…Upon addition of H 2 O 2 , high-spin signals and the low-spin signal diminished in intensity (Figure C), and a new peak at g = 2.01 was observed (Figure D), suggesting that both HS and LS Fe­[III] of hemin would bind with H 2 O 2 to yield an LS intermediate, resembling Compound I formation . Furthermore, in contrast to reported nanozymes, , hemin-based material , and hemin (Figure S10A), hydroxyl radicals and superoxide radicals were not detected during the catalytic process of ZIF- l -hemin (Figure S10B). Based on the results presented above, we concluded three characteristics of the catalytic mechanism for ZIF- l -hemin: (i) ping-pong reaction mechanism; (ii) iron porphyrin participates in the formation of reaction intermediates; (iii) no reactive oxygen species were generated, which were consistent with the proposed mechanism of the reaction of natural peroxidase …”

“…The “bottom-up” approach for the fabrication of such a hemin-based peroxidase mimetic catalyst allowed researchers to not only mimic catalytic function but also the active site of natural peroxidases, offering a more in-depth understanding of the genesis of the natural enzyme. Unfortunately, the requirement for structurally and chemically reproducing the active sites of natural enzymes makes the mimetic process challenging. , So far, to address this problem, various hemin-contained peroxidase mimetics have been developed. ,− But common approaches to the manufacture of these hemin-contained artificial enzymes relied on the use of biological macromolecules, such as DNA, , proteins, and polypeptides, − as the backbone to mimic the microenvironment of the natural peroxidase active center, still facing the vulnerability of biological macromolecules. Such insufficient stability has limited the wide range of applications of artificial enzymes in areas including biosensing, bioimaging, and environmental analysis.…”

Heterojunction MnO2-nanosheet-decorated Ag nanowires with enhanced oxidase-like activity for the sensitive dual-mode detection of glutathione

“…Recently, synthetic biology strategies have led to the construction and engineering of nanomaterials with oxidase-like catalytic activities (so-called nanoenzymes) that offer powerful toolkits for biomarker determination. 15,16 Compared with natural enzymes, nanozymes have advantageous properties, such as low cost, easy mass production, robustness, and tunable catalytic activity. Hence, they are suitable alternatives for detecting GSH concentrations utilizing a colorimetry method.…”

A two-dimensional thin Co-MOF nanosheet as a nanozyme with high oxidase-like activity for GSH detection

“…This increase in activity probably resulted from the quenching of the photo-generated holes, which would inhibit the recombination of electrons and holes and thus promote the catalytic activity of the oxidase-like nanozyme. 35 The above results clearly indicate that ˙OH and O 2 ˙ − were the main intermediates formed during the catalytic process of the oxidase mimic.…”