Dimensionality Engineering of Single-Atom Nanozyme for Efficient Peroxidase-Mimicking

Abstract

In nature, enzymatic reactions occur in well-functioning catalytic pockets, where substrates bind and react by properly arranging the catalytic sites and amino acids in a three-dimensional (3D) space. Single-atom nanozymes (SAzymes) are a new type of nanozymes with active sites similar to those of natural metalloenzymes. However, the catalytic centers in current SAzymes are two-dimensional (2D) architectures and the lack of collaborative substrate-binding features limits their catalytic activity. Herein, we report a dimensionality engineering strategy to convert conventional 2D Fe–N-4 centers into 3D structures by integrating oxidized sulfur functionalities onto the carbon plane. Our results suggest that oxidized sulfur functionalities could serve as binding sites for assisting substrate orientation and facilitating the desorption of H2O, resulting in an outstanding specific activity of up to 119.77 U mg–1, which is 6.8 times higher than that of conventional FeN4C SAzymes. This study paves the way for the rational design of highly active single-atom nanozymes.

Construction of Core–Shell MOF CSMnP with Enzyme-Like Activity for Chemotherapy and Chemodynamic Therapy

“…The OXD-like activity of CSMnP to convert O 2 to • O 2 – was investigated by the 3,3′,5,5′-tetramethylbenzidine (TMB) color reaction . The probe was able to be oxidized to oxTMB by • O 2 – with an adsorption peak at 652 nm.…”

“…The OXD-like activity of CSMnP to convert O 2 to • O 2 − was investigated by the 3,3′,5,5′-tetramethylbenzidine (TMB) color reaction. 37 The probe was able to be oxidized to oxTMB by • O 2 − with an adsorption peak at 652 nm. As shown in Figure 4d, CSMnP and Mn(III)-PBC could oxidize TMB for a color reaction, while Mn(II)-PBC could not occur in the reaction.…”

“…Generally, drugs were taken up by cells through the endocytosis-lysosome approach, so the pH value of lysosomes (pH 5.0) was adopted, 37 and the drug release behaviors of DOX@CSMnP were studied in PBS solutions with two pH values (pH 5.0 and pH 7.4). Furthermore, 37 and 42 °C were considered as the temperature of a typical normal tissue and a tumor tissue.…”

Peroxidase mimics of platinum-group metals forin vitrodiagnostics: opportunities and challenges

“…For instance, electron spin resonance (ESR) analysis was performed to probe radicals (e.g., OH and O 2 À ), 69,70 and in situ Raman measurement was conducted to track intermediates absorbing on catalytic surfaces (e.g., atomic oxygen 71 ); It is meaningful to explore new types of peroxidase mimics with superior catalytic activities and minimal usage of PGM materials. Recent studies on single-atom enzyme mimics represent a promising research direction; [72][73][74][75] PGM mimics-based diagnostic kits (e.g., lateral flow tests) may be disposed of in the environment after use. Therefore, it is crucial to assess their impact on the environment and evaluate their biosafety.…”

“…, atomic oxygen 71 ); It is meaningful to explore new types of peroxidase mimics with superior catalytic activities and minimal usage of PGM materials. Recent studies on single-atom enzyme mimics represent a promising research direction; 72–75 PGM mimics-based diagnostic kits ( e.g. , lateral flow tests) may be disposed of in the environment after use.…”