Single‐atom nanozymes (SAzymes) represent a new research frontier in the biomedical fields. The rational design and controllable synthesis of SAzymes with well‐defined electronic and geometric structures are essential for maximizing their enzyme‐like catalytic activity and therapeutic efficacy but remain challenging. Here, a melamine‐mediated pyrolysis activation strategy is reported for the controllable fabrication of iron‐based SAzyme containing five‐coordinated structure (FeN5), identified by transmission electron microscopy imaging and X‐ray absorption fine structure analyses. The FeN5 SAzyme exhibits superior peroxidase‐like activity owing to the optimized coordination structure, and the corresponding catalytic efficiency of Fe‐species in the FeN5 SAzyme is 7.64 and 3.45 × 105 times higher than those in traditional FeN4 SAzyme and Fe3O4 nanozyme, respectively, demonstrated by steady‐state kinetic assay. In addition, the catalytic mechanism is jointly disclosed by experimental results and density functional theory studies. The as‐synthesized FeN5 SAzyme demonstrates significantly enhanced antitumor effect in vitro and in vivo due to the excellent peroxidase‐like activity under tumor microenvironment.

A Bioinspired Five‐Coordinated Single‐Atom Iron Nanozyme for Tumor Catalytic Therapy

Engineering efficient artificial nanozyme based on chitosan grafted Fe-doped-carbon dots for bacteria biofilm eradication.

Liquid Exfoliation of V8C7 Nanodots as Peroxidase-Like Nanozymes for Photothermal-Catalytic Synergistic Antibacterial Treatment.

Nanozymes refer to nanomaterials that catalyze enzyme substrates into products under relevant physiological conditions following enzyme kinetics. Compared to natural enzymes, nanozymes possess the characteristics of higher stability, easier preparation, and lower cost. Importantly, nanozymes possess the magnetic, fluorescent, and electrical properties of nanomaterials, making them promising replacements for natural enzymes in industrial, biological, and medical fields. On account of the rapid development of nanozymes recently, their application potentials in regeneration medicine are gradually being explored. To highlight the achievements in the regeneration medicine field, this review summarizes the catalytic mechanism of four types of representative nanozymes. Then, the strategies to improve the biocompatibility of nanozymes are discussed. Importantly, this review covers the recent advances in nanozymes in tissue regeneration medicine including wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment. In addition, challenges and prospects of nanozyme researches in regeneration medicine are summarized.

Nanozymes for Regenerative Medicine

Nanozymes are promising new-generation antibacterial agents owing to their low cost, high stability, broad-spectrum activity, and minimal antimicrobial resistance. However, the inherent low catalytic activity of nanozymes tends to limit their antibacterial efficacy. Herein, a heterostructure of zinc oxide nanorod@graphdiyne nanosheets (ZnO@GDY NR) with unparallel piezocatalytic enzyme mimic activity is reported, which concurrently possesses intrinsic peroxidase-like activity and strong piezoelectric responses and effectively promotes the decomposition of hydrogen peroxide (H2O2) and generation of reactive oxygen species under ultrasound irradiation. Moreover, this piezocatalytic nanozyme exhibits almost 100% antibacterial efficacy against multidrug-resistant pathogens involving methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in vitro and in vivo. In addition, a piezoelectric activatable nanozyme-based skin patch is developed for rapid skin wound disinfections with satisfactory hemocompatibility and cytocompatibility. This work not only sheds light on the development of an innovative piezoelectric activatable nanozyme-based skin patch for rapid wound disinfection but also provides new insights on the engineering of piezocatalytic nanozymes for nanozyme antibacterial therapy.

Yunhang Liu

Papers

Ultrasmall Fe-doped carbon dots nanozymes for photoenhanced antibacterial therapy and wound healing