Nanozymes are nanomaterials with intrinsic enzyme-like properties that can overcome the current limitations of natural enzymes, such as high preparation cost, instability, restricted application scenarios, etc. Since the Fe₃O₄ nanoparticles (NPs) were shown to possess the peroxidase (POD)-like activity in 2007, thousands of nanomaterials were reported to mimic the catalytic properties of various types of enzymes including catalase (CAT), haloperoxidase, superoxide dismutase (SOD), glucose oxidase, glutathione peroxidase, hydrolase, nuclease, nitroreductase, and others. Particularly, some nanozymes showed multienzyme-like activities with regarding to the changes in application scenarios such as temperature, pH, etc. Benefiting from their distinct physical-chemical characteristics and enzyme-like catalytic properties, the nanozymes have been widely applied in various biomedical related fields from in vitro detections to in vivo therapeutic treatments. However, currently their ambiguous structure–function correlations and relatively inferior activities compared to natural enzymes promote extensive efforts for the modifications on current nanozymes and development of novel alternative nanozymes. The single-atom nanozymes (SAzymes) present a unique way to mimic the highly evolved enzyme active centers, because of their atomically dispersed catalytic sites, which leads to high atom utilization efficiency and, thus, potentially extraordinary catalytic activity. Also, the abilities to modify the active centers and/or tune the interactions between the metal centers and supporting ligands provide a precise way to engineer the SAzymes at atomic levels. Given their well-defined geometric and electronic structures, the SAzymes thus can serve as exceptional templates for deciphering the structure–function relationships, which is beneficial for further improving their catalytic performances.

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单原子纳米酶：从精确工程到广泛应用

纳米酶是一种具有内在类酶特性的纳米材料，可以克服目前天然酶的制备成本高、不稳定、应用场景受限等局限性。由于Fe ₃ O ₄纳米粒子（NPs）被证明具有过氧化物酶（ 2007 年，据报道有数千种纳米材料可以模仿各种酶的催化特性，包括过氧化氢酶 (CAT)、卤过氧化物酶、超氧化物歧化酶 (SOD)、葡萄糖氧化酶、谷胱甘肽过氧化物酶、水解酶、核酸酶、硝基还原酶和其他的。特别是，一些纳米酶在温度、pH等应用场景的变化时表现出类多酶活性。得益于其独特的物理化学特性和类酶催化特性，纳米酶已广泛应用于各种生物医学相关领域。从体外检测到体内治疗的领域。然而，目前它们模糊的结构-功能相关性和与天然酶相比相对较差的活性促进了对现有纳米酶的修饰和新型替代纳米酶的开发的广泛努力。单原子纳米酶（SAzymes）提供了一种模拟高度进化的酶活性中心的独特方法，因为它们具有原子分散的催化位点，这导致了高原子利用效率，从而具有潜在的非凡催化活性。此外，修饰活性中心和/或调节金属中心与支持配体之间相互作用的能力提供了在原子水平上改造 SAzyme 的精确方法。鉴于其明确的几何和电子结构，SAzymes因此可以作为破译结构-功能关系的特殊模板，这有利于进一步提高其催化性能。