Emerging Single‐Atom Catalysts/Nanozymes for Catalytic Biomedical Applications

Abstract

Single-atom catalysts (SACs) are a type of atomically dispersed nanozymes with the highest atom utilization, which employ low-coordinated single atoms as the catalytically active sites. SACs not only inherit the merits of traditional nanozymes, but also hold high catalytic activity and superb catalytic selectivity, which ensure their tremendous application potential in environmental remediation, energy storage and conversion, chemical industry, nanomedicine, etc. Nevertheless, undesired aggregation effect of single atoms during preactivation and reaction processes is significantly enhanced owing to the high surface free energy of single atoms. In this case, appropriate substrates are requisite to prevent the aggregation event through the powerful interactions between the single atoms and the substrates, thereby stabilizing the high catalytic activity of the catalysts. In this review, the synthetic methods and characterization approaches of SACs are first described. Then the application cases of SACs in nanomedicine are summarized. Finally, the current challenges and future opportunities of the SACs in nanomedicine are outlined. It is hoped that this review may have implications for furthering the development of new SACs with improved biophysicochemical properties and broadened biomedical applications.

Engineering single-atom catalysts toward biomedical applications

“…From the view of therapeutic effects, the catalytic performances of most SACs are superior to the common nanocatalysts, facilitating the translation of SACs to preclinical applications. 398,403 For example, the photothermal conversion efficiency of Fe-SACs was ∼52.3%, outperforming the majority of the reported nanomaterials. 398,404,405 In addition, as the atomic level of SACs facilely lies at the interfaces of living systems and artificial materials, SACs are anticipated to integrate more therapeutic modalities to manage diseases than other nanomaterials.…”

Emerging materials for electrochemical CO2reduction: progress and optimization strategies of carbon-based single-atom catalysts

“…Advanced atomic-level characterization techniques and theoretical methods, such as high-resolution high-angle annular darkfield scanning transmission electron microscopy (HAADF-STEM) images, X-ray absorption spectroscopy (XAS), Raman spectroscopy and DFT calculations have been gradually applied to the characterization and study of SACs. 150,151 In this section, we focus on two techniques, HAADF-STEM and XAS.…”

Single-Atom Nanozyme Based on Mn-Center with Enhanced Peroxidase-like Activity for Organic Dye Degradation

“…Although nanozymes have many advantages, traditional nanozymes face the problem of insufficient activity, which will limit the application of nanozymes. , The synthesis of nanozymes with excellent enzyme-like activities will be a long-term challenge. Single-atom nanozymes are a new type of nanozymes that have emerged in recent years and have the advantages of high atom utilization and enzyme-like activity compared with conventional nanozymes. − Therefore, the preparation of single-atom nanozymes is an effective means to solve the low activity of traditional nanozymes. Since the emergence of single-atom nanozymes, numerous reports have been made on single-atom nanozymes.…”