Shuangfei Cai

The recent progress of MXene-based nanozymes is reviewed, including the synthetic methods, enzyme-like properties, and biomedical applications.

The past four years have witnessed booming progress in single-atom nanozymes (SANs), one of the newest generations of nanozymes with atomically dispersed metal sites for catalytic biomedical uses. They show distinct advantages over their nanoparticle-based counterparts, such as well-defined electronic/geometric structures and complete atomic utilization efficiency, thus offering opportunities to develop advanced nanozymes for practical uses. The atomically dispersed active centers in SANs could also facilitate the precise regulation of catalytic performance, while probing structure–activity relationship for in-depth understanding of mechanism. In this review, we first introduce the synthetic approaches, surface engineering, and characterization techniques of SANs. Subsequently, we discuss the enzyme-like properties of SANs, including some strategies for boosting their catalytic activities. Furthermore, we present their biomedical applications, ranging from biosensors, antibacterial uses, antioxidants, to therapeutics. Finally, the challenges and opportunities of SANs are prospected.

Bacterial infections have become a serious threat to global public health. Nanomaterials have shown promise in the development of bacterial biosensing and antibiotic-free antibacterial modalities, but single-component materials are often less functional and difficult to achieve dual bacterial detection and killing. Herein, we report a novel strategy based on the effective integration of multi-modal bacterial detection and elimination, by constructing the versatile gold-silver-Prussian blue nanojujubes (GSP NJs) via a facile template etching method. Such incorporation of multi-components involves the utilization of cores of gold nanobipyramids with strong surface-enhanced Raman scattering (SERS) activity, the shells of Prussian blue as both an efficient bio-silent SERS label and an active peroxidase-mimic, and functionalization of polyvinyl pyrrolidone and vancomycin, respectively endowing them with good colloidal dispersibility and specificity against S. aureus. The GSP NJs show operational convenience in the SERS detection and excellent peroxidase-like activity for the sensitive colorimetric detection. Meanwhile, they exhibit robust near-infrared photothermal/photodynamic effects, and the photo-promoted Ag⁺ ions release, ultimately achieving a high antibacterial efficiency over 99.9% in 5 min. The NJs can also effectively eliminate complex biofilms. The work provides new insights into the design of multifunctional core-shell nanostructures for the integrated bacterial detection and therapy.