A groundbreaking study led by researchers at Huazhong University of Science and Technology (HUST) has developed a high-performance near-infrared (NIR) computational spectrometer using finely-tuned lead sulfide (PbS) quantum dots (QDs). This innovation, published in Nano Research, achieves a spectral resolution of 1.5 nm, making it a powerful tool for applications ranging from qualitative material identification to quantitative alcohol content measurement in liquor. The study highlights the critical role of QD monodispersity and precise synthesis in enhancing spectrometer performance, paving the way for portable, low-cost NIR spectrometers in industrial and consumer applications.

Single-atom cobalt catalysts have been recognized as promising alternatives to natural enzymes. However, their relatively low catalytic activity greatly limits their further application. Herein, Single cobalt sites immobilized on defective carbon nanosheets (2D Co-CN(H)) can act as efficient oxidase mimics with high atom utilization efficiency. In particular, the 2D Co-CN(H) catalysts are found to be twice as effective as defect-free Co-CN catalysts. Combined experimental and theoretical analyses reveal that the defects around atomic cobalt sites can rationally regulate the electronic distribution, significantly promoting the cleavage of O-O bonds and thus improving their oxidase-like performance. Taking advantage of the excellent oxidase-like activity of 2D Co-CN(H) catalysts and the good photothermal properties of oxTMB, an innovative dual-mode colorimetric-photothermal sensing platform toward effective discrimination and detection of dihydroxybenzene isomers has been successfully constructed. This study not only highlights the important role of defects on the oxidase-like activity of single-atom nanozymes, but also broadens their potential applications in environmental conservation.

Natural enzymes are highly efficient catalysts with strong substrate specificity, making them ideal for biomedical applications. However, they often face issues such as variability, high costs, challenging preparation processes, and difficulties in large-scale production. This has led to significant efforts in developing effective nanoenzymes and exploring their application potential. In recent years, carbon dots (CDs) have gained attention due to their strong fluorescence, excellent biocompatibility, and low cytotoxicity. Cationic CDs, which possess a positively charged surface, have shown the ability to mimic natural enzyme applications. The positive charge on the surfaces of these nanomaterials significantly influences their fluorescence, biological activity, and interactions with other biomolecules. Therefore, understanding how surface charge affects the performance of CDs is crucial for enhancing their usability. Considerable progress has been made in the design, synthesis, and mechanistic research of enzyme-like cationic CDs, as well as their advanced applications. This article reviews the latest research on the design structure, catalytic mechanisms, biosensing capabilities, and biomedical applications of enzyme-like cationic CDs. First, we review the synthesis strategies for cationic CDs and how surface charge influences their physical and chemical properties. Next, we highlight various applications of these cationic CDs, demonstrating their use in areas such as detection, biomedical applications (including antibacterial agents, gene carriers, and therapeutic agents), catalysis, and more. Finally, we discuss the challenges and obstacles faced in the development of cationic CDs and look forward to exploring new applications in the future.