Dual-atom nanozymes: Synthesis, characterization, catalytic mechanism and biomedical applications.

Dual-atom nanozymes (DAzymes), a novel class of nanozymes featuring dual-metal atomic active centers, mimic the multi-metal synergistic mechanisms of natural enzymes to achieve superior catalytic activity compared to conventional single-atom nanozymes. Their unique dual-atom architecture not only effectively mitigates metal atom aggregation but also significantly enhances substrate adsorption capacity and catalytic efficiency through interatomic electronic coupling and spatial synergy. This structural innovation addresses critical limitations of single-atom nanozymes, including low metal loading and homogeneous active sites. This review systematically summarizes recent advancements in DAzymes: First, we elucidate their design principles and structural advantages, with a focus on precise synthesis strategies (e.g., spatial confinement, coordination stabilization) and atomic-level characterization techniques (e.g., synchrotron radiation-based X-ray absorption spectroscopy, spherical aberration-corrected electron microscopy). By unraveling structure-activity relationships, we clarify the multi-dimensional regulatory mechanisms of dual-atom systems-including coordination environments, electronic coupling, and spatial configurations-on redox enzyme-like activities such as peroxidase and superoxide dismutase mimics. Furthermore, we elaborate on their groundbreaking biomedical applications, including antibacterial and antitumor therapies via reactive oxygen species (ROS) regulation, antioxidant damage repair, and biosensing. This review aims to provide theoretical guidance for the rational design of high-performance DAzymes and to advance their translational applications in precision medicine and intelligent biomaterials.