A pH-Switchable Cerium Single-Atom Enzyme for Peri-Implantitis Therapy via JAK-STAT Signaling Axis-Mediated...

The development of high-performance, environmentally adaptive enzyme-mimicking catalysts for the treatment of peri-implantitis (PI) is of great importance yet remains highly challenging. Herein, we report a high-performance cerium single atom on B, N co-doped carbon nanotubes enzyme (SAzyme), denoted as Ce-BNC. Benefitting from its unique N/O-coordinated electronic environment and reversible Ce³⁺/Ce⁴⁺ redox cycle, Ce-BNC exhibits an intrinsic pH-switchable catalytic function, with acidic conditions favoring peroxidase (POD)-likeactivity for hydrogen peroxide (H₂O₂) activation and reactive oxygen species (ROS)-mediated antibacterial effects, whereas relatively neutral conditions promote superoxide dismutase (SOD)- and catalase (CAT)-like enzymatic cascades for ROS conversion and oxygen generation. Through this pH-switchable catalytic transition, Ce-BNC enables dynamic switching between oxidative antimicrobial activity and antioxidative microenvironment modulation. Mechanistically, this pH-switchable enzymatic relay is thermodynamically governed by reduced Gibbs free-energy barriers. This antioxidant effect further disrupts the M1 macrophage/IL-6-JAK/STAT signaling axis, thereby remodeling the inflammatory microenvironment. This work presents a microenvironment-adaptive catalytic platform with programmable bimodal activities, offering a promising paradigm for the intelligent and staged treatment of inflammatory diseases.