Near‐Infrared Light‐Responsive Cu2MoS4@GelMA Hydrogel with Photothermal Therapy, Antibacterial Effect and Bone Immunomodulation for Accelerating Infection Elimination and Fracture Healing

Abstract Managing fracture infections is a significant challenge in trauma orthopedics, given the limited self‐healing capacity of fractures and the difficulty in eradicating infections. In this study, Cu 2 MoS 4 nanoparticles (CMSs) with are prepared enzyme‐like activity and both pH and near‐infrared (NIR) light responsiveness. These CMSs are combined with methacrylated gelatin (GelMA) to synthesize CMSs hydrogels (CMSs@Gel) with antimicrobial and bone tissue repair‐promoting capabilities. In vitro and in vivo experiments, the CMSs@Gel demonstrated good biocompatibility; peroxidase‐like (POD), oxidase‐like (OXD), and catalase‐like (CAT) activities; excellent photothermal conversion efficiency; and immunomodulatory capacity. Furthermore, the CMSs@Gel exhibited slow degradation, enabling it to exert different pH‐responsive enzyme activities and modulate the production of reactive oxygen species (ROS) and the polarization of macrophages throughout the treatment process. Notably, these effects are significantly enhanced under near‐infrared (NIR) light. Additionally, under NIR irradiation, the CMSs@Gel maintained the fracture environment at a mild temperature (40–42 °C), promoting osteogenesis and angiogenesis. In summary, the CMSs@Gel enhances bactericidal activity during fracture infection and effectively promotes fracture healing after infection control, providing long‐term therapeutic effects. This study offers a robust theoretical basis for the staged and long‐term treatment of fracture infections in the future.