Atomically Dispersed Dual Metal Sites Anchored Catalyst Enables Photothermally Augmented Catalytic Oxidation for Biocatalytic Tumor Therapy

Abstract

Single-atom nanozymes (SAzymes) can maximize atomic utilization efficiency and construct highly active catalytic sites for biomedical applications. Herein, atomically dispersed iron (Fe) and cobalt (Co) dual sites anchored N-doped graphene carbon (FeCoCN) catalyst is rationally constructed to achieve photothermally augmented catalytic oxidation for effective biocatalytic tumor nanotherapy. Compared with Fe SAzyme, FeCoCN SAzyme can significantly accelerate the charge transfer and improve the activity of catalytic reactions. Co-doping optimizes coordination structure and charge redistribution by facilitating the ratio of Fe²⁺ and regulating charge transfer between different metal sites and nearby coordination atoms. Bimetallic FeCoCN SAzyme possessed an ultra-high affinity for substrate H₂O₂, and the catalytic kinetic K_m value (0.589 mm) is superior to natural catalase and most reported nanozymes. The boosted catalytic activity in producing •OH is identified by density functional theory (DFT) studies. In vivo, investigation demonstrates that atomically dispersed Fe and Co dual sites anchored FeCoCN SAzyme significantly suppresses tumor proliferation under NIR laser irradiation by photothermally enhanced catalytic oxidation. Additionally, Fe- and Co-doping in FeCoCN make it suitable as a tracer for T₂ magnetic resonance imaging. This work provides a paradigm to rationally design bimetallic SAzymes with enhanced biocatalytic performance for tumor treatment.