Photo-thermoelectric cascade conversion drove valence state cycling of Bi2Te3@V2C heterojunction in poly(L-lactic acid) scaffold for antitumor therapy, antibacterial infection, and bone regeneration

Photo-thermoelectric-driven vanadium valence cycling enhanced ROS generation. • NIR-triggered electrical stimulation activated calcium signaling for osteogenesis. • Synergistic antitumor and antibacterial efficacy was achieved through self-enhanced chemodynamic and thermoelectric catalysis therapy. • A multifunctional scaffold achieved tumor/bacteria elimination and bone repair. The peroxidase-like activity of vanadium carbide MXene (V 2 C) nanozyme drove the valence transition from V 3+ to V 4+ , and catalyzed hydrogen peroxide to generate reactive oxygen species (ROS) for eliminating tumor and bacteria, exhibiting potential in post-resection osteosarcoma therapy. However, V 4+ could not spontaneously reduce to V 3+ , interrupting the generation of ROS. To address this, a scaffold strategy based on photo-thermoelectric driven valence cycle was proposed. Specifically, Bi 2 Te 3 @V 2 C heterojunction was constructed via electrostatic self-assembly and then incorporated into poly(L-lactic acid) scaffold using additive manufacturing technology. X-ray photoelectron spectroscopy results demonstrated that under near-infrared light irradiation, photo-thermoelectric bismuth telluride (Bi 2 Te 3 ) generated electrons via the Seebeck effect, which efficiently reduced V 4+ to V 3+ , thereby achieving vanadium ion valence cycling and enhancing ROS production. Simultaneously, the photothermal effect of Bi 2 Te 3 enhanced peroxidase-like reaction efficiency. Furthermore, Bi 2 Te 3 triggered redox reactions through thermoelectric catalysis properties, thereby elevating ROS production levels and further enhancing antitumor and antibacterial efficacy. The scaffold-generated ROS induced mitochondrial dysfunction and apoptosis in tumor cells, while also causing the leakage of bacterial intracellular substances to reduce implant-related infection risks. The experimental results showed that both its antitumor and antibacterial rates exceeded 95%. Moreover, the scaffold delivered non-invasive electrical stimulation through photo-thermoelectric conversion, which activated calcium signaling pathways to promote bone repair. This study provided a multifunctional scaffold with antitumor, antibacterial and osteogenic capabilities.