Quantum-Sized Sb@Au Schottky Heterostructure for Sensitized Radioimmunotherapy

Radiodynamic therapy (RDT) holds great potential for overcoming radioresistance and enhancing tumor immunogenicity. However, its efficacy is hindered by limited reactive oxygen species (ROS) generation due to insufficient carrier generation and transfer, which often results in tumor metastasis. Here, we report quantum-sized and narrow-bandgap Sb@Au Schottky heterostructures, namely, Sb@Au nanodots (Sb@Au NDs), to improve ROS generation for sensitizing RDT and inhibiting tumor metastasis. Experimental results and density functional theory calculations show that Sb@Au NDs give narrow bandgap and high Schottky potential barrier for promoting carrier generation and separation under X-ray irradiation, and present rich active sites for improving catalytic performance, leading to abundant ROS generation and significantly amplifying intracellular oxidative stress to enhance RDT. Sb@Au ND-sensitized RDT greatly induces immunogenic cell death and thus promotes CD8⁺ T cell-mediated systemic immunity, ultimately suppressing tumor metastasis. Our finding highlights the potential of narrow-bandgap Sb@Au NDs as an effective sensitizer for radioimmunotherapy.