Ultrasmall Bi@Au Schottky Heterojunction with a High Potential Barrier for Amplifying Radioimmunotherapy
Chuang Shen, Xianghong Niu, Jiaxu Zhang, Shengheng Wang, Jianwei Chen, Fei Xu, Yefan Duan, Ying Zhang, Lixing Weng, Zhimin Luo, Lianhui Wang
Abstract
Radiotherapy (RT) often has poor clinical sensitivity and tumor metastasis inhibition due to weak X-ray absorption, low energy deposition, inefficient reactive oxygen species (ROS) generation, and induction of antitumor immune response. Here, we report an ultrasmall Bi@Au Schottky heterojunction, namely, Bi@Au nanodots (Bi@Au NDs), to enhance the sensitivity of RT and activate systemic immunity for effective tumor treatment and metastasis inhibition. Bi@Au NDs exhibit a high efficiency of ROS generation and glutathione (GSH) depletion. Density functional theory calculations reveal that Bi@Au NDs with a high Schottky potential barrier can efficiently facilitate carrier separation and prevent carrier backflow, which results in abundant electrons for catalytically decomposing H 2 O 2 to • OH under X-ray irradiation. Experimental results in vitro and in vivo show that Bi@Au NDs can significantly sensitize RT by enhancing ROS generation and GSH depletion. Bi@Au ND-sensitized RT greatly induces immunogenic cell death and thus promotes a CD8 + T cell-mediated systemic immune response, ultimately inhibiting tumor metastasis. Bi@Au NDs as a kind of Schottky heterojunctions can be an effective amplifier for radioimmunotherapy.