Boosting the Radiosensitizing and Photothermal Performance of Cu2–xSe Nanocrystals for Synergetic Radiophotothermal Therapy of Orthotopic Breast Cancer

The small difference between tumor and normal tissues in their responses to ionizing radiation has been a significant issue for radiotherapy of tumors. Herein, we report that dumbbell-shaped heterogeneous copper selenide-gold nanocrystals can serve as an efficient radiosensitizer for enhanced radiotherapy. The mean lethal dose of X-rays to 4T1 tumor cells can be drastically decreased about 40%, i.e., decreasing from 1.81 Gy to 1.10 Gy after culture with heterostructures. Due to the synergetic effect of heterostructures, the dose of X-rays is also much lower than those obtained from mixture of Cu2-xSe + Au nanoparticles (1.78 Gy), Cu2-xSe nanoparticles (1.72 Gy) and Au nanoparticles (1.50 Gy), respectively. We demonstrate that the sensitivity enhancement ratio of Cu2-xSe nanoparticles was significantly improved 45% (i.e., from 1.1 to 1.6) after the formation of heterostructures with gold. We also show that the hetero-nanocrystals exhibit an enhanced photothermal conversion efficiency, due to the synergetic ...