Barium tungstate nanoparticles to enhance radiation therapy against cancer.

High-Z nanoparticles have emerged as a novel type of radiosensitizers due to their relatively large X-ray cross-section and ability to enhance radical production under irradiation. Recently, CaWO4 nanoparticles have been prepared and their potential as a radiosensitizer has been demonstrated. Herein, we investigated BaWO4 nanoparticles as a novel type of alkaline-earth metal tungstate radiosensitizer for radiotherapy (RT). We synthesized BaWO4 nanoparticles using hydrothermal reaction and coated them with polyvinylpyrrolidone (PVP). We found that BaWO4 nanoparticles could more efficiently enhance hydroxyl radical production under irradiation than CaWO4 nanoparticles. When tested in vitro, BaWO4 nanoparticles showed lower toxicity than CaWO4 nanoparticles in the absence of irradiation, but induced more significant oxidative stress under irradiation. When tested in vivo, BaWO4 nanoparticles led to more efficient tumor inhibition without causing systemic toxicity. Overall, our results suggest that BaWO4 nanoparticles can efficiently enhance RT and hold great potential as a novel type of radiosensitizing agent.