TaOx decorated perfluorocarbon nanodroplets as oxygen reservoirs to overcome tumor hypoxia and enhance cancer radiotherapy.

Cancer radiotherapy (RT) is a clinically used tumor treatment strategy applicable for a wide range of solid tumors. However, during RT treatment of tumors, only a small portion of applied ionizing irradiation energy is absorbed by the tumor, in which the largely hypoxic microenvironment also limits the anti-tumor efficacy of RT. In this work, we rationally fabricate polyethylene glycol (PEG) stabilized perfluorocarbon (PFC) nano-droplets decorated with TaOx nanoparticles (TaOx@PFC-PEG) as a multifunctional RT sensitizer. The obtained TaOx@PFC-PEG nanoparticles on one hand can absorb X-ray by TaOx to concentrate radiation energy within tumor cells, on the other hand after saturating PFC with oxygen will act as an oxygen reservoir to gradually release oxygen and improve tumor oxygenation. As the result, remarkably enhanced in vivo RT treatment is achieved with TaOx@PFC-PEG nanoparticles in our mouse tumor model experiments. Our work thus presents a new nanotechnology strategy to enhance RT-induced tumor treatment by simultaneously concentrating radiation energy within tumors and improving tumor oxygenation, using one multifunctional agent.