A reactive oxygen species amplifier based on a BiWO/BP heterojunction for high efficiency radiotherapy enhancement.

Insufficient reactive oxygen species (ROS) generation and radioresistance resulting from the intrinsic features of tumors consistently give rise to unsatisfactory therapeutic outcomes of radiotherapy (RT). Developing a multifunctional radiosensitizer capable of activating ROS-induced apoptosis and achieving multimodal therapy is highly imperative yet remains a challenge so far. Herein, a multifunctional therapeutic nanoplatform based on BiWO-BP heterojunctions for multimodal synergistic tumor treatment with glutathione depletion and amplifying ROS generation is rationally designed. Rich in high-Z elements, BiWO-BP heterojunctions are able to deposit higher radiation doses into cancer cells, enhancing the radiotherapy effect. The Z-scheme heterojunction structure facilitates the X-ray-triggered catalytic process that catalyzes intracellular overproduced HO into highly toxic ˙OH, which thus enhances ROS generation in a hypoxic environment. The unique sub-band structures of BP NSs and the synergistic effect between BiWO and BP significantly boosted O generation. Meanwhile, the acidic TME can trigger the cycle conversion of W from W to W, and the redox reaction between W and GSH consumes the high level of GSH in tumor cells and increases the production of ROS. The mild photothermal effect produced by the BiWO-BP heterojunction could further enhance the ROS generation. Both and experiments showed that the as-prepared BiWO-BP heterojunction possesses high synergistic therapeutic efficacy. This work offers a viable approach to build a multifunctional radiosensitizer with TME-triggered multiple synergistic therapies for deep tumors.