Radiotherapy is usually accompanied by side effects to healthy tissue and radiation resistance of tumor cells in clinical application. Therefore, how to enhance radiation effect and reduce radiation resistance is the key problem to enhance radiotherapy efficacy. In recent years, the development of nanomaterials with radiation catalysis function has provided us with opportunities. Here, we report a radiocatalytic platform using inorganic semiconductor nanoheterojunctions WO₃@Ag₂WO₄@ chitosan (WO₃@Ag₂WO₄@CS) as radiation sensitizers to improve the radiotherapeutic effect of tumors by enhancing radiosensitization and reducing radioresistance. On one hand, WO₃@Ag₂WO₄@CS with a higher atomic number has better X-ray absorptivity and can deposit a large amount of radiation dose upon X-ray irradiation. In addition, due to the heterojunction structure, a large number of electron-hole pairs can be generated and separated under X-ray trigger. The WO₃@Ag₂WO₄@CS nanoheterojunctions thus can effectively decompose the surrounding hydrogen peroxide/water into free radicals to kill cancer cells by electron-hole pairs. On the other hand, WO₃@Ag₂WO₄@CS nanoheterojunctions also have the ability to consume intracellular GSH through redox reaction, leading to increased ROS level and reduced radioresistance. Our study provides a novel nanoradiosensitizer that can improve the radiotherapeutic efficacy by enhancing the radiation response and reducing radioresistance of tumors.

在临床应用中，放射疗法通常伴随着对健康组织的副作用和肿瘤细胞的放射抗性。因此，如何提高放疗效果，降低放疗抵抗力是提高放疗疗效的关键问题。近年来，具有辐射催化功能的纳米材料的发展为我们提供了机遇。在这里，我们报告了使用无机半导体纳米异质结WO ₃ @Ag ₂ WO ₄ @壳聚糖（WO ₃ @Ag ₂ WO ₄ @CS）作为放射增敏剂的放射催化平台，可通过增强放射增敏作用和降低放射抵抗力来改善肿瘤的放射治疗效果。一方面，WO ₃原子序数更高的Ag ₂ WO ₄ CS具有更好的X射线吸收率，并且在X射线辐照时会沉积大量的辐射剂量。另外，由于异质结结构，在X射线触发下可以产生并分离大量的电子-空穴对。因此，WO ₃ @Ag ₂ WO ₄ @CS纳米异质结可以有效地将周围的过氧化氢/水分解为自由基，从而通过电子-空穴对杀死癌细胞。另一方面，WO ₃ @Ag ₂ WO ₄@CS纳米异质结也具有通过氧化还原反应消耗细胞内GSH的能力，从而导致ROS水平升高和放射抗性降低。我们的研究提供了一种新型的纳米放射增敏剂，可以通过增强放射反应和降低肿瘤的放射抵抗力来提高放射治疗功效。