Stable black phosphorus/Bi2O3 heterostructures for synergistic cancer radiotherapy

X-ray induced photodynamic therapy (X-ray-PDT) is a promising approach for synergistic cancer radiotherapy and development of suitable radiosensitizers is highly desired. In this paper, we propose black phosphorus/Bi 2 O 3 (BP/Bi 2 O 3 ) heterostructures as efficient and biocompatible radiosensitizers for synergistic cancer radiotherapy. The heterostructures are synthesized by growth of ultrasmall Bi 2 O 3 nanoparticles onto BP nanosheets . The Bi 2 O 3 decoration inhibits the rapid degradation of BP nanosheets by occupation of the defect sites , and the synergistic effects of BP and Bi 2 O 3 enable 1 O 2 overproduction under X-ray irradiation. This X-ray-PDT effect of the BP/Bi 2 O 3 nanosheets enhances the radiotherapy activity towards cancer cells by inducing cell apoptosis and cycle arrest. In vivo treatment of melanoma conducted on a clinical radiotherapeutic instrument demonstrates that the BP/Bi 2 O 3 sensitized radiotherapy inhibits tumor growth efficiently. Furthermore, the BP/Bi 2 O 3 nanosheets composed of biological friendly P, O, and Bi elements shows good biocompatibility in vitro and in vivo . This radiosensitizer thus has immense clinical potential for cancer therapy, and our findings reveal a general strategy to fabricate stable BP-based heterostructures for different applications.