BiVO4@Bi2S3 Heterojunction Nanorods with Enhanced Charge Separation Efficiency for Multimodal Imaging and Synergy Therapy of Tumor.

ABSTRACT

Despite malignant tumors being one of the most serious diseases threatening human health and living quality, exploring theranostic agents for highly effective tumor diagnosis and treatment is still full of challenges. Herein, we demonstrate the design and preparation of Tween-20-modified BiVO4@Bi2S3 heterojunction nanorods (HNRs) for multimodal computed tomography (CT)/photoacoustic (PA) imaging and radiotherapy (RT)/radiodynamic therapy (RDT)/photothermal therapy (PTT) synergistic therapy. Benefiting from the high X-ray attenuation coefficient of Bi, BiVO4@Bi2S3 HNRs exhibit a sensitive CT imaging capacity and radiation enhancement effect during RT. Meanwhile, the strong NIR absorption of Bi2S3 endows BiVO4@Bi2S3 HNRs with an excellent PA imaging and photothermal transformation capacity. More importantly, by taking advantage of the type II band alignment between BiVO4 and Bi2S3, an extra internal electric field is established to accelerate the separation of X-ray-induced electrons and holes in BiVO4@Bi2S3 HNRs, resulting in the realization of highly effective X-ray-induced RDT. Because the in vitro and in vivo experiments have verified that the RT/RDT/PTT synergistic therapeutic efficacy is greatly superior to any single treatment, it is believed that our BiVO4@Bi2S3 HNRs can be used as the multifunctional nanotheranostic platform for malignant tumor theranostics.