Ferrous Selenide Stabilized Black Phosphorus Heterojunction Sonosensitizer for MR Imaging-Guided Sonodynamic Therapy of Bladder Cancer.

It is urgent to develop an alternative dynamic therapy-based method to overcome the limited efficacy of traditional therapy methods for bladder cancer and the damage caused to patients. Sonodynamic therapy (SDT) has the advantages of high tissue penetration, high spatiotemporal selectivity, and being non-invasive, representing an emerging method for eradicating deep solid tumors. However, the effectiveness of SDT is often hindered by the inefficient production of reactive oxygen species and the nondegradability of the sonosensitizer. To improve the anti-tumor effect of SDT on bladder cancer, herein, a BP-based heterojunction sonosensitizer (BFeSe₂) was synthesized by anchoring FeSe₂ onto BP via P-Se bonding to enhance the stability and the effect of SDT. As a result, BFeSe₂ showed great cytotoxicity to bladder cancer cells under ultrasound (US) irradiation. BFeSe₂ led to a notable inhibition effect on tumor growth in subcutaneous tumor models and orthotopic tumor models under US irradiation. In addition, BFeSe₂ could also enhance T2-weighted magnetic resonance imaging (MRI) to achieve monitoring and guide treatment of bladder cancer. In general, BFeSe₂ sonosensitizer integrates MRI functions for precise treatment, promising great clinical potential for the theranostics of bladder cancer.