A Versatile Platform Based on Black Phosphorus Nanosheets with Enhanced Stability for Cancer Synergistic Therapy.

Cancer can be effectively treated by photothermal therapy in combination with chemotherapy. Black phosphorus (BP) nanosheets (NSs) have been considered as a promising nanocarrier for synergistic chemo/photothermal therapy. However, the intrinsic instability of bare BP is a great challenge for drug delivery applications. Herein, we coated the BP NSs with polydopamine (PDA), and prepared a novel nanocapsule BP@PDA-PEG-FA that was modified with targeting polymer mercapto group-poly(ethylene glycol)-folic acid (HS-PEG-FA). The nanocapsule was loaded with doxorubicin (DOX) as a model drug for cervical cancer therapy. This BP-based drug delivery system exhibited enhanced stability, significantly high photothermal efficiency, and targeting ability for cancer cells. Furthermore, DOX was released from the DOX-loaded BP NSs in a tumor microenvironment at low pH under near-infrared (NIR) laser irradiation, demonstrating the effects of synergistic therapy. Both in vitro and in vivo experiments proved that the synergistic therapy combining chemotherapy with photothermal therapy had high biocompatibility, outstanding antitumor efficacy and potential clinical application.