Black phosphorus nanosheets-based stable drug delivery system via drug-self-stabilization for combined photothermal and chemo cancer therapy

Black phosphorus (BP) nanomaterials have shown great potential as near-infrared (NIR) photothermal therapy agents and drug delivery systems for cancer therapy. However, their practical applications were still severely limited as their lack of stability under ambient conditions. Here we reported a strategy of using drug itself to stabilize BP. The active species of platinum-based anticancer drugs (DACHPt and Pt(NH₃)₂) were utilized to coordinate with BP nanosheets to form complex BP/DACHPt and BP/Pt(NH₃)₂ and improve their stability. BP nanosheets were proved to load DACHPt twice their weight and released it in acid- and NIR-responsive manner, indicating an excellent drug carrier. In vitro cytotoxicity results and apoptosis mechanism showed BP/DACHPt would almost kill all the cancer cells by combined photothermal and chemo effects. Finally in vivo results confirmed BP/DACHPt-PEG would accumulate efficiently in tumor and exert tumor ablation. Thus this novel strategy of using drug itself to stabilize BP, would not only evade the potential clinical application risks, but also construct stable BP-based drug delivery system for combined photothermal and chemo cancer therapy.