Stable black phosphorus nanosheets exhibiting high tumor-accumulating and mitochondria-targeting for efficient photothermal therapy via double functionalization

Black phosphorus (BP) exhibited excellent biocompatibility and high photothermal conversion efficiency near infrared light, which makes it very promising for photothermal therapy. However, practical applications are highly hampered by its no targeting property and rapid degradation in cancer cells, especially in the strong intracellular oxidative stress. Here, we reported that the mitochondrial targeting peptide functionalized black phosphorus nanosheets covered with an acid-labile polymer shell (doubly functionalized black phosphorus nanosheets, DFBP) exhibited good stability. Doubly functionalized black phosphorus nanosheets not only have excellent ability of accumulating in tumor tissue via surface charge switching, but also can target mitochondria. The doubly functionalized black phosphorus nanosheets resulted in robust cancer cell uptake but very poor normal cell accumulation. In vivo, the black phosphorus nanosheets could highly accumulate in tumor and specifically target mitochondria, generating en...