Transformation of Black Phosphorus through Lattice Reconstruction for NIR‐II‐Responsive Cancer Therapy

Abstract The photothermal performance of black phosphorus (BP) in the near infrared (NIR)‐II bio‐window (1000–1500 nm) is low, which limits its biomedical applications. Herein, ultrasmall nickel phosphide quantum dots (Ni 2 P QDs) are synthesized with BP quantum dots (BPQDs) as the template by topochemical transformation. The size of Ni 2 P QDs is ≈3.5 nm, similar to that of BPQDs, whereas the absorption and photothermal conversion efficiency of Ni 2 P QDs at 1064 nm (43.5%) are significantly improved compared with those of BPQDs. To facilitate in vivo applications, an Ni 2 P QDs‐based liposomal nano‐platform (Ni 2 P‐DOX@Lipo‐cRGD) is designed by incorporation of Ni 2 P QDs and doxorubicin (DOX) into liposomal bilayers and the interior, respectively. The encapsulated DOX is responsively released from liposomes upon 1064‐nm laser irradiation owing to the photothermal effect of Ni 2 P QDs, and the drug release rate and amount are controlled by the light intensity and exposure time. In vivo, experiments show that Ni 2 P‐DOX@Lipo‐cRGD has excellent tumor target capability and biocompatibility, as well as complete tumor ablation through the combination of photothermal therapy and chemotherapy. The work provides a new paradigm for the NIR‐II transformation of nano‐materials and may shed light on the construction of multifunctional nano‐platforms for cancer treatment.