Two-dimensional non-carbonaceous materials-enabled efficient photothermal cancer therapy

Based on the unique two-dimensional (2D) planar nanostructure with atomic-thin thickness, abundant composition variations and the corresponding exceptional physiochemical/biological performances, the emerging inorganic 2D nanomaterials with high biocompatibility have been becoming one of the most promising material nanosystems of great potentials for applications in biomedicine. This review focuses on the unique photothermal-conversion property of several new representative 2D nanomaterials beyond graphene for photothermal conversion-based tumor hyperthermia and theranostic biomedicine, including transition metal dichalcogenides (TMDCs, such as MoS, WS, TiS and BiSe), black phosphorous (P), metal Pd nanosheets and their composite nanosheets. Based on high photothermal-conversion efficiency of these 2D nanomaterials, this review first highlights the design, synthesis and surface functionalization of 2D nanomaterials for photothermal therapy (PTT) ablation of cancer cells/tissues. The representative strategies of functionalizing these 2D nanomaterials for imaging-guided PTT and PTT-based synergistic cancer therapy are then discussed. The preliminary progresses on biosafety evaluation of these 2D nanomaterials were also briefly summarized and discussed. Finally, we discussed the state-of-art unsolved critical issues and challenges, and outlooked further research directions of 2D nanomaterials for potential clinical translation for PTT tumor ablation. It is believed that the fast development and promising performance of these biocompatible 2D materials can provide a highly efficient nanoplatform for combating cancer by hyperthermia.