BSA-exfoliated WSe nanosheets as a photoregulated carrier for synergistic photodynamic/photothermal therapy.

In this study, we present the synthesis and application of a new therapeutic platform based on photosensitizer-loaded, two-dimensional layered nanomaterials of WSe for combined photothermal and photodynamic cancer therapy. WSe nanosheets are synthesized by a simple and efficient chemical exfoliation using bovine serum albumin (BSA) as an effective exfoliating agent and strong stabilizing agent, endowing the WSe-BSA nanosheets obtained with high stability in physiological solutions and good biocompatibility without further functionalization. The WSe-BSA nanosheets can be employed not only as an efficient photothermal agent but also as a carrier to load methylene blue (MB) as a photosensitizing agent for photodynamic therapy. Moreover, the generation of singlet oxygen can be regulated by controlling the release of MB from the WSe nanosheets with NIR irradiation. The therapeutic efficacy of the MB-loaded WSe-BSA (WSe-BSA/MB) complexes was evaluated in vitro and in vivo. It was found that dual-mode photothermal and photodynamic therapy has a significant synergistic effect and dramatically improves the therapeutic efficacy toward cancer cells compared with single mode treatment. These findings indicate that WSe nanosheets could be a promising therapeutic agent and smart carrier for the synergistic combination of phototherapy towards biomedical applications.