BSA-exfoliated WSe ₂ 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 WSe₂ for combined photothermal and photodynamic cancer therapy. WSe₂ 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 WSe₂-BSA nanosheets obtained with high stability in physiological solutions and good biocompatibility without further functionalization. The WSe₂-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 WSe₂ nanosheets with NIR irradiation. The therapeutic efficacy of the MB-loaded WSe₂-BSA (WSe₂-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 WSe₂ nanosheets could be a promising therapeutic agent and smart carrier for the synergistic combination of phototherapy towards biomedical applications.