CpG loaded MoS2 nanosheets as multifunctional agents for photothermal enhanced cancer immunotherapy

Single or few-layered MoS2 nanosheets, as a novel class of 2D nanomaterials, have received tremendous attention due to their fantastic physical and chemical properties. Here, we fabricated MoS2-PEG-CpG with a small and uniform size as a multifunctional platform for photothermal enhanced immunotherapy. MoS2 nanosheets were fabricated by chemical exfoliation and further probe sonication. To realize MoS2-based adjuvant delivery, MoS2 nanosheets were functionalized with cytosine-phosphate-guanine (CpG) and polyethylene glycol (PEG) to form MoS2-PEG-CpG nanoconjugates. As an efficient nanocarrier with excellent near infrared-light (NIR) absorbing performance, MoS2-PEG-CpG significantly promotes CpG intracellular accumulation and the effect can be further enhanced by photothermal treatment. In addition, the enhanced uptake can stimulate the production of proinflammatory cytokines and remarkably elevate the immune response level. Finally, we found that MoS2-PEG-CpG could reduce the proliferative activity of cancer cells when co-cultured with a macrophage-like cell upon NIR irradiation, implying a novel strategy for multifunctional therapeutics against cancers.