Dual-responsive molybdenum disulfide/copper sulfide-based delivery systems for enhanced chemo-photothermal therapy

Molybdenum disulfide (MoS2)-based drug delivery systems have shown considerable potential in cancer nanomedicines. In this work, a multifunctional nanoplatform comprising MoS2 nanosheets decorated with copper sulfide (CuS) and further functionalized with polyethylene glycol (PEG) is reported. The resultant material has a particle size of approximately 115 nm, and can be loaded with doxorubicin (DOX) to a loading capacity of 162.3 mg DOX per g of carrier. Drug release is triggered by two stimuli (near infrared (NIR) irradiation and pH), and the carrier is shown to have excellent colloidal stability. The presence of both MoS2 and CuS leads to very high photothermal conversion efficiency (higher than with MoS2 alone). In vitro experiments revealed that the blank CuS-MoS2-SH-PEG carrier is biocompatible, but that the synergistic application of chemo-photothermal therapy (in the form of CuS-MoS2-SH-PEG loaded with DOX and NIR irradiation) led to greater cell death than either chemotherapy (CuS-MoS2-SH-PEG(DOX) but no NIR) or photothermal therapy (CuS-MoS2-SH-PEG with NIR). A cellular uptake study demonstrated that the nanoplatform can efficiently enter tumor cells, and that uptake is enhanced when NIR is applied. Overall, the functionalized MoS2 material developed in this work exhibits great potential as an efficient system for dual responsive drug delivery and synergistic chemo-photothermal therapy. The route employed in our work thus provides a strategy to enhance photothermal efficacy for transition metal dichalcogenide drug delivery systems.