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

Molybdenum disulfide (MoS 2 )-based drug delivery systems have shown considerable potential in cancer nanomedicines . In this work, a multifunctional nanoplatform comprising MoS 2 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 MoS 2 and CuS leads to very high photothermal conversion efficiency (higher than with MoS 2 alone). In vitro experiments revealed that the blank CuS-MoS 2 -SH-PEG carrier is biocompatible, but that the synergistic application of chemo-photothermal therapy (in the form of CuS-MoS 2 -SH-PEG loaded with DOX and NIR irradiation) led to greater cell death than either chemotherapy (CuS-MoS 2 -SH-PEG(DOX) but no NIR) or photothermal therapy (CuS-MoS 2 -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 MoS 2 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.