Core–Shell Bi2Se3@mSiO2-PEG as a Multifunctional Drug-Delivery Nanoplatform for Synergistic Thermo-Chemotherapy with Infrared Thermal Imaging of Cancer Cells

Thermo-chemotherapy combining photothermal therapy (PTT) with chemotherapy has become a potent approach for antitumor treatment. In this study, a multifunctional drug-delivery nanoplatform based on polyethylene glycol (PEG)-modified mesoporous silica-coated bismuth selenide nanoparticles (referred to as Bi 2 Se 3 @mSiO 2 -PEG NPs) is developed for synergistic PTT and chemotherapy with infrared thermal (IRT) imaging of cancer cells. The product shows no/low cytotoxicity, strong near-infrared (NIR) optical absorption, high photothermal conversion capacity, and stability. Utilizing the prominent photothermal effect, high-contrast IRT imaging and efficient photothermal killing effect on cancer cells are achieved upon NIR laser irradiation. Moreover, the successful mesoporous silica coating of the Bi 2 Se 3 @mSiO 2 -PEG NPs cannot only largely improve the stability but also endow the NPs high drug loading capacity. As a proof-of-concept model, doxorubicin (DOX) is successfully loaded into the NPs with rather high loading capacity (≈50.0%) via the nanoprecipitation method. It is found that the DOX-loaded NPs exhibit a bimodal on-demand pH- and NIR-responsive drug release property, and can realize effective intracellular drug delivery for chemotherapy. The synergistic thermo-chemotherapy results in a significantly higher antitumor efficacy than either PTT or chemotherapy alone. The work reveals the great potential of such core–shell NPs as a multifunctional drug-delivery nanosystem for thermo-chemotherapy.