Hierarchical MoSe2 nanoflowers as novel nanocarriers for NIR-light-mediated synergistic photo-thermal/dynamic and chemo-therapy.

The construction of nanoplatforms that integrate multiple therapies has attracted much attention in the field of cancer treatment. Herein, selenide molybdenum (MoSe2) nanoflowers were synthesized as nanocarriers capable of delivering NIR-mediated synergetic photothermal therapy (PTT), photodynamic therapy (PDT), and drug release. All of the MoSe2 nanoflowers (150-180 nm) are made up of many thin nanosheets of about 3-4 layers of MoSe2. With the novel hierarchical nanostructure and small band gap (1.24 eV), the as-synthesized MoSe2 nanoflowers possess strong near-infrared (NIR) absorption and high photothermal conversion efficiency (61.8%). In addition, they also exhibit NIR-stimulated ˙OH generation and this is the first time that MoSe2 nanostructures have been used as a PDT agent. The mechanism was investigated, which revealed that a sufficient number of photo-excited electrons and high O2 and H+ concentrations facilitate ˙OH production. After PEGylation, MoSe2@PEG exhibits high Dox-loading capacity due to electrostatic and π-π stacking interactions. After drug loading, the resulting MoSe2@PEG-Dox system exhibits acid/photothermal-triggered drug release. The synergistic effect of chemotherapy, PTT and PDT further induces superior cancer cell apoptosis and improved antitumor effectiveness.