Smart Cu1.75S nanocapsules with high and stable photothermal efficiency for NIR photo-triggered drug release

Thermosensitive drug delivery systems (DDSs) face major challenges, such as remote and repeatable control of in vivo temperature, although these can increase the therapeutic efficacy of drugs. To address this issue, we coated near-infrared (NIR) photothermal Cu1.75S nanocrystals with pH/thermos-sensitive polymer by in situ polymerization. The doxorubicine (DOX) loading content was up to 40 wt.%, with less than 8.2 wt.% of DOX being leaked under normal physiological conditions (pH = 7.4, 37 °C) for almost 48 h in the absence of NIR light. These nanocapsules demonstrate excellent photothermal stability by continuous longterm NIR irradiation. Based on the stable and high photothermal efficiency (55.8%), pre-loaded drugs were released as desired using 808-nm light as a trigger. Both in vitro and in vivo antitumor therapy results demonstrated that this smart nanoplatform is an effective agent for synergistic hyperthermia-based chemotherapy of cancer, demonstrating remote and noninvasive control.