Antimony-Doped Tin Oxide Nanocrystals for Enhanced Photothermal Theragnosis Therapy of Cancers

The doped semiconductor nanocrystal with free holes in valence band exhibits strong near-infrared (NIR) local surface plasmon resonance effects, which is essential for photothermal agents. Herein, the hydrophilic Sb doped SnO₂ nanocrystals were successfully prepared by a simple hydrothermal synthesis method. The doping makes the Sb doped SnO₂ nanocrystals possessing defect structures. Compared with the un-doped SnO₂ nanocrystals, Sb doped SnO₂ nanocrystals exhibit stronger absorption in the NIR region from 500 to 1,100 nm and higher photothermal conversion efficiency (up to 73.6%) which makes the synthesized Sb doped SnO₂ nanocrystals be used as excellent photothermal agents. Importantly, Sb doped SnO₂ nanocrystals can efficiently kill cancer cells both in vitro and in vivo under the irradiation of a 980 nm laser with a power density of 0.6 W cm^–2. In addition, Sb doped SnO₂ nanocrystals can also be served as efficient CT imaging agents owing to the large X-ray attenuation coefficient of tin.