cis-Platinum pro-drug-attached CuFeS2 nanoplates for in vivo photothermal/photoacoustic imaging and chemotherapy/photothermal therapy of cancer.

Photothermal therapy (PTT) has attracted considerable attention in cancer treatment. Herein, the facile synthesis of copper iron sulfide (chalcopyrite, CuFeS2) nanoplates (NPs) with well-defined shape was achieved by a template-mediated method. Chitosan (CS), a linear cationic polysaccharide, was used to improve the physiological stability and biocompatibility. CuFeS2 NPs with strong near-infrared (NIR) absorbance enabled contrasts in photothermal and photoacoustic (PA) imaging. In vitro and in vivo tumor ablation studies further demonstrated that CS-functionalized CuFeS2 (CuFeS2-CS) NPs could convert 808 nm NIR light into heat for PTT with a photothermal conversion efficiency up to 30.5%, which was clearly higher than that of CuS NPs (only 21.4%). Furthermore, CuFeS2-CS NPs could also load cis-platinum pro-drug (CuFeS2-CS-Pt), and CuFeS2-CS-Pt showed a better synergistic therapeutic effect with respect to either chemotherapy or PTT.