▎ 摘　　要

A multifunctional theranostic nanoplatform based on nanosized graphene oxide (GO) and MnWO4 has been developed by in situ growth of MnWO4 nanoparticles onto GO surfaces in a hyperthermia polyol medium containing polyethylene glycol (PEG). In comparison with GO and MnWO4/PEG, the near infrared (NIR) absorbance of the produced GO/MnWO4/PEG nanocomposite is significantly improved, resulting in an enhanced photothermal conversion capability and a good photoacoustic (PA) imaging performance. It is worth to note that the longitudinal relaxivity r(1) of GO/MnWO4/PEG reaches impressively 11.34 mM(-1) s(-1) in a 0.5 T magnetic field, which is significantly higher than ordinary Mn(II)-based T-1 agents. In vivo magnetic resonance and PA imaging demonstrate that GO/MnWO4/PEG could serve as an efficient bimodal contrast agent to guide the cancer treatment. GO/MnWO4/PEG shows a high loading capacity for anticancer drug doxorubicin hydrochloride (DOX) by noncovalent forces, and the drug release could be triggered by lower pH value and external NIR light. Effective synergistic photothermo-chemotherapy has been performed in xenograft 4T1 tumor models after intravenous administration of GO/MnWO4/PEG/DOX. No obvious toxicity and side effect have been observed during in vivo treatment. These positive results suggest the promising application of GO/MnWO4/PEG as a versatile nanoplatform for multimodal imaging-guided cancer synergistic therapy. (C) 2018 Elsevier Ltd. All rights reserved.