Bottom‐Up Preparation of Uniform Ultrathin Rhenium Disulfide Nanosheets for Image‐Guided Photothermal Radiotherapy

Facile preparation of multifunctional theranostic nanoplatforms with well‐controlled morphology and sizes remains an attractive in the area of nanomedicine. Here, a new kind of 2D transition metal dichalcogenide, rhenium disulfide (ReS 2 ) nanosheets, with uniform sizes, strong near‐infrared (NIR) light, and strong X‐ray attenuation, is successfully synthesized. After surface modification with poly(ethylene glycol) (PEG), the synthesized ReS 2 ‐PEG nanosheets are stable in various physiological solutions. In addition to their contrasts in photoacoustic imaging and X‐ray computed tomography imaging because of their strong NIR light and X‐ray absorptions, respectively, such ReS 2 ‐PEG nanosheets can also be tracked under nuclear imaging after chelator‐free labeling with radioisotope ions, 99m Tc 4+ . Efficient tumor accumulation of ReS 2 ‐PEG nanosheets is then observed after intravenous injection into tumor‐bearing mice under triple‐modal imaging. The combined in vivo photothermal radiotherapy is further conducted, achieving a remarkable synergistic tumor destruction effect. Finally, no obvious toxicity of ReS 2 ‐PEG nanosheets is observed from the treated mice within 30 d. This work suggests that such ultrathin ReS 2 nanosheets with well‐controlled morphology and uniform sizes may be a promising type of multifunctional theranostic agent for remotely triggered cancer combination therapy.