Europium-Based Coordination Polymer-Modified Vanadium Sulfide Nanocomposite with High Photothermal Conversion Efficiency as a Powerful Photothermal and Four-Mode Imaging Technique

Integrating nanomaterials with different properties into a single nanoplatform is an ingenious strategy to obtain multifunctional nanocomposites. Herein, we report an experimental strategy to encapsulate a two-dimensional structured vanadium sulfide (VS2) in a europium-based hyaluronic acid coordination polymer to obtain a high photothermal conversion efficiency nanocomposite (VS2@EuCP) while addressing the limitations of VS2 due to hydrophobicity for application under physiological conditions. The photothermal conversion efficiency of VS2@EuCP nanoparticles under 980 nm (0.5 W/cm2) laser irradiation was as high as 49.2%, and the material exhibited excellent resistance to photobleaching. The intrinsic paramagnetism, strong and broad absorbance in the near-infrared region, and downconversion fluorescence properties of VS2@EuCP materials enable VS2@EuCP to perform four-mode imaging functions, namely, conventional downconversion fluorescence imaging, magnetic resonance imaging, photoacoustic imaging, and photothermal imaging. This highly integrated functional VS2 nanocomposite structure has a promising future in the field of contrast-guided applications of photothermal materials.