Multicomponent Transition Metal Dichalcogenide Nanosheets for Imaging-Guided Photothermal and Chemodynamic Therapy

Transition metal dichalcogenides (TMDs) have received considerable attention due to their strong absorption in the near-infrared (NIR) region, strong spin-orbit coupling, and excellent photothermal conversion efficiency (PCE). Herein, CoFeMn dichalcogenide nanosheets (CFMS NSs) are prepared via facile vulcanization of a lamellar CoFeMn-layered double hydroxide (LDH) precursor followed by polyvinyl pyrrolidone modification (to give CFMS-PVP NSs), and found to show excellent photoacoustic (PA) imaging and synergistic photothermal/chemodynamic therapy (PTT/CDT) performance. The as-prepared CFMS-PVP NSs inherit the ultrathin morphology of the CoFeMn-LDH precursor and exhibit an outstanding photothermal performance with a η of 89.0%, the highest PCE reported to date for 2D TMD materials. Moreover, 50% of maximum catalytic activity (Michaelis-Menten constant, K _m) is attained by CFMS-PVP NSs with 0.26 × 10^-3 m H₂O₂ at 318 K, markedly lower than the endogenous concentration of H₂O₂ inside tumor cells. In addition, complete apoptosis of HepG2 cancer cells and complete tumor elimination in vivo are observed after treatment with CFMS-PVP NSs at a low dose, substantiating the NSs' remarkable PTT/CDT efficacy. This work provides a new and facile approach for the synthesis of high-quality multicomponent TMD nanosheets with precise process control, the potential for mass production, and outstanding performance, providing great promise in cancer theranostics.