Metallo-Dye-Based Supramolecular Nanoassembly for NIR-II Cancer Theranostics.

Retaining intrinsic photophysical performance and efficient therapeutic efficacy of cyanine dyes in the second near-infrared (NIR-II) biowindow are challenges in the biomedical field. Herein, we develop a metal ion-assisted NIR-II fluorophore assembly strategy to modulate molecular arrangement behavior, thus overcoming the drawbacks and retaining the photophysical performance of cyanine dyes in aqueous media for cancer phototheranostics. By screening a series of metal ion-assisted fluorophore assemblies, we remarkably found gadolinium-based metallo-dye-supramolecular nanoassembly (denoted as Gd@IR1064) with the intrinsic optical properties of NIR-II cyanine dye (IR1064). Most intriguingly, the as-prepared Gd@IR1064 not only exhibits deep-tissue-penetrating NIR-II photoacoustic, fluorescence, and magnetic resonance imaging ability but also possesses enhanced photothermal conversion performance-induced hyperthermia, achieving a significant tumor elimination effect. Our study provides a promising guide for modulating dye arrangement with unique photophysical performance for biomedical applications.