Finely Tuned, Meticulously Screened Renal-Clearable Zwitterionic Cyanine Dyes for Targeted NIR-II Tumor Detection, Intraoperative Navigation, and Dual-Color Imaging.

Achieving clear near-infrared-II (NIR-II, 1000-1700 nm) imaging requires dyes that selectively target tissues while clearing rapidly from nontarget areas to reduce background noise. Based on zwitterionic cyanine molecules, heteroatom substitutions (O, N, S) and bridging ring modification (hexene or pentene) were employed to fine-tune emission and brightness within the NIR-II range. The optimized dye, , demonstrated a large Stokes shift (70 nm), high brightness (692 M cm), rapid renal clearance, and excellent biocompatibility. Conjugation with αβ integrin-targeting ligands enabled superior tumor imaging in 4T1, U87, and A549 tumor-bearing mouse models, achieving tumor-to-muscle ratios of over 5. Additionally, conjugation with prostate-specific membrane antigen ligands allowed precise prostate cancer diagnostics. The dye demonstrated exceptional potential for intraoperative navigation, allowing for precision tumor margins distinguishment and tiny residual tumorous tissues detection. Integrating with an NIR-II excitable probe enabled real-time, multitarget imaging for precise tumor resection and tissue preservation during surgery.