Near-infrared II chalcogenonium salt chromophores: Recent advances in imaging, biosensing, and therapeutic applications

초록

The second near-infrared (NIR-II) biological window offers distinctive advantages for biomedical imaging and therapy, including enhanced spatial resolution, deeper tissue penetration, and improved laser safety. Chalcogenonium salt chromophores represent a highly versatile molecular platform, offering extensive tunability of optical properties through judicious heteroatom (O/S) selection, It-conjugation modulation, donor-acceptor engineering, and steric encumbrance control. This review provides a comprehensive overview of the chemical structures, photophysical properties, and biomedical applications of two prominent chromophore classes: pyrylium and thiopyrylium salts. These NIR-II dyes enable high-precision multi-scale imaging with significant potential for image-guided surgery, photothermal/photodynamic/sonodynamic therapy. However, key challenges remain, including the emission redshift-radiative efficiency trade-off, limited therapeutic scope, and clinical translation barriers. Future research should emphasize developing brighter emitters, constructing integrated theranostic platforms, and expanding therapeutic modalities.

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