State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P.R. China.
Angew Chem Int Ed Engl. 2024 Oct 14;63(42):e202410666. doi: 10.1002/anie.202410666. Epub 2024 Sep 5.
Near-infrared region (NIR; 650-1700 nm) dyes offer many advantages over traditional dyes with absorption and emission in the visible region. However, developing new NIR dyes, especially organic dyes with long wavelengths, small molecular weight, and excellent stability and biocompatibility, is still quite challenging. Herein, we present a general method to enhance the absorption and emission wavelengths of traditional fluorophores by simply appending a charge separation structure, dihydropyridopyrazine. These novel NIR dyes not only exhibited greatly redshifted wavelengths compared to their parent dyes, but also displayed a small molecular weight increase together with retained stability and biocompatibility. Specifically, dye NIR-OX, a dihydropyridopyra-zine derivative of oxazine with a molecular mass of 386.2 Da, exhibited an absorption at 822 nm and an emission extending to 1200 nm, making it one of the smallest molecular-weight NIR-II emitting dyes. Thanks to its rapid metabolism and long wave-length, NIR-OX enabled high-contrast bioimaging and assessment of cholestatic liver injury in vivo and also facilitated the evalua-tion of the efficacy of liver protection medicines against cholestatic liver injury.
近红外区（NIR；650-1700nm）染料在吸收和发射方面优于传统的可见区染料，具有许多优点。然而，开发新的近红外染料，特别是具有长波长、小分子量、优异的稳定性和生物相容性的有机染料，仍然极具挑战性。在此，我们提出了一种通用的方法，通过简单地附加电荷分离结构二氢吡啶并[1,2-a]吡嗪，来增强传统荧光团的吸收和发射波长。与母体染料相比，这些新型近红外染料不仅表现出显著红移的波长，而且还表现出较小的分子量增加，同时保持稳定性和生物相容性。具体来说，二氢吡啶并[1,2-a]吡嗪衍生物 NIR-OX 是吖嗪的一种近红外-II 发射染料，分子量为 386.2Da，其吸收峰在 822nm 处，发射延伸至 1200nm，使其成为分子量最小的近红外-II 发射染料之一。由于其快速代谢和长波长，NIR-OX 能够实现高对比度的生物成像和体内胆汁淤积性肝损伤评估，并有助于评估针对胆汁淤积性肝损伤的保肝药物的疗效。
