Yang Yang, Sun Caixia, Wang Shangfeng, Yan Kui, Zhao Mengyao, Wu Bin, Zhang Fan
Department of Chemistry, State Key Laboratory of Molecular Engineering of Polymers, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials and iChem, Fudan University, Shanghai, 200433, China.
Angew Chem Int Ed Engl. 2022 Jun 13;61(24):e202117436. doi: 10.1002/anie.202117436. Epub 2022 Apr 12.
Photon excitation and emission at the NIR-II spectral window enable high-contrast deep-tissue bioimaging. However, multiplexed imaging with NIR-II excitation and emission has been hampered by the limited chemical strategies to develop bright fluorophores with tunable absorption in this spectral regime. Herein, we developed a series of heptamethine cyanines (HCs) with varied absorption/emission maxima spanning from 1100 to 1600 nm through a physical organic approach. A bulky counterion paired to HCs was found to elicit substantial improvements in absorptivity (7-fold), brightness (14-fold), and spectral profiles in water, addressing a notorious quenching problem of NIR-II cyanines due to aggregation and polarization. We demonstrated the utilities of HC1222 and HC1342 for high-contrast dual-color imaging of circulatory system, lymphatic structures, tumor, and organ function in living mice under 1120 nm and 1319 nm excitation, showing HCs as a promising platform for non-invasive bioimaging.
在近红外二区（NIR-II）光谱窗口的光子激发和发射能够实现高对比度的深层组织生物成像。然而，由于在该光谱区域开发具有可调吸收的明亮荧光团的化学策略有限，利用NIR-II激发和发射进行多重成像受到了阻碍。在此，我们通过物理有机方法开发了一系列最大吸收/发射波长在1100至1600 nm之间变化的七甲川花菁（HCs）。发现与HCs配对的大体积抗衡离子可使吸光度（提高7倍）、亮度（提高14倍）以及在水中的光谱轮廓有显著改善，解决了由于聚集和极化导致的NIR-II花菁臭名昭著的猝灭问题。我们展示了HC1222和HC1342在1120 nm和1319 nm激发下对活体小鼠循环系统、淋巴结构、肿瘤和器官功能进行高对比度双色成像的效用，表明HCs是一个用于非侵入性生物成像的有前景的平台。
