Cai Songtao, Liu Qiuchen, Liu Chang, He Song, Zhao Liancheng, Zeng Xianshun, Gong Jin
Tianjin Key Laboratory for Photoelectric Materials and Devices, School of Materials Science & Engineering, Tianjin University of Technology, Tianjin, 300384, P. R. China.
Center for Biomedical Photonics & College of Physics and Optoelectronic Engineering, Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060, P. R. China.
J Mater Chem B. 2022 Feb 23;10(8):1265-1271. doi: 10.1039/d1tb02639a.
Xanthene-modified cyanine dyes are considered to be an effective means to extend the emission wavelength and improve the photo-stability of cyanine dyes. However, the fluorophores obtained by this strategy generally have narrow Stokes shifts, which severely limits their application in biological imaging. Herein, a reasonable design strategy is adopted to provide an effective strategy to commendably improve the Stokes shift of xanthene-benzothiozolium fluorophores the simultaneous expansion of a molecular π-conjugated system and heteroatomic substitution. Combined with density functional theory calculation guidance, the O atom is replaced with the S atom in the xanthene moiety and a π-conjugated benzene ring is introduced in the benzothiozolium moiety. Surprisingly, the results of the spectroscopic experiment showed that the fluorescence emission wavelength of PhCy-OH was extended to 803 nm, and the Stokes shift was improved to 68 nm. PhCy-Cys can effectively distinguish Cys from homocysteine (Hcy) and glutathione (GSH) with an extremely low detection limit of 0.166 μM. Importantly, PhCy-Cys has the ability to image endogenous Cys in mitochondria, providing the potential for exploring the specific function and mechanism of Cys in regulating oxidative stress in mitochondria.
呫吨修饰的花菁染料被认为是延长发射波长和提高花菁染料光稳定性的有效手段。然而，通过这种策略获得的荧光团通常具有较窄的斯托克斯位移，这严重限制了它们在生物成像中的应用。在此，采用了一种合理的设计策略，提供了一种有效的策略来显著提高呫吨-苯并噻唑鎓荧光团的斯托克斯位移——同时扩展分子π共轭体系和进行杂原子取代。结合密度泛函理论计算指导，在呫吨部分用S原子取代O原子，并在苯并噻唑鎓部分引入一个π共轭苯环。令人惊讶的是，光谱实验结果表明，PhCy-OH的荧光发射波长延长至803 nm，斯托克斯位移提高到68 nm。PhCy-Cys能够以极低的检测限0.166 μM有效地区分半胱氨酸（Cys）与同型半胱氨酸（Hcy）和谷胱甘肽（GSH）。重要的是，PhCy-Cys具有对线粒体中内源性Cys进行成像的能力，为探索Cys在调节线粒体氧化应激中的特定功能和机制提供了潜力。
