Fluorescent probes based on π-conjugation modulation between hemicyanine and coumarin moieties for ratiometric detection of pH changes in live cells with visible and near-infrared channels

SENSORS AND ACTUATORS B-CHEMICAL

卷:265

Article

Xia, Shuai¹  Wang, Jianbo^1,2  Bi, Jianheng¹  Wang, Xiao¹  Fang, Mingxi¹  Phillips, Tyler¹  May, Asian¹  Conner, Nathan¹  Tanasova, Marina¹  Luo, Fen-Tair³  Liu, Haiying¹ 

[1] Michigan Technol Univ, Dept Chem, Houghton, MI 49931 USA

[2] Jiaxing Univ, Coll Biol Chem Sci & Engn, Jiaxing 314001, Peoples R China

[3] Acad Sinica, Inst Chem, Taipei 11529, Taiwan

关键词: Fluorescent probe;    Ratiometric imaging;    Near-infrared emission;    pH;    Live cells;   

DOI  :  10.1016/j.snb.2018.02.168

来源: Elsevier

【 摘 要 】

We report two ratiometric fluorescent probes based on pi-conjugation modulation between coumarin and hemicyanine moieties for sensitive ratiometric detection of pH alterations in live cells by monitoring visible and near-infrared fluorescence changes. In a pi-conjugation modulation strategy, a coumarin dye was conjugated to a near-infrared hemicyanine dye via a vinyl connection while lysosome-targeting morpholine ligand and o-phenylenediamine residue were introduced to the hemicyanine moieties to form closed spirolactam ring structures in probes A and B, respectively. The probes show only visible fluorescence of the coumarin moiety under physiological and basic conditions because the hemicyanine moieties retain their closed spirolactam ring structures. However, decrease of pH to acidic condition causes spirolactam ring opening, and significantly enhances pi-conjugation within the probes, thus generating new near-infrared fluorescence peaks of the hemicyanine at 755 nm and 740 nm for probes A and B, respectively. Moreover, the probes display ratiometric fluorescence response to pH with decreases of the coumarin fluorescence and increases of the hemicyanine fluorescence when pH changes from 7.4 to 2.5. The probes are fully capable of imaging pH changes in live cells with good ratiometric responses in visible and near-infrared channels, and effectively avoid fluorescence blind spots under neutral and basic pH conditions - an issue that typical intensity-based pH fluorescent probes run into. The probe design platform reported herein can be easily applied to prepare a variety of ratiometric fluorescent probes for detection of biological thiols, metal ions, reactive oxygen and nitrogen species by introducing appropriate functional groups to hemicyanine moiety. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

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