title: Dual Site-Controlled and Lysosome-Targeted Intramolecular Charge Transfer-Photoinduced Electron Transfer-Fluorescence Resonance Energy Transfer Fluorescent Probe for Monitoring pH Changes in Living Cells.
abstract: Acidic pH is a critical physiological factor for controlling the activities and functions of lysosome. Herein, we report a novel dual site-controlled and lysosome-targeted intramolecular charge transfer-photoinduced electron transfer-Fluorescence resonance energy transfer (ICT-PET-FRET) fluorescent probe (CN-pH), which was essentially the combination of a turn-on pH probe (CN-1) and a turn-off pH probe (CN-2) by a nonconjugated linker. Coumarin and naphthalimide fluorophores were selected as donor and acceptor to construct the FRET platform. Hydroxyl group and morpholine were simultaneously employed as the two pH sensing sites and controlled the fluorescence of coumarin and naphthalimide units by ICT and PET, respectively. The sensing mechanism of CN-pH to pH was essentially an integration of ICT, PET, and FRET processes. Meanwhile, the morpholine also can serve as a lysosome-targeted group. By combining the two data analysis approaches of the ratios of the two emission intensities (R) and the reverse ratio R' (R' = 1/R), the fluorescent ratio of CN-pH can show proportional relationship to pH values in a very broad range from pH 4.0 to 8.0 with high sensitivity. The probe has been successfully applied for the fluorescence imaging of the lysosomal pH values, as well as ratiometrically visualizing chloroquine-stimulated changes of intracellular pH in living cells. These features demonstrate that the probe can afford practical application in biological systems.
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Baoli
authors.initials: B
authors.lastname: Dong
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Xuezhen
authors.initials: X
authors.lastname: Song
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Xiuqi
authors.initials: X
authors.lastname: Kong
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Yonghe
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Institute of Fluorescent Probes for Biological Imaging, School of Chemistry and Chemical Engineering, School of Biological Science, University of Jinan , Jinan, Shandong 250022, People's Republic of China.
authors.forename: Weiying
authors.initials: W
authors.lastname: Lin
mesh_terms: D004579:Electron Transport; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure; D055668:Photochemical Processes; D011789:Quantum Theory; D014407:Tumor Cells, Cultured
chemical_list: D005456:Fluorescent Dyes