The Synthesis of ESIPT-Based Fluorescent Dyes with Large Stokes Shifts and Their Applications in Cell Imaging

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Gül S., Kuzu B., Genç H., Tan Uygun M., Mengeş N.

International 10. Drug Chemistry Conference, Antalya, Turkey, 10 - 13 March 2022, pp.44

  • Publication Type: Conference Paper / Summary Text
  • City: Antalya
  • Country: Turkey
  • Page Numbers: pp.44
  • Van Yüzüncü Yıl University Affiliated: Yes


Developing small fluorescent organic dyes with large Stokes shifts, which can minimize cross-talk between the excitation source and the fluorescent emission for cellular imaging, is crucial in cell imaging to probe biological dynamics and monitor RNA and DNA at the cellular level.1 In our previous studies related to the ESIPT mechanism, we found that compounds with disubstituted imidazole rings have remarkable fluorescence properties and large Stokes shifts. One of our imidazole derivatives (Bk6) was a fluorescence sensor sensitive to intracellular pH changes, with a Stokes shift of 143 nanometres, and another derivative was sensitive to Fe3+ ions with a Stokes shift of 107 nm. 2 In addition, the commercially available fluorescent organic dyes, such as nil red dyes, cyanine dyes, have Stokes shifts below 70 nm and lead to undesired background interferences.3 To cope with this issue, we developed a series of possible fluorophore dyes with large Stokes shifts (Δλ ≥ 100 nm), as well as a fluorescence library of mono- and di-substituted imidazole molecules, to examine the intracellular fluorescence dye properties of the molecules with the best fluorescence activity. As a result, ten of the synthesized molecules showed Stokes shifts greater than 100 nm and their emissions were higher than 500 nm. Molecule C, our most active molecule, had an emission at 620 nm, while the Stokes shift is 224 nm. Cell imaging experiments will be conducted on the various live cell lines with different molecules.