Two-step energy transfer dynamics in conjugated polymer and dye-labeled aptamer-based potassium ion detection assay

Inhong Kim, Ji Eun Jung, Woojin Lee, Seongho Park, Heedae Kim, Young Dahl Jho, Han Young Woo, Kwangseuk Kyhm

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We recently implemented highly sensitive detection systems for photo-sensitizing potassium ions (K+) based on two-step Förster resonance energy transfer (FRET). As a successive study for quantitative understanding of energy transfer processes in terms of the exciton population, we investigated the fluorescence decay dynamics in conjugated polymers and an aptamer-based 6-carboxyfluorescein (6-FAM)/6-carboxytetramethylrhodamine (TAMRA) complex. In the presence of K+ ions, the Guanine-rich aptamer enabled efficient two-step resonance energy transfer from conjugated polymers to dyed pairs of 6-FAMand TAMRAthrough the G-quadruplex phase. Although the fluorescence decay time of TAMRA barely changed, the fluorescence intensity was significantly increased. We also found that 6-FAM showed a decreased exciton population due the compensation of energy transfer to TAMRA by FRET from conjugated polymers, but a fluorescence quenching also occurred concomitantly. Consequently, the fluorescence intensity of TAMRA showed a 4-fold enhancement, where the initial transfer efficiency (~300%) rapidly saturated within ~0.5 ns and the plateau of transfer efficiency (~230%) remained afterward.

Original languageEnglish
Article number1206
Issue number7
Publication statusPublished - 2019 Jul 1

Bibliographical note

Funding Information:
Funding: This research was supported by a two-year research grant from Pusan National University.

Publisher Copyright:
© 2019 by the authors.


  • FRET
  • Potassium ion detection
  • Time-resolved photoluminescence
  • Two-step FRET

ASJC Scopus subject areas

  • General Chemistry
  • Polymers and Plastics


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