Anionic Conjugated Polyelectrolytes for FRET-based Imaging of Cellular Membrane Potential

Okhil K. Nag, Ji Eun Jeong, Van Sang Le, Eunkeu Oh, Han Young Woo, James B. Delehanty

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We report a Förster resonance energy transfer (FRET)-based imaging ensemble for the visualization of membrane potential in living cells. A water-soluble poly(fluorene-cophenylene) conjugated polyelectrolyte (FsPFc10) serves as a FRET donor to a voltage-sensitive dye acceptor (FluoVolt). We observe FRET between FsPFc10 and FluoVolt, where the enhancement in FRET-sensitized emission from FluoVolt is measured at various donor/acceptor ratios. At a donor/acceptor ratio of 1, the excitation of FluoVolt in a FRET configuration results in a three-fold enhancement in its fluorescence emission (compared to when it is excited directly). FsPFc10 efficiently labels the plasma membrane of HEK 293T/17 cells and remains resident with minimal cellular internalization for ~ 1.5 h. The successful plasma membrane-associated colabeling of the cells with the FsPFc10-FluoVolt donor-acceptor pair is confirmed by dual-channel confocal imaging. Importantly, cells labeled with FsPFc10 show excellent cellular viability with no adverse effect on cell membrane depolarization. During depolarization of membrane potential, HEK 293T/17 cells labeled with the donor-acceptor FRET pair exhibit a greater fluorescence response in FluoVolt emission relative to when FluoVolt is used as the sole imaging probe. These results demonstrate the conjugated polyelectrolyte to be a new class of membrane labeling fluorophore for use in voltage sensing schemes.

Original languageEnglish
Pages (from-to)834-844
Number of pages11
JournalPhotochemistry and Photobiology
Issue number4
Publication statusPublished - 2020 Jul 1

ASJC Scopus subject areas

  • Radiation
  • Biochemistry
  • Physical and Theoretical Chemistry


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