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

Bibliographical note

Funding Information:
The authors acknowledge the NRL Base Funding Program and the NRL Institute for Nanoscience for financial support. H.Y.W. acknowledges the financial support from the National Research Foundation (NRF) of Korea (2019R1A2C2085290, 2019R1A6A1A11044070).

Publisher Copyright:
© 2020 American Society for Photobiology

ASJC Scopus subject areas

  • Radiation
  • Biochemistry
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Anionic Conjugated Polyelectrolytes for FRET-based Imaging of Cellular Membrane Potential'. Together they form a unique fingerprint.

Cite this