Optical measurement of absolute membrane potential and growth-factor-induced hyperpolarization
Membrane potential can be read optically with voltage-sensitive dyes. Lazzari-Dean, Gest and Miller (2019) developed VF-FLIM, which uses the fluorescence lifetime of VoltageFluor dyes to estimate absolute potential in single cells, with patch clamp as the standard.3 Bonzanni and colleagues (2020) note that patch clamping is technically challenging, low-throughput and not widely available.6
- Earliest held
- 2008, Sundelacruz S, Levin M…
- Most discussed in
- Optical estimation of absolute membrane…, 2019
- In the library
- 67 passages in 17 works
- Rewritten
- 2026-10-09
VoltageFluor dyes
Dolenšek and colleagues (2015) reviewed a family of dyes called VoltageFluor, which work by photo-induced electron transfer. At the hyperpolarized resting potential, the local electric field promotes electron transfer to the fluorophore, which quenches its fluorescence.1 When the membrane depolarizes, electron transfer becomes less favorable and fluorescence rises. The review reports sensitivity of up to 48% change in fluorescence per 100 mV, about a two-fold improvement over the best earlier dyes.1 In the same year Özkucur and colleagues, working with neurons and astrocytes, measured membrane potential with both voltage-sensitive dyes and whole-cell patch clamping.2
Lifetime as a reference
Lazzari-Dean, Gest and Miller (2019) argued that fluorescence lifetime is intrinsic to the dye, so it supplies a point of reference. A single lifetime image can then be read as resting membrane potential.4 Against patch clamp, they report single-trial accuracy of 10 to 23 mV with a 15 s acquisition, depending on the cell line.3 They report resolution as the root-mean-square deviation from the clamped voltage.4 They also report an 8-fold gain over ratiometric strategies and a 19-fold gain over other lifetime-based strategies.5 They state that the method is limited to acquisition speeds on the order of seconds.3
Use in cells and tissues
Other groups apply dyes to ask what sets resting potential in a given cell or tissue. Bonzanni and colleagues (2020) replaced permeable ions with non-permeable ones and followed the resulting changes with both patch clamp and a dye, in an epithelial and a cancer cell line.6 Kapsetaki and colleagues (2025) used the dyes FluoVolt and VF2.1.Cl to build a whole-body bioelectric atlas of hydra, with a consistently depolarized foot.8
Open problems
Desoyer and colleagues (2026) point out that methods differ between laboratories. Variability in how membrane potential is measured is described as a significant challenge.9 The passages held here do not report growth-factor experiments, so the article cannot say what epidermal growth factor does to membrane potential. They show only that dye-based and lifetime-based readouts exist, that they have been checked against patch clamp, and that their accuracy depends on the cell line.3
At the hyperpolarized resting potential, the local electric field promotes electron transfer from the electron donor on the molecular wire to the fluorophore, in turn quenching the fluorescence of the fluorophore.
Dolenšek J, Špelič D, Klemen MS, Žalik B, Gosak M, Rupnik…, 2015 · Membrane Potential and Calcium Dynamics in Beta Cells from Mouse Pancreas… · open at passage 21Vmem was measured using voltage-sensitive dyes and whole-cell patch clamping.
Özkucur N, Quinn KP, Pang JC, Du C, Georgakoudi I, Miller…, 2015 · Membrane potential depolarization causes alterations in neuron arrangement and… · open at passage 1VF-FLIM reports absolute membrane potential in single trials with 10 to 23 mV accuracy (root mean square deviation, RMSD; 15 s acquisition), depending on the cell line.
Lazzari-Dean JR, Gest AM, Miller EW, 2019 · Optical estimation of absolute membrane potential using fluorescence lifetime… · open at passage 7The intrinsic nature of fluorescence lifetime introduces a point of reference into the voltage measurement, from which a single lifetime image can be interpreted as resting membrane potential.
Lazzari-Dean JR, Gest AM, Miller EW, 2019 · Optical estimation of absolute membrane potential using fluorescence lifetime… · open at passage 69We benchmark VF-FLIM against previously reported optical absolute Vmem recording approaches and demonstrate resolution improvements of 8-fold over ratiometric strategies and 19-fold over other lifetime-based strategies.
Lazzari-Dean JR, Gest AM, Miller EW, 2019 · Optical estimation of absolute membrane potential using fluorescence lifetime… · open at passage 7Current approaches to measure the RMP rely on patch clamping, which is technically challenging, low-throughput and not widely available.
Bonzanni M, Payne SL, Adelfio M, Kaplan DL, Levin M, Oudin…, 2020 · Defined extracellular ionic solutions to study and manipulate the cellular… · open at passage 0The dissociated melanophores of jag are more depolarized when measured with a voltage-sensitive dye, DiBAC4(3), than the melanophores from wildtype fish.
Silic MR, Zhang G, 2023 · Bioelectricity in Developmental Patterning and Size Control: Evidence and… · open at passage 26The consensus whole-body bioelectric atlas of immortal hydra shows a consistently depolarized foot and occasionally depolarized tentacles.
Kapsetaki SE, Pimkina A, McMillen P, Tayyebi P, Erickson P…, 2025 · The Bioelectrics of Immortality and Mortality in Cold-Sensitive <i>Hydra… · open at passage 2In addition, methodological variability in V m measurement presents a significant challenge.
Desoyer C, Šupe R, Ghorbanpour S, Goswami D, Khalaj M…, 2026 · Cancer: A bioelectric disease? · open at passage 113