Voltron

Breakthrough chemigenetic GEVI that binds fluorescent dyes with exceptional brightness and photostability.

Category: Chemigenetic GEVI
Published: 2019-08-16 — Science 2019
Response polarity: negative-going (fluorescence decreases on depolarization)
Spectrum: excitation peak 534 nm, emission peak 554 nm (Voltron (JF525))
Plasmid: Addgene #119033
Tags: Ace opsin, HaloTag

Headline values (as shown in the GEVIBench table)

Metric	Value	Definition
Brightness (B/B_EGFP)	11.04× EGFP	Molecular brightness relative to EGFP (extinction coefficient × quantum yield, or a measured ratio). Sensors not measured against EGFP directly are placed through a chain of pairwise brightness comparisons, combined by geometric mean.
Kinetics τ_on / τ_off (ms)	2.0 / 2.2 ms	Activation / decay time constants in ms (amplitude-weighted mean τ for multi-exponential fits). The value shown averages the measurements made at physiological temperature (≥33 °C); if there are none, it is the measurement closest to 33 °C.
ΔF/F per 100 mV	-23% (median of 8 measurements: −23%)	Steady-state fluorescence change for a 100 mV depolarization step (−70 → +30 mV); the sign gives the polarity. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting.
ΔF/F per mV	0.21%	Subthreshold sensitivity: fluorescence change per mV near rest (−90 to −50 mV). Where no value is reported directly, it is estimated from the F–V curve.
ΔF/F per AP	6.16% (median of 3 measurements: 6.5%)	Fluorescence change per single action potential in neurons. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting.
AP width (FWHM, ms)	3 ms	Full width at half maximum of the optical spike waveform.
Photostability t75% @ 100 mW/mm²	25 s	Time for fluorescence to fall to 75% of its initial value under one-photon illumination, linearly dose-scaled to 100 mW/mm² (t50% is used where the 75% crossing falls inside a fast initial transient). Two-photon curves are not dose-scaled and are excluded.
Papers using it (N_used)	9	Number of published research papers, tracked by GEVIBench, that used the sensor for an experiment (a popularity / track-record measure).

Measurements and sources

Kinetics

τ_on 1.99 ms, τ_off 2.18 ms at 25°C — Abdelfattah 2019, Table S3
τ_on 2 ms, τ_off 3.19 ms at 23°C — Abdelfattah 2023, Fig. 2E

ΔF/F per 100 mV

-23%, 1P, dye JF525 — Abdelfattah 2019, Fig. 1E
-23%, 1P, dye JF525 — Abdelfattah 2020, Fig. 2a
-18.5%, 1P, dye JF525 — Hasseman 2022, Fig. 1
-17.1%, 1P, dye JF585 — Yang 2024, Fig. 1C
-16%, 1P, dye JF503 — Abdelfattah 2019, Fig. 1E
-18%, 1P, dye JF549 — Abdelfattah 2019, Fig. 1E
-18%, 1P, dye JF585 — Abdelfattah 2019, Fig. 1E
-8%, 1P, dye JF635 — Abdelfattah 2019, Fig. 1E

ΔF/F per mV (subthreshold)

0.21%/mV (Voltron525 subthreshold slope 0.21%/mV ± 0.01%/mV in the −90 to −50 mV range (cultured neurons, n=8 cells), reported in the running main text of the Voltron2 paper as the comparator to Voltron2525 (0.54%/mV). Not a labeled figure panel (Fig. 2B is the F-V curve).) — Abdelfattah 2023, Main text

ΔF/F per action potential

6.16%, 1P, dye JF525 — Abdelfattah 2023, Fig. 2G
6.5%, 1P, dye JF525 — Piatkevich 2019, Ext. Fig. 5c
6.5%, 1P, dye JF525 — Hasseman 2022, Fig. 2

AP width (FWHM)

3 ms at 985 Hz sampling, Cultured rat hippocampal neurons, uM Workstation whole-cell current clamp, single evoked AP (2 nA, 2 ms pulse), 1P, 23°C — Abdelfattah 2023, Fig. 2F

Brightness comparisons

4× the brightness of Ace2N-mNeon — Abdelfattah 2019, Fig. 1F
5.2631578947368425× the brightness of HVI — Liu 2021, Table S4
1.6949152542372883× the brightness of Positron — Abdelfattah 2020, Fig. 2b
1.5384615384615383× the brightness of Voltron2 — Abdelfattah 2023, Fig. 2H

Photobleaching

t75% = 30.5 s at 25 mW/mm² (510/25 nm), 1P — Piatkevich 2019, Ext. Fig. 5e
t75% = 61 s at ~23 mW/mm² (510/25 nm), 1P — Abdelfattah 2019, Fig. 1H
t75% = 245 s at 14.7 mW/mm² (510/25 nm), 1P — Abdelfattah 2023, Fig. 2I
curve only (did not reach 75% within the measured window) at 70–140 mW/mm² (DMD patterned, per-cell), 1P — Abdelfattah 2023, Fig. S8d

Fluorescence–voltage (F–V) curve

ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -110 mV: 8%; -90 mV: 4.5%; -70 mV: 0%; -50 mV: -4.5%; -30 mV: -9%; -10 mV: -13.5%; 10 mV: -18%; 30 mV: -22.5%; 50 mV: -27% — Abdelfattah 2019, Fig. 1E

Research papers using Voltron (9)

Bright and photostable chemigenetic indicators for extended in vivo voltage imaging — Abdelfattah AS, Kawashima T, Singh A, et al., Science 2019 (Mouse cortex L1, larval zebrafish, Drosophila, in vivo; HEK cells)
High-fidelity estimates of spikes and subthreshold waveforms from 1-photon voltage imaging in vivo — Xie ME, et al., Cell Reports 2021 (Mouse, somatosensory cortex layer 1, in vivo)
VolPy: Automated and scalable analysis pipelines for voltage imaging datasets — Cai C, et al., PLOS Computational Biology 2021 (Mouse cortex L1 and larval zebrafish tegmentum, in vivo)
Single Photon Kilohertz Frame Rate Imaging of Neural Activity — Tian T, Yuan Y, Mitra S, et al., Advanced Science 2022 (Rat, hippocampal CA1, acute brain slices, Voltron-JF525)
Voltage-Seq: all-optical postsynaptic connectome-guided single-cell transcriptomics — Csillag V, et al., Nature Methods 2023 (Mouse, periaqueductal gray (PAG), acute brain slices, Voltron-ST + JF585)
All-optical voltage imaging-guided postsynaptic single-cell transcriptome profiling with Voltage-Seq — Csillag V, Noble JC, Calvigioni D, et al., Nature Protocols 2024 (Mouse, acute brain slices, Voltron-ST)
Dynamic assemblies of parvalbumin interneurons in brain oscillations — Huang YC, et al., Neuron 2024 (Mouse, hippocampal CA1, PV interneurons, in vivo)
Optical Recordings of Unitary Synaptic Connections Reveal High and Random Local Connectivity between CA3 Pyramidal Cells — Layous R, et al., Journal of Neuroscience 2025 (Rat, hippocampal CA3 pyramidal cells, acute brain slices, Voltron-ST + JF549)
Voltage imaging reveals circuit computations in the raphe underlying serotonin-mediated motor vigor learning — Kawashima T, et al., Neuron 2025 (Larval zebrafish, serotonergic raphe (DRN), in vivo)

Data and citation

llms.txt — summary for language models
llms-full.txt — every sensor in full (Markdown)
gevis.json — all values and measurements with sources (JSON)
gevis.csv — one row per sensor (CSV)

Cite GEVIBench as: Adam E. Cohen and Daozheng Gong (2026). Voltage imaging: A practical guide. Neuron. https://doi.org/10.1016/j.neuron.2026.08.002

Generated from the GEVIBench database on 2026-10-12.