GEVIBench › All sensors › Voltron2
Voltron2
Improved Voltron with enhanced sensitivity, retaining fast kinetics and photostability.
- Category: Chemigenetic GEVI
- Published: 2023-04-03 — Neuron 2023
- Derived from: Voltron
- Response polarity: negative-going (fluorescence decreases on depolarization)
- Spectrum: excitation peak 534 nm, emission peak 554 nm (Voltron2 (JF525))
- Two-photon compatible: yes
- Plasmid: Addgene #172909
- Tags: Ace opsin, HaloTag
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_EGFP) | 7.18× 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) | 4.0 / 5.5 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 | -34% (median of 5 measurements: −27%) | 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 | 0.51% | 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 | 10.09% (median of 4 measurements: 12%) | 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) | 3.2 ms | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | 42 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) | 23 | 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 1.5 ms, τ_off 3.05 ms at 23°C — Abdelfattah 2023, Fig. 2E
- τ_on 3.96 ms, τ_off 5.53 ms at 25°C — Liu 2025, Table S2
ΔF/F per 100 mV
- -34%, 1P, dye JF525 — Abdelfattah 2023, Fig. 2B
- -23%, 1P, dye JF525 — Cao 2025, Fig. 1C
- -21.2%, 1P, dye JF525 — Liu 2025, Table S2
- -22%, 1P, dye JF585 — Yang 2024, Fig. 1C
- -31%, 1P, dye JF525 — Hasseman 2022, Fig. 1
ΔF/F per mV (subthreshold)
- 0.54%/mV (Voltron2525 subthreshold slope 0.54%/mV ± 0.01%/mV in the −90 to −50 mV range (cultured neurons, n = 8 cells), an almost 3-fold higher slope than Voltron525 (0.21%/mV). Reported in the running main text; not a labeled figure panel (Fig. 3D is the synPSP sensitivity index d'/mV of Voltron2585, a different dye/metric).) — Abdelfattah 2023, Main text
- 0.48%/mV (Voltron2525-Kv subthreshold voltage-sensitivity slope ≈ 0.48 %/mV, read from the Fig. 5C comparison in the Hao et al. 2024 ASAP5 paper (soma-targeted Voltron2525-Kv, cultured rat hippocampal neurons), where the paper's primary sensor ASAP5-Kv is ≈ 0.83 %/mV. A different prep/metric from the origin-paper 0.54 %/mV entry above (that one is the −90→−50 mV subthreshold slope of un-targeted Voltron2525).) — Hao 2024, Fig. 5C
ΔF/F per action potential
- 10.09%, 1P, dye JF525 — Abdelfattah 2023, Fig. 2G
- 12%, 1P, dye JF525 — Liu 2025, Table S2
- 15%, 1P, dye JF525 — Hasseman 2022, Fig. 2
- 12.3%, 1P, dye JF585 — Yang 2024, Fig. 2B
AP width (FWHM)
- 3.2 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
- 7 ms at 484 Hz sampling, Rat, hippocampal neurons, in vitro, 1P, 25°C — Yang 2024, Fig. 2B
- 0.85 ms at 3500 Hz sampling, Mouse, cerebellar granular-layer Golgi/glycinergic interneurons, in vivo, awake, Voltron2-ST552 (JF552), 2P — Villette 2024, Fig. S9d
Brightness comparisons
- 0.65× the brightness of Voltron — Abdelfattah 2023, Fig. 2H
Photobleaching
- t75% = 307 s at 14.7 mW/mm², 1P — Abdelfattah 2023, Fig. 2I
- t75% = 83 s at 50 mW/mm², 1P — Liu 2025, Fig. S7
- t75% = 77 s (extrapolated) at 46 mW/mm², 1P — Hao 2024, Fig. S5E
- 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: 23%; -90 mV: 11%; -70 mV: 0%; -50 mV: -10%; -30 mV: -18%; -10 mV: -25%; 10 mV: -30%; 30 mV: -34%; 50 mV: -37% — Abdelfattah 2023, Fig. 2B
Research papers using Voltron2 (23)
- Sensitivity optimization of a rhodopsin-based fluorescent voltage indicator — Abdelfattah AS, et al., Neuron 2023 (Cultured neurons; flies, zebrafish, and mice, in vivo)
- Photophysics-informed two-photon voltage imaging using FRET-opsin voltage indicators — Brooks FP, et al., Science Advances 2025 (Mouse, barrel cortex, in vivo, two-photon)
- Imaging neuronal voltage beyond the scattering limit — Chen TW, et al., Nature Methods 2025 (Mouse, hippocampus CA1, in vivo)
- Large-scale deep tissue voltage imaging with targeted-illumination confocal microscopy — Xiao S, et al., Nature Methods 2024 (Mouse, cortex, in vivo)
- Two-photon voltage imaging with rhodopsin-based sensors — Grimm C, et al., Neuron 2026 (Mouse, hippocampal slices; zebrafish larvae; mouse cortex, in vivo, two-photon)
- Orange/far-red hybrid voltage indicators with reduced phototoxicity enable reliable long-term imaging in neurons and cardiomyocytes — Liu Y, et al., PNAS 2023 (Rat, hippocampal neurons, in vitro; cardiomyocytes, in vitro)
- Miniaturized widefield microscope for high speed in vivo voltage imaging — Saladrigas CA, et al., Biomedical Optics Express 2025 (Mouse, visual cortex interneurons, in vivo)
- Voltage imaging with periodic structured illumination — Speed F, et al., Biomedical Optics Express 2025 (Mouse, somatosensory, visual, and motor cortex, in vivo, Voltron2-JF552)
- Relative phase of membrane potential theta oscillations between individual hippocampal neurons code space — Athif M, et al., bioRxiv 2025 (Mouse, hippocampus CA1, in vivo)
- Dendritic excitations govern back-propagation via a spike-rate accelerometer — Park P, et al., Nature Communications 2025 (Mouse, hippocampus CA1 pyramidal neurons, acute brain slices, Optopatch-V (Voltron2-based))
- A fast and responsive voltage indicator with enhanced sensitivity for unitary synaptic events — Hao YA, et al., Neuron 2024 (Rat, hippocampal neurons, in vitro)
- Fast dendritic excitations primarily mediate back-propagation in CA1 pyramidal neurons during behavior — Lee BH, et al., bioRxiv 2026 (Mouse, hippocampus CA1 pyramidal neurons, in vivo, Voltron2-JF608)
- A dendrite-resolved, in vivo transfer function from spike patterns to dendritic Ca2+ — Wu X, et al., bioRxiv 2026 (Mouse, hippocampus CA2 pyramidal neurons, in vivo)
- A scalable, all-optical method for mapping synaptic connectivity with cell-type specificity — Moya MV, et al., bioRxiv 2025 (Mouse, motor cortex, acute brain slices, Voltron2-JF585)
- Voltage dynamics of dendritic integration and back-propagation in vivo — Wong-Campos JD, et al., bioRxiv 2023 (Mouse, barrel cortex L2/3, in vivo)
- High-speed multiplane confocal microscopy for voltage imaging in densely labeled neuronal populations — Weber TD, et al., Nature Neuroscience 2023 (Mouse, motor cortex, acute brain slices and in vivo, Voltron2-ST JF585)
- Fast and light-efficient remote focusing for volumetric voltage imaging — Bohm UL, Judkewitz B, Nature Communications 2024 (Zebrafish larvae, spinal cord, in vivo)
- All-optical reporting of inhibitory receptor driving force in the nervous system — Selfe JS, et al., Nature Communications 2024 (Mouse, hippocampal organotypic slices and somatosensory cortex L1, in vitro and in vivo, Voltron2-ST)
- Synchronous ensembles of hippocampal CA1 pyramidal neurons during novel exploration — Chen EL, et al., eLife 2025 (Mouse, hippocampus CA1 pyramidal neurons, in vivo, Voltron2-ST JF552)
- A novel rhodopsin-based voltage indicator for simultaneous two-photon optical recording with GCaMP in vivo — Villette V, et al., bioRxiv 2024 (Rat, hippocampal neurons, in vitro; mouse, cerebellum Golgi cells, in vivo, two-photon, Voltron2-ST JF552)
- Positive-going hybrid indicators for voltage imaging in excitable cells and tissues — Liu S, et al., Science Advances 2025 (HEK293T cells and rat hippocampal neurons, in vitro; Voltron2525 (JF525) characterized head-to-head as a comparator to HVI+ (kinetics/dynamic range/sensitivity Table S2, photobleaching Fig. S7))
- Solaris: a panel of bright and sensitive hybrid voltage indicators for imaging membrane potential in cultured neurons — Yang J, et al., bioRxiv 2024 (HEK293T cells and rat hippocampal neurons, in vitro; Voltron2585 (JF585) characterized as a comparator to the Solaris dye series (dynamic range, per-AP sensitivity, kinetics))
- A photostable genetically encoded voltage indicator for imaging neural activities in tissue and live animals — Cao C, et al., bioRxiv 2025 (HEK293T cells; Voltron2525 (JF525) measured as a comparator (dynamic range −27.5%/100 mV, Fig. 1C) to the Vega indicator)
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.