GEVIBench › All sensors › HVI
HVI
Chemigenetic GEVI that conjugates dyes to an Ace2 rhodopsin.
- Category: Chemigenetic GEVI
- Published: 2021-04-15 — Nature Chemistry 2021
- Response polarity: negative-going (fluorescence decreases on depolarization)
- Spectrum: excitation peak 553 nm, emission peak 569 nm (HVI (Cy3))
- Tags: Ace opsin, Cy3
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_EGFP) | 2.10× 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) | 1.7 / 2.5 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 | -39.1% (median of 3 measurements: −39.1%) | 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 | 0.28% | 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 | 25.3% (median of 3 measurements: 25.3%) | 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) | 12 ms | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | 1.2 min | 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) | 3 | 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 1.7 ms, τ_off 2.5 ms at 25°C — Liu 2021, Table S3
- τ_on 2.27 ms, τ_off 4.35 ms at 25°C — Liu 2025, Table S2
- τ_on 2.16 ms, τ_off 4.1 ms at 25°C — Liu 2025, Table S2
ΔF/F per 100 mV
- -39.1%, 1P, dye Cy3 — Liu 2021, Table S3
- -61.3%, 1P, dye Cy3b — Liu 2025, Table S2
- -19.6%, 1P, dye Cy5 — Liu 2021, Table S3
ΔF/F per mV (subthreshold)
- 0.28%/mV (HVI-Cy3: ΔF/F0 responses of −4.7 ± 0.1% and −2.2 ± 0.1% to depolarizing subthreshold steps of +16.9 and +7.8 mV, and +2.2 ± 0.1% and +4.8 ± 0.1% to hyperpolarizing steps of −7.4 and −17.2 mV, at a resting potential of ~−68 mV in cultured rat hippocampal neurons (484 Hz, 532 nm). |ΔF/F0|/|ΔV| ≈ 0.28 %/mV across all four steps.) — Liu 2021, Table S5
ΔF/F per action potential
- 25.3%, 1P, dye Cy3 — Liu 2021, Table S3
- -39.6%, 1P, dye Cy3b — Liu 2025, Table S2
- -12.8%, 1P, dye Cy5 — Liu 2021, Table S3
AP width (FWHM)
- 12 ms at 200 Hz sampling, Mouse, pancreatic islet α cells, ex vivo, 1P, 37°C — Liu 2025, Fig. 6F
Brightness comparisons
- 0.19× the brightness of Voltron — Liu 2021, Table S4
- 1.8867924528301885× the brightness of HVI+ — Liu 2025, Fig. S5C
Photobleaching
- t75% = 220 s at 49 mW/mm², 1P — Liu 2021, Ext. Fig. 4g
- t75% = 143 s at 50 mW/mm², 1P — Liu 2025, Fig. S7
- t75% = 42 s at 12 mW/mm², 1P — Liu 2021, Ext. Fig. 4g
Fluorescence–voltage (F–V) curve
ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -100 mV: 17%; -80 mV: 6%; -70 mV: 0%; -60 mV: -6%; -40 mV: -16%; -20 mV: -25%; 0 mV: -33%; 20 mV: -40%; 40 mV: -45%; 60 mV: -50% — Liu 2021, Fig. 2b
Research papers using HVI (3)
- A far-red hybrid voltage indicator enabled by bioorthogonal engineering of rhodopsin on live neurons — Liu S, Lin C, Xu Y, et al., Nature Chemistry 2021 (Human, HEK293T cells, in vitro; rat, hippocampal neurons, in vitro)
- Orange/far-red hybrid voltage indicators with reduced phototoxicity enable reliable long-term imaging in neurons and cardiomyocytes — Liu S, Ling J, Chen P, et al., Proceedings of the National Academy of Sciences 2023 (Rat, hippocampal neurons, in vitro; rat, cardiomyocytes, in vitro)
- Positive-going hybrid indicators for voltage imaging in excitable cells and tissues — Liu S, Ling J, Xie B, et al., Science Advances 2025 (Rat, hippocampal neurons, in vitro; mouse, pancreatic islets)
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.