GEVIBench › All sensors › VSFP1
VSFP1
The first genetically encoded voltage indicator, establishing the VSFP architecture of pairing a voltage-sensing domain with a FRET fluorescent protein pair.
- Category: VSD-FRET GEVI
- Published: 2001-12-20 — European Journal of Neuroscience 2001
- Response polarity: positive-going (fluorescence increases on depolarization)
- Spectrum: excitation peak 435 nm, emission peak 529 nm (VSFP1)
- Tags: CFP/YFP, FRET
Headline values (as shown in the GEVIBench table)
| Metric | Value | Definition |
|---|---|---|
| Brightness (B/B_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) | 0.74 / 0.74 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 | +1.8% | 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 | 0.018% | 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 | — | 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) | — | Full width at half maximum of the optical spike waveform. |
| Photostability t75% @ 100 mW/mm² | — | 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) | 1 | 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 0.74 ms, τ_off 0.74 ms at 25-28°C — Sakai 2001, Fig. 3E
ΔF/F per 100 mV
- +1.8%, 1P — Sakai 2001, Fig. 3B
ΔF/F per mV (subthreshold)
- 0.018%/mV (Linear F-V slope = 1.8 ± 0.1%/100 mV = 0.018 %/mV (Sakai 2001 Fig. 3B, r=0.99, n=11). VSFP1's response is linear across the physiological range (no saturation), so its subthreshold slope equals its per-100-mV dynamic range.) — Sakai 2001, Fig. 3B
Fluorescence–voltage (F–V) curve
ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -100 mV: -0.5%; -70 mV: 0%; -50 mV: 0.3%; 0 mV: 1.2%; 50 mV: 2.1%; 100 mV: 3%; 150 mV: 3.8% — Sakai 2001, Fig. 3B
Research papers using VSFP1 (1)
- Design and characterization of a DNA-encoded, voltage-sensitive fluorescent protein — Sakai R, Repunte-Canonigo V, Raj CD, Knöpfel T, European Journal of Neuroscience 2001 (HEK 293 cells, in vitro)
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.