Shop All Voltage & Membrane Potential Sensors

DiSBAC2(3)

Voltage Sensor Probes (VSPs) are a Fluorescence Resonance Energy Transfer (FRET)-based voltage-sensing assay technology used to measure changes in cellular membrane electrical potential. VSPs are ideal for screening compounds that modulate ion channels because they provide:

• High-throughput capabilities-screen 32,000 samples in one day
• Highly sensitive detection-accurately and precisely report a 1% change in the Emission Ratio per mV
• Rapid detection response-sub-second time response
• Ratiometric readout (the Emission Ratio)-reduces experimental errors arising from well-to-well variations in
• cell number, addition artifacts, dye loading, plate inconsistencies, temperature fluctuations, and signal intensities. Allows for highly accurate, real-time optical readout of changes in membrane potential
• Universal methodology-applicable to any target that changes the membrane potential
• Highly accurate, real-time optical readout-results correlate with patch clamp data

How VSPs Work
VSPs use a FRET pair composed of one of two highly fluorescent, mobile, voltage-sensitive acceptor oxonols [DiSBAC2(3) or DiSBAC4(3)] and a fluorescent, membrane-bound coumarinphospholipid FRET donor (CC2-DMPE). When the cell interior has a relatively negative potential, the oxonol dye will bind to the exterior of the cell membrane, resulting in efficient FRET. When the cell interior has a relatively positive potential, however,
the oxonol dye will bind to the interior of the cell membrane, thus separating the FRET pair and disrupting FRET.

DiSBAC2(3) is used for most ion channel screening applications because it is more sensitive, easier to load, more stable than DiSBAC4(3), and can remain in the extracellular media. The time response of this oxonol is ~500 ms. DiSBAC4(3) requires a surfactant for cellular loading and a washing step to remove excess dye, but responds to changes to the membrane potential in ~20 ms. This dye is useful for applications that require faster response time or no added dye in the extracellular solution.

VABSC-1 Dye (Voltage Assay Background Suppression Compound) performs in conjunction with CC2-DMPE to suppress background signal, providing optimal performance and minimal toxicity.

DiSBAC2(3) (Bis-(1,3-Diethylthiobarbituric Acid)Trimethine Oxonol) (Invitrogen™)

The slow-response potential-sensitive probe, DiSBAC2(3) can enter depolarized cells where it binds to intracellular proteins or membrane and exhibits enhanced fluorescence and a red spectral shift. Increased depolarization results in additional influx of the anionic dye and an increase in fluorescence. Conversely, hyperpolarization is indicated by a decrease in fluorescence. Potential-dependent fluorescence changes generated by this bis-oxonol are typically ~1% per mV. Also, this probe has an excitation maxima of 530 nm and emission maxima of 560 nm. DiBAC dyes are excluded from mitochondria because of their overall negative charge, making them superior to carbocyanines for measuring plasma membrane potentials.

VABSC-1 Dye (Voltage Assay Background Suppression Compound)

Voltage Sensor Probes (VSPs) are a Fluorescence Resonance Energy Transfer (FRET)-based voltage-sensing assay technology used to measure changes in cellular membrane electrical potential. VSPs are ideal for screening compounds that modulate ion channels because they provide:

• High-throughput capabilities-screen 32,000 samples in one day
• Highly sensitive detection-accurately and precisely report a 1% change in the Emission Ratio per mV
• Rapid detection response-sub-second time response
• Ratiometric readout (the Emission Ratio)-reduces experimental errors arising from well-to-well variations in
• cell number, addition artifacts, dye loading, plate inconsistencies, temperature fluctuations, and signal intensities. Allows for highly accurate, real-time optical readout of changes in membrane potential
• Universal methodology-applicable to any target that changes the membrane potential
• Highly accurate, real-time optical readout-results correlate with patch clamp data

How VSPs Work
VSPs use a FRET pair composed of one of two highly fluorescent, mobile, voltage-sensitive acceptor oxonols [DiSBAC2(3) or DiSBAC4(3)] and a fluorescent, membrane-bound coumarinphospholipid FRET donor (CC2-DMPE). When the cell interior has a relatively negative potential, the oxonol dye will bind to the exterior of the cell membrane, resulting in efficient FRET. When the cell interior has a relatively positive potential, however,
the oxonol dye will bind to the interior of the cell membrane, thus separating the FRET pair and disrupting FRET.

DiSBAC2(3) is used for most ion channel screening applications because it is more sensitive, easier to load, more stable than DiSBAC4(3), and can remain in the extracellular media. The time response of this oxonol is ~500 ms. DiSBAC4(3) requires a surfactant for cellular loading and a washing step to remove excess dye, but responds to changes to the membrane potential in ~20 ms. This dye is useful for applications that require faster response time or no added dye in the extracellular solution.

VABSC-1 Dye (Voltage Assay Background Suppression Compound) performs in conjunction with CC2-DMPE to suppress background signal, providing optimal performance and minimal toxicity.

BacLight™ Bacterial Membrane Potential Kit (Invitrogen™)

The BacLight™ Bacterial Membrane Potential Kit provides the fluorescent membrane-potential indicator dye, DiOC2(3), along with a proton ionophore (CCCP) and premixed buffer. DiOC2(3) at low concentrations exhibits green fluorescence in all bacterial cells, but it becomes more concentrated in healthy cells that are maintaining a membrane potential, causing the dye to self-associate and the fluorescence emission to shift to red. The red- and green-fluorescent bacterial populations are easily distinguished using a flow cytometer. CCCP is included in the kit for use as a control because it eradicates the proton gradient, eliminating bacterial membrane potential.

View additional information about all microbiology assays for flow cytometry.

DiBAC4(3) (Bis-(1,3-Dibutylbarbituric Acid)Trimethine Oxonol) (Invitrogen™)

The slow-response potential-sensitive probe, DiBAC4(3) can enter depolarized cells where it binds to intracellular proteins or membrane and exhibits enhanced fluorescence and a red spectral shift. Increased depolarization results in additional influx of the anionic dye and an increase in fluorescence. Conversely, hyperpolarization is indicated by a decrease in fluorescence. This bis-oxonal has an excitation maxima of 490 nm and emission maxima of 516 nm. DiBAC dyes are excluded from mitochondria because of their overall negative charge, making them superior to carbocyanines for measuring plasma membrane potentials.

CC2-DMPE (voltage sensor probe)

Voltage Sensor Probes (VSPs) are a Fluorescence Resonance Energy Transfer (FRET)-based voltage-sensing assay technology used to measure changes in cellular membrane electrical potential. VSPs are ideal for screening compounds that modulate ion channels because they provide:

• High-throughput capabilities-screen 32,000 samples in one day
• Highly sensitive detection-accurately and precisely report a 1% change in the Emission Ratio per mV
• Rapid detection response-sub-second time response
• Ratiometric readout (the Emission Ratio)-reduces experimental errors arising from well-to-well variations in
• cell number, addition artifacts, dye loading, plate inconsistencies, temperature fluctuations, and signal intensities. Allows for highly accurate, real-time optical readout of changes in membrane potential
• Universal methodology-applicable to any target that changes the membrane potential
• Highly accurate, real-time optical readout-results correlate with patch clamp data

How VSPs Work
VSPs use a FRET pair composed of one of two highly fluorescent, mobile, voltage-sensitive acceptor oxonols [DiSBAC2(3) or DiSBAC4(3)] and a fluorescent, membrane-bound coumarinphospholipid FRET donor (CC2-DMPE). When the cell interior has a relatively negative potential, the oxonol dye will bind to the exterior of the cell membrane, resulting in efficient FRET. When the cell interior has a relatively positive potential, however,
the oxonol dye will bind to the interior of the cell membrane, thus separating the FRET pair and disrupting FRET.

DiSBAC2(3) is used for most ion channel screening applications because it is more sensitive, easier to load, more stable than DiSBAC4(3), and can remain in the extracellular media. The time response of this oxonol is ~500 ms. DiSBAC4(3) requires a surfactant for cellular loading and a washing step to remove excess dye, but responds to changes to the membrane potential in ~20 ms. This dye is useful for applications that require faster response time or no added dye in the extracellular solution.

VABSC-1 Dye (Voltage Assay Background Suppression Compound) performs in conjunction with CC2-DMPE to suppress background signal, providing optimal performance and minimal toxicity.

Voltage Sensor Probes Set, DiSBAC2(3) and CC2-DMPE

Voltage Sensor Probes (VSPs) are a Fluorescence Resonance Energy Transfer (FRET)-based voltage-sensing assay technology used to measure changes in cellular membrane electrical potential. VSPs are ideal for screening compounds that modulate ion channels because they provide:

• High-throughput capabilities-screen 32,000 samples in one day
• Highly sensitive detection-accurately and precisely report a 1% change in the Emission Ratio per mV
• Rapid detection response-sub-second time response
• Ratiometric readout (the Emission Ratio)-reduces experimental errors arising from well-to-well variations in
• cell number, addition artifacts, dye loading, plate inconsistencies, temperature fluctuations, and signal intensities. Allows for highly accurate, real-time optical readout of changes in membrane potential
• Universal methodology-applicable to any target that changes the membrane potential
• Highly accurate, real-time optical readout-results correlate with patch clamp data

How VSPs Work
VSPs use a FRET pair composed of one of two highly fluorescent, mobile, voltage-sensitive acceptor oxonols [DiSBAC2(3) or DiSBAC4(3)] and a fluorescent, membrane-bound coumarinphospholipid FRET donor (CC2-DMPE). When the cell interior has a relatively negative potential, the oxonol dye will bind to the exterior of the cell membrane, resulting in efficient FRET. When the cell interior has a relatively positive potential, however,
the oxonol dye will bind to the interior of the cell membrane, thus separating the FRET pair and disrupting FRET.

DiSBAC2(3) is used for most ion channel screening applications because it is more sensitive, easier to load, more stable than DiSBAC4(3), and can remain in the extracellular media. The time response of this oxonol is ~500 ms. DiSBAC4(3) requires a surfactant for cellular loading and a washing step to remove excess dye, but responds to changes to the membrane potential in ~20 ms. This dye is useful for applications that require faster response time or no added dye in the extracellular solution.

VABSC-1 Dye (Voltage Assay Background Suppression Compound) performs in conjunction with CC2-DMPE to suppress background signal, providing optimal performance and minimal toxicity.