Shop All Cellular Sensors & Indicators

Phen Green™ SK, Diacetate Invitrogen™

The green-fluorescent heavy metal indicator Phen Green™ SK, diacetate can be used to detect a broad range of ions, including Cu2+, Cu+, Fe2+, Hg2+, Pb2+, Cd2+, Zn2+ and Ni2+.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Mag-Fluo-4, AM, cell permeant - Special Packaging Invitrogen™

The cell-permeant mag-fluo-4, AM is an analog of fluo-4 with a Kd for Mg2+ of 4.7 mM and a Kd for Ca2+ of 22 µM, making it useful as an intracellular Mg2+ indicator as well as a low-affinity Ca2+ indicator.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Fura-2, Pentapotassium Salt, cell impermeant Invitrogen™

Fura-2, pentapotassium salt is an intracellular calcium indicator that is ratiometric and UV light-excitable. This water-soluble salt form is useful for intracellular loading by microinjection, infusion from patch pipette or uptake induced by our Influx pinocytic cell-loading reagent (I14402).

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Fluo-4 NW Calcium Assay Kit Invitrogen™

Fluo-4 NW (No-Wash) Calcium Assay Kitsoffer a proprietary calcium assay formulation that requires neither a washstep nor a quencher dye. The fluo-4 NW assay achieves largerincreases in fluorescence intensity than standard fluo-3 and fluo-4assays with a wash step. Eliminating the wash step results inlower variability and higher Z´ values than the standard fluo-4 assay,while providing an easier and faster assay as well.

The fluo-4NW indicator is nonfluorescent and stable in pH 7–7.5 buffer forseveral hours, so spontaneous conversion to the Ca2+-sensitive formis not a significant source of background fluorescence. Contributionsto baseline fluorescence by the growth medium (e.g., esteraseactivity, proteins interacting with receptors of interest, or phenolred) are eliminated by removing the medium prior to adding theindicator dye to the wells.

Another source of potential fluorescenceoutside the cells is extrusion of the indicator out of the cell by organicanion transporters. Probenecid is commonly used to inhibitthis transport and reduce the baseline signal. We have synthesizeda proprietary water-soluble probenecid, which is supplied with theFluo-4 NW Calcium Assay Kits. This form of probenecid has theadvantages of being easy to dissolve in buffer and safer to use thanthe free acid, which requires caustic 1 M NaOH to dissolve. TheFluo-4 NW Calcium Assay Kits are designed for microplates andHTS, and the assay can be performed on adherent as well as nonadherentcells.

Fluo-4 AM is a fluorescent Ca+2 indicator that is widely usedfor in-cell measurement of agonist-stimulated and antagonist inhibitedcalcium signaling in high-throughput screening (HTS)applications. Its visible wavelength excitation (compatible withargon-ion laser sources), high sensitivity, and large fluorescenceincrease upon binding Ca2+ has made it the indicator of choicefor characterizing G-protein–coupled receptor (GPCR) pharmacologyand function. These properties have made fluo-4 AMattractive not only for microplate screening applications but formicroscopy and flow cytometry as well.

Fura-2, AM, cell permeant Invitrogen™

Fura-2, AM is a high affinity, intracellular calcium indicator that is ratiometric and UV light—excitable. This acetoxymethyl (AM) ester form is useful for noninvasive intracellular loading and is also available in 1 mg amounts (F-1201) and in a DMSO solution (F-1225). Cell-impermeant pentapotassium (F-1200) and pentasodium (F-6799) salt forms of the dye are available.

FluoZin™-2, AM, cell permeant Invitrogen™

The FluoZin™-1 and FluoZin™-2 indicators are designed to detect Zn2+ concentrations that are present in synaptic vesicles and released in response to electrical stimulation or excitotoxic agonists. Based on the N-(2-methoxyphenyl)iminodiacetate chelator, these indicators are designed for detection of Zn2+ in the 0-100 µM range with minimal interfering Ca2+ sensitivity. FluoZin™ indicators are offered in cell-permeant and cell-impermeant forms.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Fluorescent Zinc Indicators Specifications:
• Label (Ex/Em): FluoZin™-2 (~495/525 nm)
• Kd (Zn2+) (in buffer): ~2 µM
• Lyophilized product may be dissolved in DMSO for use
• Product is typically loaded into cells by adding the dissolved indicator to medium containing cells


Find Fluorescent Indicators for Zinc and Other Metal Ions
We offer a number of fluorescent indicators to determine polyvalent cation concentrations inside cells, to follow metal ion transport through ion channels, to make measurements in environmental samples, and more. Review Fluorescent Indicators for Zn2+ and Other Metal Ions-Section 19.7 in the Molecular Probes® Handbook for more information on these products.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

SNARF™-1 Carboxylic Acid, Acetate, Succinimidyl Ester - Special Packaging Invitrogen™

To permit simultaneous long-term tracing of mixed-cell populations using different fluorescent colors, we have developed a probe whose applications should be similar to those of CFDA SE (commonly called CFSE). Cells labeled with our SNARF-1 carboxylic acid, acetate, succinimidyl ester have orange-red fluorescence that can be easily distinguished from that of cells loaded with green-fluorescent tracers such as CFDA SE.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Rhod-2, AM, cell permeant Invitrogen™

Labeled calcium indicators are molecules that exhibit an increase in fluorescence upon binding Ca2+. They have uses in many calcium signaling investigations, including measuring Ca2+ in cells and tissues that have high levels of autofluorescence and also for detecting Ca2+ release generated by photoreceptors and photoactivatable chelators. Cells may be loaded with the AM ester forms of these calcium indicators by adding the dissolved indicator directly to dishes containing cultured cells. The fluorescence signal from these cells is generally measured using fluorescence microscopy.

Calcium Indicator (AM Ester) Specifications:
• Label (Ex/Em of Ca2+–bound form): Rhod-2 (552/581 nm)
• Fluorescence intensity increase upon binding Ca2+: >100 fold
• Kd for Ca2+ in the absence of Mg2+, in buffer: ~570 nM
• Exhibit fluorescence increase upon binding Ca2+ with little shift in wavelength


Using TPEN to Control Heavy Metal Cations
In addition, BAPTA-based indicators such as these bind various heavy metal cations (e.g., Mn2+, Zn2+, Pb2+) with substantially higher affinity than Ca2+. Perturbations to calcium measurements caused by presence of these ions can be controlled using the heavy metal-selective chelator TPEN.

More Choices for Fluorescent Calcium Indicators
We offer a large selection of Molecular Probes® calcium indicators for use in various experimental scenarios, for example dextran versions for reduced leakage and compartmentalization and BAPTA conjugates for detecting high-amplitude calcium transients. For more information, review Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3 in the Molecular Probes® Handbook.

For UV-excitable Ca2+ indicators, protein-based Ca2+ indicators, conjugates of Ca2+ indicators, and for fluorescence-based indicators of other metal ions (i.e., Mg2+, Zn2+) review Indicators for Ca2+, Mg2+, Zn2+ and Other Metal Ions—Chapter 19 in the Molecular Probes® Handbook.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

Carboxy-H2DFFDA Invitrogen™

H2DFFDA is a chemically reduced, acetylated form of fluorescein used as an indicator for reactive oxygen species (ROS) in cells. This nonfluorescent molecule is readily converted to a green-fluorescent form when the acetate groups are removed by intracellular esterases and oxidation (by the activity of ROS) occurs within the cell. This fluorinated analog exhibits improved photostability compared to the chlorinated fluorescein derivatives (DCF, DCFDA).

ROS Indicator Specifications:
• Ex/Em: ~492–495/517–527 nm
• Product is air sensitive and should be stored under dry argon or nitrogen
• Product may be dissolved in DMSO, DMF, or ethanol for use
• Indicator is cell permeant (cell loading protocols are available in the literature)
• Fluorescence can be monitored using a flow cytometer, fluorometer, microplate reader, or fluorescence microscope, using excitation sources and filters appropriate for fluorescein


Find More ROS Indicators
We offer an assortment of Molecular Probes® products for the generation of reactive oxygen species (ROS), including singlet oxygen, superoxide, hydroxyl radical and various peroxide and hydroperoxides, as well as for their fluorometric detection in solution. Review Generating and Detecting Reactive Oxygen Species—Section 18.2 in the Molecular Probes® Handbook for more information on these products.

For Research Use. Not for human or animal therapeutic or diagnostic use.

Coelenterazine h Invitrogen™

Coelenterazine h is one of several synthetic coelenterazine analogs that confer different Ca2+ affinities and spectral properties on the aequorin complex. Like native coelenterazine, these five novel derivatives can be used to reconstitute the aequorin complex both in vivo and in vitro.

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RedoxSensor™ Red CC-1 - Special Packaging Invitrogen™

RedoxSensor Red CC-1 is a unique probe whose fluorescence localization appears to be based on a cell's cytosolic redox potential. Upon passively entering live cells, the stain is either oxidized in the cytosol to a red-fluorescent product (excitation/emission maxima ~540/600 nm), which then accumulates in mitochondria, or the probe is transported to lysosomes, where it is subsequently oxidized. The differential distribution of the oxidized product appears to depend on the redox potential of the cytosol.

Newport Green™ DCF Diacetate, cell permeant Invitrogen™

The Newport Green™ DCF indicator has moderate zinc-binding affinity (Kd for Zn2+ ~1 µM) but is essentially insensitive to Ca2+ (Kd for Ca2+ >100 µM), making this a valuable probe for detecting Zn2+ influx into neurons through voltage- or glutamate-gated channels. When used alongside dyes with dual Ca2+ / Zn2+ sensitivity such as fura-2 and mag-fura-2, Newport Green™ DCF provides confirmation that changes in Zn2+ levels, and not Ca2+ or Mg2+, are being detected. The response of Newport Green™ DCF to transition metals, including Zn, Mn, Fe, Co, Cu(I), Cu(II), Ni and Cd, has been characterized.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Newport Green™ PDX has a higher Zn2+ dissociation constant (Kd for Zn2+ ~30 µM) and a larger Zn2+-free to Zn2+-saturated fluorescence intensity increase than the Newport Green™ DCF indicators.

Fluorescent Zinc Indicators Specifications:
• Label (Ex/Em): Newport Green™ DCF (~505/535 nm)
• Kd (Zn2+) (in buffer): ~1 µM
• Lyophilized product may be dissolved in DMSO for use
• Product is typically loaded into cells by adding the dissolved indicator to medium containing cells


Find Fluorescent Indicators for Zinc and Other Metal Ions
We offer a number of fluorescent indicators to determine polyvalent cation concentrations inside cells, to follow metal ion transport through ion channels, to make measurements in environmental samples, and more. Review Fluorescent Indicators for Zn2+ and Other Metal Ions—Section 19.7 in the Molecular Probes® Handbook for more information on these products.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

Calcium Green™-1, Hexapotassium Salt, cell impermeant Invitrogen™

The cell-impermeant dye, Calcium Green-1, is a visible light—excitable Ca2+ indicator. Although Calcium Green-1 is structurally similar to fluo-3, it is more fluorescent at low calcium concentrations, facilitating the determination of baseline Ca2+ levels and increasing the visibility of resting cells.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

FluoZin™-3, Tetrapotassium Salt, cell impermeant Invitrogen™

The FluoZin™-3 indicator is a Zn2+-selective indicator with a structure that resembles fluo-4. FluoZin™-3 exhibits high Zn2+-binding affinity that is unperturbed by Ca2+ concentrations up to at least 1 µM. In addition, FluoZin™-3 exhibits a >50-fold increase in fluorescence in response to saturating levels of Zn2+. Although imaging applications of FluoZin™-3 are predominant, cell-based microplate assays and flow cytometry protocols have also been developed. FluoZin™-3 indicator is available in a cell-permeant and a cell-impermeant form.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Fluorescent Zinc Indicators Specifications:
• Label (Ex/Em): FluoZin™-3 (~494/516 nm)
• Kd (Zn2+) (in buffer): ~15 nM
• Lyophilized product may be dissolved in distilled water or aqueous buffer for use
• Product is typically loaded into cellsusing microinjection or diffusion from patch pipette


Find Fluorescent Indicators for Zinc and Other Metal Ions
We offer a number of fluorescent indicators to determine polyvalent cation concentrations inside cells, to follow metal ion transport through ion channels, to make measurements in environmental samples, and more. Review Fluorescent Indicators for Zn2+ and Other Metal Ions—Section 19.7 in the Molecular Probes® Handbook for more information on these products.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

Oregon Green™ 488 BAPTA-1 dextran, Potassium Salt, 10,000 MW, Anionic Invitrogen™

Labeled calcium indicators are molecules that exhibit an increase in fluorescence upon binding Ca2+. They have uses in many calcium signaling investigations, including measuring intracellular Ca2+, following Ca2+ influx and release, and multiphoton excitation imaging of Ca2+ in living tissues. Cells may be physically loaded with the cell-impermeant salt forms of these dextran-conjugated indicators using patch pipette, microinjection, or our Influx pinocyte-loading reagent. The fluorescence signal from these cells is measured using fluorescence microscopy. The dextran forms of our calcium indicators show a dramatic reduction in both leakage and compartmentalization compared to the AM ester forms.

Learn more about ion indicators including calcium, potassium, pH, and membrane potential indicators ›

Calcium Indicator (Cell-Impermeant Salts, Dextran Conjugates) Specifications:
• Label (Ex/Em): Oregon Green® 488 BAPTA-1 (494/523 nm)
• Fluorescence intensity increase upon binding Ca2+: ~14 fold
• Dextran size: 10,000 MW
• Exhibit fluorescence increase upon binding Ca2+ with little shift in wavelength


Spectral Characteristics of Molecular Probes® Calcium Indicators
These probes are excited by visible light, and because the energy required for excitation is low, the potential for cellular photodamage is reduced. Commonly used laser-based instruments (i.e., confocal laser scanning microscopes) are able to efficiently excite these indicators, and their emissions are in regions of the spectrum where cellular autofluorescence and scattering backgrounds are often less of a problem.

More Choices for Fluorescent Calcium Indicators
We offer a large selection of Molecular Probes® calcium indicators for use in various experimental scenarios, for example dextran versions for reduced leakage and compartmentalization and BAPTA conjugates for detecting high-amplitude calcium transients. For more information, review Fluorescent Ca2+ Indicators Excited with Visible Light—Section 19.3 in the Molecular Probes® Handbook.

For UV-excitable Ca2+ indicators, protein-based Ca2+ indicators, conjugates of Ca2+ indicators, and for fluorescence-based indicators of other metal ions (i.e., Mg2+, Zn2+) review Indicators for Ca2+, Mg2+, Zn2+ and Other Metal Ions—Chapter 19 in the Molecular Probes® Handbook.

For Research Use Only. Not intended for animal or human therapeutic or diagnostic use.
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