Calcium Indicators

Cell-based calcium flux assays are widely used in high throughput screening (HTS) to determine agonist-stimulated and antagonist-inhibited signaling through G protein-coupled receptors (GPCRs), a large family of integral membrane proteins and an important target class in drug discovery. Accurate measurements of intracellular calcium concentration and mobilization allows for a more comprehensive understanding of calcium regulated signaling pathways, cellular functions and pathological processes.

AAT Bioquest has developed the largest collection of calcium indicators, including Fluo-8®, Cal-520®, and Calbryte™ calcium indicators, as well as, calcium flux assays to track calcium mobilization with intense fluorescent signals and in a variety of wavelength options ranging from ultraviolet to infrared.

Quantifying Cytosolic Calcium

Calcium is a ubiquitous messenger impacting a number of signal transduction pathways including calcium-induced changes in protein confirmation, the regulation of cytosolic and organelle calcium levels, the highly localized nature of calcium-mediated signal transduction and its specific roles in excitability, exocytosis, motility, apoptosis, and transcription. These pathways regulate many key cellular processes including neurotransmission, cell proliferation, and muscle contraction. Under normal conditions with respect to the extracellular fluid, the resting cytoplasmic concentration of calcium is relatively low, at or below 100 nM. Calcium signaling is activated either through the release of calcium ions from intracellular stores, or by an influx of extracellular calcium through plasma membrane ion channels. Stimulated cells can increase cytoplasmic calcium concentration up to 500 to 1000 nM.

Fluorescent AM Ester Derivatives for Live Cell Calcium Imaging

Fluorescent indicators that show spectral responses upon binding calcium have enabled researchers to investigate changes in intracellular free calcium concentrations by using fluorescence microscopy, flow cytometry, fluorescence spectroscopy and fluorescence microplate readers. To facilitate detecting intracellular calcium mobilization and promote passive diffusion, acetoxymethyl ester (AM ester) functional groups are attached to the core structure of calcium indicators. This increases the indicator’s hydrophobicity allowing it to easily penetrate intact plasma membranes, and enhances indicator sensitivity by minimizing non-specific background fluorescence because AM ester conjugated indicators are essentially non-fluorescent and inactive.

Activity is initiated once the probe enters a live cell and only after intracellular esterases remove the AM ester functional groups. Once activated, probes detect calcium through chelation and respond by generating a fluorescence signal relative to the concentration of calcium. Indicators such as Fluo-8®, AM (Cat No. 21080), Cal-520®, AM (Cat No. 21131) and Calbryte™ 520, AM (Cat No. 20653) have been extensively used in calcium imaging, calcium flux assays and cell-based high throughput screening (HTS) assays for drug discovery. Calcium indicators are compatible with use in flow cytometry, fluorescence microscopy, and the fluorescence microplate platform. Besides offering fluorescent and luminescent calcium indicators, we also provide several non-fluorescent calcium signaling molecules and chelators for measuring and manipulating intracellular and extracellular calcium.

 

Single-Wavelength Calcium Indicators

Single-wavelength calcium indicators are widely used to monitor calcium mobilization, image the spatial dynamics of calcium signaling, and in HTS cell-based pharmacological screening of agonist-stimulated and antagonist-inhibited signaling through GPCRs. These indicators exhibit significant calcium-dependent changes in fluorescence intensity at saturating calcium levels without shifting either their absorbance or emission wavelengths. We’ve developed a variety of novel calcium indicators, including the Fluo-8® series, the Cal-520® series and the Calbryte™ series, designed to trace calcium mobilization with the brightest fluorescent signals and a range of wavelength and affinity options to satisfy many applications.

Key features of single-wavelength calcium indicators

  • Minimal background fluorescence at resting calcium levels
  • Improved signal-to-background ratios
  • Greatly enhanced cellular retention
  • Cell-permeant formats for live cell calcium analysis (compatible with imaging, flow cytometry and microplate assays, such as HTS)
  • Cell-impermeant formats for loading by microinjection, patch pipette, or pinocytic loading
  • Ultraviolet (UV), violet and visible light-excitable formats
  • Low-, medium- and high-affinity formats provides a sensitivity range to satisfy many applications
Figure 1. ATP response measured in CHO-K1 cells. 100 µL of 10 µg/ml Calbryte™ 520 AM (Cat No. 20653) in HH Buffer with probenecid or 10 µg/ml Fluo-4, AM (Cat No. 20550) in HH Buffer with probenecid was added and incubated for 45 min at 37°C. Dye loading solution was then removed and replaced with 200 µL HH Buffer/well. ATP (50 µL/well) was added to achieve the final indicated concentration of 10 µM and then imaged with microscope FITC channel (Keyence).

Table 1. Green Fluorescent Calcium Indicators for Intracellular Calcium Detection

Dye Ex/Em (nm) Filter Set Kd¹ Φ² FCa/FFree³ Relative Brightness Signal/Noise Unit Size Cat No.
Calbryte™ 520, AM 492/514 FITC 1.2 µM 0.75 ∼300 fold ***** ***** 10 x 50 µg 20651
Cal-520®, AM 492/514 FITC 320 nM 0.75 ∼100 fold *** *** 10 x 50 µg 21130
Fluo-8®, AM 494/515 FITC 389 nM 0.16 ∼200 fold *** *** 10 x 50 µg 21082
Fluo-4, AM 492/527 FITC 345 nM 0.16 ∼100 fold ** ** 10 x 50 µg 20551
Fluo-3, AM 506/515 FITC 390 nM 0.15 ∼100 fold * * 20 x 50 µg 21013
  1. Kd = Calcium dissociation constant.
  2. Φ = fluorescence quantum yield in the presence of 5 mM calcium citrate.
  3. FCa/FFree = Increase in fluorescence intensity of calcium bound indicator relative to its calcium free indicator form.

 

Table 2. Long Wavelength Rhod Calcium Indicators for Intracellular Calcium Detection

Dye Ex/Em (nm) Filter Set Kd¹ Unit Size Cat No.
Rhod-2, AM 552/576 TRITC 570 nM 20 x 50 µg 21064
Rhod-4, AM 521/549 TRITC 451 nM 10 x 50 µg 21122
Rhod-5N, AM 557/579 TRITC 300 µM 1 mg 21070
Rhod-FF, AM 552/576 TRITC 19 µM 10 x 50 µg 21078
  1. Kd = Calcium dissociation constant.

 

Ratiometric Calcium Indicators

In comparison to single-wavelength indicators, ratiometric (or dual-wavelength) indicators possess unique spectral properties which are triggered in response to binding calcium. When binding to calcium, ratiometric indicators undergo a shift in either their optimum absorbance or emission wavelength intensities. For example, dual-excitation calcium indicators Fura-2, AM and Fura-8™, AM exhibit two peak excitation wavelengths when either bound or free of calcium. An increase in calcium concentration initiates an increase and decrease in the fluorescence emission intensities of the dual-excitation indicator when excited at the calcium-bound and calcium-free peak excitation wavelengths, respectively.

Key features of ratiometric calcium indicators

  • Ratiometric determination produces accurate measurement of intracellular calcium concentrations
  • Minimizes effects of uneven dye loading, dye leakage, photobleaching and varying cell thickness (common in mixed populations)
  • Delivers more robust and reproducible results
  • Indicators available in dual-excitation, dual-emission or dual-excitation and dual-emission formats
  • Available as membrane-permeant AM esters (compatible with imaging, flow cytometry and microplate assays, such as HTS)
  • Available as membrane-impermeant salt derivatives for loading by microinjection, patch pipette, or pinocytic loading
Figure 2. ATP Dose response in CHO-K1 cells measured with Fura-2 AM (Cat No. 21023) and Fura-8™ AM (Cat No. 21056). CHO-K1 cells were seeded overnight at 40,000 cells/100 µL/well in a black wall/clear bottom 96-well plate and then incubated with either Fura-2 AM or Fura-8 AM calcium assay dye-loading solution for 1 hour. ATP Dose was added by Flexstation.

Table 3. Dual-excitation ratiometric calcium indicators for live cell calcium imaging.

Dye Ex/Em (zero calcium) Ex/Em (high calcium) Filter Set Kd¹ Unit Size Cat No.
Fura-2, AM *UltraPure Grade* *CAS 108964-32-5* 340/510 380/510 Fura 2 145 nM 1 mg 21021
Fura-2, AM *UltraPure Grade* *CAS 108964-32-5* 340/510 380/510 Fura 2 145 nM 20×50 µg 21023
Fura-2, AM *CAS 108964-32-5* 340/510 380/510 Fura 2 145 nM 1 mg 21020
Fura-2, AM *CAS 108964-32-5* 340/510 380/510 Fura 2 145 nM 50 mg 21022
Fura-2, pentapotassium salt *CAS 113694-64-7* 340/510 380/510 Fura 2 145 nM 1 mg 21025
Fura-2, pentasodium salt 340/510 380/510 Fura 2 145 nM 1 mg 21026
Fura-FF, AM *CAS 348079-12-9* 340/510 380/510 Fura 2 5.5 µM 10×50 µg 21027
Fura-FF, pentapotassium salt *CAS 192140-58-2* 340/510 380/510 Fura 2 5.5 µM 10×50 µg 21028
Fura-FF, pentapotassium salt *CAS 192140-58-2* 340/510 380/510 Fura 2 5.5 µM 1 mg 21029
Fura-8™, AM 355/525 415/525 Fura 2 260 nM 10×50 µg 21056
  1. Calcium dissociation constant.

 

Table 4. Dual-emission ratiometric calcium indicators for live cell calcium imaging.

Dye Ex/Em (zero calcium) Ex/Em (high calcium) Filter Set Kd¹ Unit Size Cat No.
Indo-1, AM *CAS 112926-02-0* 355/475 355/400 Indo-1 230 nM 1 mg 21030
Indo-1, AM *CAS 112926-02-0* 355/475 355/400 Indo-1 230 nM 50 mg 21033
Indo-1, AM *UltraPure Grade* *CAS 112926-02-0* 355/475 355/400 Indo-1 230 nM 1 mg 21032
Indo-1, AM *UltraPure Grade* *CAS 112926-02-0* 355/475 355/400 Indo-1 230 nM 20×50 µg 21036
Indo-1, pentapotassium salt *CAS 132319-21-9* 355/475 355/400 Indo-1 230 nM 1 mg 21040
Indo-1, pentasodium salt 355/475 355/400 Indo-1 230 nM 1 mg 21044
Cal Red™ R525/650 AM 490/660 490/525 FITC 230 nM 10×50 µg 20591
Cal Red™ R525/650 AM 490/660 490/525 FITC 230 nM 1 mg 20590
Cal Red™ R525/650 potassium salt 490/660 490/525 FITC 230 nM 5×50 µg 20588
  1. Kd = Calcium dissociation constant.

 

Table 5. Dual-excitation and dual-emission ratiometric calcium indicators for live cell calcium imaging.

indicators for live cell calcium imaging.

Dye Ex/Em (zero calcium) Ex/Em (high calcium) Cutoff Kd¹ Unit Size Cat No.
Fura Red, AM *CAS 149732-62-7* 435/630 470/650 610, 630 400 nM 10×50 µg 21048
Fura Red, AM *CAS 149732-62-7* 435/630 470/650 610, 630 400 nM 1 mg 21046
Fura Red, potassium salt 435/630 470/650 610, 630 400 nM 10×50 µg 21047
Fura Red, potassium salt 435/630 470/650 610, 630 400 nM 1 mg 21045
  1. Kd = Calcium dissociation constant.

 

Calbryte™ Calcium Indicators

The Calbryte™ series is a family of the brightest and most robust calcium indicators developed to monitor intracellular calcium mobilization. It includes three novel calcium indicators, Calbryte™ 520, Calbryte™ 590 and Calbryte™ 630, which differ primarily in their absorbance and emission wavelengths. Calbryte™ probes emit fluorescence signals at significantly higher signal-to-background characteristics, and have greatly enhanced cellular retention. The Calbryte™ series has been optimized for use with fluorescence microscopes, fluorescence microplate readers and flow cytometers. They can also be used in high-throughput screening applications.

Key features of Calbryte™ calcium indicators

  • Calbryte™ probes are significantly brighter than any other calcium indicators under the same conditions
  • Greatly improved signal-to-background ratios
  • Enhanced intracellular retention, eliminates the use of probenecid
  • Fast and convenient cell loading in 45 to 60 minutes
  • Homogenous cytosolic localization
  • Red-shifted Calbryte™ 590 and Calbryte™ 630 can be used with GFP or other green-fluorescent dyes for multiplexing
  • Available as membrane-permeant AM esters (compatible with imaging, flow cytometry and microplate assays, such as HTS)
  • Available as membrane-impermeant salt derivatives for loading by microinjection, patch pipette, or pinocytic loading
  • Available as a reactive-dye for conjugation to a carrier

 

Proven performance, superior signal-to-noise ratio and intracellular retention properties

Figure 3. Probenecid-free ATP -induced calcium response measured in CHO-K1 cells. 100 µL of 10 µg/mL Calbryte-520 AM in HH Buffer or 10 µg/mL Fluo-4 in HH Buffer was added and incubated for 45 min at 37 °C. Dye loading solution was then removed and replaced with 200 µL HH Buffer/well. Carbachol (50 µL/well) was added by FlexStation 3 to achieve the final indicated concentrations.

Table 6. Calbryte™ calcium indicators for live cell calcium imaging.

Dye Ex (nm) Em (nm) Filter Set Kd¹ FCa/FFree² Unit Size Cat No.
Calbryte™ 520, AM 493 515 FITC 1.2 µM ∼300 fold 2×50 µg 20650
Calbryte™ 520, AM 493 515 FITC 1.2 µM ∼300 fold 10×50 µg 20651
Calbryte™ 520, AM 493 515 FITC 1.2 µM ∼300 fold 1 mg 20653
Calbryte™ 520, potassium salt 493 515 FITC 1.2 µM ∼300 fold 2×50 µg 20656
Calbryte™ 520, potassium salt 493 515 FITC 1.2 µM ∼300 fold 10×50 µg 20658
Calbryte™ 520L, AM 493 515 FITC 100 µM ∼300 fold 10×50 µg 20640
Calbryte™ 520L, potassium salt 493 515 FITC 100 µM ∼300 fold 10×50 µg 20642
Calbryte™-520XL azide 493 515 FITC 300 µM ∼300 fold 1 mg 20643
Calbryte™-520XL azide 493 515 FITC 300 µM ∼300 fold 10×50 µg 20645
Calbryte™ 590, AM 581 593 Cy3/TRITC 1.4 µM ∼300 fold 2×50 µg 20700
Calbryte™ 590, AM 581 593 Cy3/TRITC 1.4 µM ∼300 fold 10×50 µg 20701
Calbryte™ 590, AM 581 593 Cy3/TRITC 1.4 µM ∼300 fold 1 mg 20702
Calbryte™ 590, potassium salt 581 593 Cy3/TRITC 1.4 µM ∼300 fold 5×50 µg 20706
Calbryte™ 590, potassium salt 581 593 Cy3/TRITC 1.4 µM ∼300 fold 1 mg 20707
Calbryte™ 630, AM 607 624 Texas Red 1.2 µM ∼300 fold 2×50 µg 20720
Calbryte™ 630, AM 607 624 Texas Red 1.2 µM ∼300 fold 10×50 µg 20721
Calbryte™ 630, AM 607 624 Texas Red 1.2 µM ∼300 fold 1 mg 20722
Calbryte™ 630, potassium salt 607 624 Texas Red 1.2 µM ∼300 fold 5×50 µg 20727
  1. Kd = Calcium dissociation constant.
  2. Φ = fluorescence quantum yield in the presence of 5 mM calcium citrate.
  3. FCa/FFree = Increase in fluorescence intensity of calcium bound indicator relative to its calcium free indicator form.

 

Cal-520® Calcium Indicators

The Cal-520® calcium indicators series is the most comprehensive portfolio of fluorogenic calcium-sensitive dyes. It includes six unique indicators, Cal-500™, Cal-520®, Cal-590™, Cal-630™, Cal-670™ and Cal-770™, which differ primarily in their absorbance and emission wavelengths. Each of the indicators emit minimal fluorescence at resting levels of calcium, and increases its fluorescence intensity >100-fold at saturating calcium concentrations. The Cal-520&reg series of indicators are available as membrane-permeant AM esters, and membrane-impermeant salt derivatives and dextran conjugates.

Key features of Cal-520® calcium indicators

  • Higher signal-to-background ratios than Fluo-3, Fluo-4, Rhod-2 and Rhod-5
  • Enhanced intracellular retention
  • Convenient and efficient cell loading
  • Homogenous cytosolic localization
  • Red-shifted Cal-590™, Cal-630™, Cal-670™ and Cal-770™ can be used with GFP or other green-fluorescent dyes for multiplexing
  • Cal-770™ may be used for in vivo studies
  • Available as membrane-permeant AM esters (compatible with imaging, flow cytometry and microplate assays, such as HTS)
  • Available as membrane-impermeant salt derivatives for loading by microinjection, patch pipette, or pinocytic loading
  • Available as reactive-dyes for conjugation to a carrier
Figure 4. ATP-stimulated calcium responses of endogenous P2Y receptor in CHO-K1 cells incubated with Cal-520™ AM (red curve), or Fluo-4 AM (blue curve) respectively without probenecid. CHO-K1 cells were seeded overnight at 50,000 cells per 100 µL per well in a Costar black wall/clear bottom 96-well plate. 100 µL of 5 µM Fluo-4 AM or Cal 520™ AM in HHBS (with or without probenecid) was added into the cells, and the cells were incubated at 37 °C for 1 hour. ATP (50 µL/well) was added using FlexSation to achieve the final indicated concentrations.

Table 7. Cal-520® calcium indicators for live cell calcium imaging and multicolor calcium flux assays.

Dye Ex (nm) Em (nm) Filter Set Kd¹ Φ² FCa/FFree³ Unit Size Cat No.
Cal-500™, AM 388 482 DAPI 303 nM 0.48 ∼100 fold 10×50 µg 20412
Cal-500™, potassium salt 388 482 DAPI 303 nM 0.48 ∼100 fold 10×50 µg 20410
Cal-520®, AM 493 515 FITC 320 nM 0.75 ∼100 fold 10×50 µg 21130
Cal-520®, potassium salt 493 515 FITC 320 nM 0.75 ∼100 fold 10×50 µg 21140
Cal-590™ AM 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 5×50 µg 20510
Cal-590™ potassium salt 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 5×50 µg 20518
Cal-630™ AM 609 626 Texas Red 792 nM 0.37 ∼100 fold 5×50 µg 20530
Cal-630™, potassium salt 609 626 Texas Red 792 nM 0.37 ∼100 fold 5×50 µg 20538
Cal-670™, potassium salt 667 680 Cy5 853 nM N/D ∼100 fold 10×50 µg 20455
Cal-770™, potassium salt 758 783 Cy7 850 nM N/D ∼100 fold 10×50 µg 20460
Cal-520®, AM 493 515 FITC 320 nM 0.75 ∼100 fold 1 mg 21131
Cal-520FF™, AM 493 515 FITC 9.8 µM 0.75 ∼100 fold 10×50 µg 21143
Cal-520FF™, AM 493 515 FITC 9.8 µM 0.75 ∼100 fold 1 mg 21142
Cal-520N™, AM 493 515 FITC 90 µM 0.75 ∼100 fold 10×50 µg 21146
Cal-520®, potassium salt 493 515 FITC 320 nM 0.75 ∼100 fold 1 mg 21141
Cal-520®, sodium salt 493 515 FITC 320 nM 0.75 ∼100 fold 10×50 µg 21135
Cal-520®, sodium salt 493 515 FITC 320 nM 0.75 ∼100 fold 1 mg 21136
Cal-520FF™, potassium salt 493 515 FITC 9.8 µM 0.75 ∼100 fold 10×50 µg 21144
Cal-520N™, potassium salt 493 515 FITC 90 µM 0.75 ∼100 fold 10×50 µg 21147
Cal-520®-Dextran Conjugate *MW 3,000* 493 515 FITC 320 nM 0.75 ∼100 fold 1 mg 20600
Cal-520®-Dextran Conjugate *MW 10,000* 493 515 FITC 320 nM 0.75 ∼100 fold 5 mg 20601
Cal-520L®-Dextran Conjugate *MW 10,000* 493 515 FITC 0.75 ∼100 fold 1 mg 20602
Cal-520®-Biotin Conjugate 493 515 FITC 320 nM 0.75 ∼100 fold 5×50 µg 20605
Cal-520®-Biocytin Conjugate 493 515 FITC 320 nM 0.75 ∼100 fold 5×50 µg 20606
Cal-520® NHS Ester 493 515 FITC 320 nM 0.75 ∼100 fold 100 µg 20609
Cal-520® maleimide 493 515 FITC 320 nM 0.75 ∼100 fold 100 µg 20610
Cal-590™ AM 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 10×50 µg 20511
Cal-590™ AM 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 1 mg 20512
Cal-590™ potassium salt 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 1 mg 20519
Cal-590™ sodium salt 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 5×50 µg 20515
Cal-590™-Dextran Conjugate *MW 3,000* 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 1 mg 20508
Cal-590™-Dextran Conjugate *MW 10,000* 574 588 Cy3/TRITC 561 nM 0.62 ∼100 fold 1 mg 20509
Cal-630™ AM 609 626 Texas Red 792 nM 0.37 ∼100 fold 10×50 µg 20531
Cal-630™ AM 609 626 Texas Red 792 nM 0.37 ∼100 fold 1 mg 20532
Cal-630™, sodium salt 609 626 Texas Red 792 nM 0.37 ∼100 fold 5×50 µg 20535
Cal-630™-Dextran Conjugate *MW 10,000* 609 626 Texas Red 792 nM 0.37 ∼100 fold 1 mg 20546
Cal-670™-Dextran Conjugate *MW 3,000* 667 680 Cy5 853 nM N/D ∼100 fold 1 mg 20456
Cal-670™-Dextran Conjugate *MW 10,000* 667 680 Cy5 853 nM N/D ∼100 fold 1 mg 20457
Cal-770™-Dextran Conjugate *MW 3,000* 758 783 Cy7 853 nM N/D ∼100 fold 1 mg 20461
Cal-770™-Dextran Conjugate *MW 10,000* 758 783 Cy7 853 nM N/D ∼100 fold 1 mg 20462
  1. Kd = Calcium dissociation constant.
  2. Φ = fluorescence quantum yield in the presence of 5 mM calcium citrate.
  3. FCa/FFree = Increase in fluorescence intensity of calcium bound indicator relative to its calcium free indicator form.
  4. N/D = not determined.

 

Fluo 8® Calcium Indicators

Fluo-8® AM addresses one of the major limitations common to fluo-based dyes, namely, the harsh conditions required for cell loading. Traditional fluo-based dyes such as Fluo- 2 AM (Cat No. 20495), Fluo-3 AM (Cat No. 21013 and Fluo-4 AM (Cat No. 20550) need to be loaded and incubated with cells at 37°C for up to an hour before a reading can be taken. This not only subjects cells to harsh temperatures, but also requires users to spend time heating and cooling cell cultures. Additionally, it introduces incubation temperature as a possible confounding variable. Fluo-8® AM resolves all these problem by providing a robust calcium indicator that can be loaded into cells at room temperature. Fluo-8® AM is less temperature dependent than other fluo-based dyes, allowing for more consistent results under a wider range of experimental conditions. Furthermore, with an incubation time of as little as 20 minutes, Fluo-8® AM enables fast turnaround for improved productivity. The best part is that even with structural modifications and improvements, Fluo-8® AM’s spectral properties remains unchanged, maintaining the familiar spectra of Fluo-4 AM (ie. Ex/Em = 494/517nm).

Key features of Fluo 8® calcium indicators

  • Faster cell loading: Fluo 8® can be readily loaded into cells at room temperature. Fluo-3 AM and Fluo-4 AM require a loading temperature of 37°C
  • Brighter fluorescence: Fluo 8® is 2 times brighter than Fluo-4 AM, and 4 times brighter than Fluo-3 AM
  • Convenient: Fluo 8®’s identical spectra to those of Fluo-4 and Fluo-3 makes upgrading easy
Figure 5. Carbachol dose response measured in HEK-293 cells. Hek-293 cells were seeded overnight at 40,000 cells/100 µL/well in a Costar black wall/clear bottom 96-well plate. The cells were incubated with 100 µL of dye loading solution using Fluo-8® AM (Cat No. 21083) or Fluo-4 AM (Cat No. 20550) for 1 hour at room temperature. Carbachol (50 µL/well) was added by NOVOstar (BMG Labtech) to achieve the final indicated concentrations.

Table 8. Fluo-8® green fluorescent calcium indicators for live cell calcium imaging.

Indicator Ex (nm) Em (nm) Filter Set Kd¹ Φ² FCa/FFree³ Unit Size Cat No.
Fluo-8®, AM 495 516 FITC 389 nM 0.16 ∼200 fold 1 mg 21080
Fluo-8®, AM 495 516 FITC 389 nM 0.16 ∼200 fold 10×50 µg 21082
Fluo-8®, AM 495 516 FITC 389 nM 0.16 ∼200 fold 20×50 µg 21083
Fluo-8®, AM 495 516 FITC 389 nM 0.16 ∼200 fold 5×50 µg 21081
Fluo-8®H™, AM 495 516 FITC 232 nM 0.16 ∼200 fold 10×50 µg 21091
Fluo-8®H™, AM 495 516 FITC 232 nM 0.16 ∼200 fold 1 mg 21090
Fluo-8®L™, AM 495 516 FITC 232 nM 0.16 ∼200 fold 1 mg 21096
Fluo-8®L™, AM 495 516 FITC 1.9 µM 0.16 ∼200 fold 10×50 µg 21097
Fluo-8®FF™, AM 495 516 FITC 10 µM 0.16 ∼200 fold 10×50 µg 21104
Fluo-8®FF™, AM 495 516 FITC 10 µM 0.16 ∼200 fold 1 mg 21105
Fluo-8®, potassium salt 495 516 FITC 389 nM 0.16 ∼200 fold 1 mg 21087
Fluo-8®, potassium salt 495 516 FITC 389 nM 0.16 ∼200 fold 10×50 µg 21089
Fluo-8®, sodium salt 495 516 FITC 389 nM 0.16 ∼200 fold 1 mg 21086
Fluo-8®, sodium salt 495 516 FITC 389 nM 0.16 ∼200 fold 10×50 µg 21088
Fluo-8H™, sodium salt 495 516 FITC 232 nM 0.16 ∼200 fold 10×50 µg 21095
Fluo-8L™, sodium salt 495 516 FITC 232 nM 0.16 ∼200 fold 10×50 µg 21098
Fluo-8L™, sodium salt 495 516 FITC 232 nM 0.16 ∼200 fold 1 mg 21099
  1. Kd = Calcium dissociation constant.
  2. Φ = fluorescence quantum yield in the presence of 5 mM calcium citrate.
  3. FCa/FFree = Increase in fluorescence intensity of calcium bound indicator relative to its calcium free indicator form.

 

Fluo-3 and Fluo-4 Calcium Indicators

Fluo-3 is a calcium indicator first introduced in 1989 for use in flow cytometry and confocal laser-scanning microscopy. A fluorescein-like compound, Fluo-3 is effectively non-fluorescent in the absence of free Ca2+. Upon binding to calcium, however, Fluo-3 experiences a sharp increase in emission intensity at 525 nm. As an indicator, Fluo-3 has been essential in the study of cell signaling pathways, myocytes and the activation of neurotransmitters.

Fluo-4 builds upon Fluo-3’s core structure, but modifying it for increased fluorescence signal strength. The modification in chemical structure causes a blue-shift in Fluo-4’s excitation maximum, from 506nm (of Fluo-3) to 494nm. Practically speaking, this 12 nm shift moves Fluo-4’s excitation maximum closer to the wavelength of a standard argon laser (ie. 488nm). This results in better excitation and thus, a fluorescent signal that is significantly brighter and more sensitive to changes in calcium concentration.

Fluo 3, AM

Fluo 4, AM

Fluo 8, AM

Figure 6. U2OS cells were seeded overnight at 40,000 cells/100 µL/well in a 96-well black wall/clear bottom costar plate. The growth medium was removed, and the cells were incubated with 100 µL of Fluo-3 AM, Fluo-4 AM and Fluo-8® AM in HHBS at a concentration of 4 µM in a 37 °C, 5% CO2 incubator for 1 hour. The cells were washed twice with 200 µL HHBS, then imaged with a fluorescence microscope (Olympus IX71) using FITC channel.

 

Table 9. Fluo-3, Fluo-4 and Fluo-5 green fluorescent calcium indicators for live cell calcium imaging.

Indicator Ex (nm) Em (nm) Filter Set Kd¹ Φ² FCa/FFree³ Unit Size Cat No.
Fluo-3, AM *UltraPure grade* *CAS 121714-22-5* 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21011
Fluo-3, AM *Bulk package* *CAS 121714-22-5* 507 516 FITC 390 nM 0.15 ∼100 fold 50 mg 21012
Fluo-3, AM *CAS 121714-22-5* 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21010
Fluo-3, AM *UltraPure grade* *CAS 121714-22-5* 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21013
Fluo-3, pentapotassium salt 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21017
Fluo-3, pentaammonium salt 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21018
Fluo-3, pentasodium salt 507 516 FITC 390 nM 0.15 ∼100 fold 1 mg 21016
Fluo-3FF, pentapotassium salt 507 516 FITC 100 µM 0.15 ∼100 fold 1 mg 21019
Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 495 528 FITC 345 nM 0.16 ∼100 fold 1 mg 20550
Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 495 528 FITC 345 nM 0.16 ∼100 fold 10×50 µg 20551
Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 495 528 FITC 345 nM 0.16 ∼100 fold 5×50 µg 20552
Fluo-4, Pentapotassium Salt 495 528 FITC 345 nM 0.16 ∼100 fold 1 mg 20555
Fluo-4, Pentapotassium Salt 495 528 FITC 345 nM 0.16 ∼100 fold 1 mg 20556
Fluo-5F, AM 494 516 FITC 2.3 µM 0.16 ∼100 fold 10×50 µg 20560
Fluo-5N, AM 494 516 FITC 90 µM 0.16 ∼100 fold 10×50 µg 20566
Fluo-5F, pentapotassium salt 494 516 FITC 2.3 µM 0.16 ∼100 fold 500 µg 20562
Fluo-5N, pentapotassium salt 494 516 FITC 90 µM 0.16 ∼100 fold 500 µg 20567
  1. Kd = Calcium dissociation constant.
  2. Φ = fluorescence quantum yield in the presence of 5 mM calcium citrate.
  3. FCa/FFree = Increase in fluorescence intensity of calcium bound indicator relative to its calcium free indicator form.

 

Calcium Assays for Screening GPCR and Calcium Channel Targets

Screen Quest™ calcium flux assays are the preferred method in cell-based high throughput screening (HTS) to determine agonist-stimulated and antagonist-inhibited signaling through G protein coupled receptors (GPCRs). To date approximately one third of drugs available on the market are designed to target GPCRs. The Screen Quest™ Calcium Assay offers a convenient no-wash, homogeneous fluorescence-based assay for monitoring GPCRs and calcium channels, and to detect intracellular calcium mobilization across a broad spectrum of biological targets. The assay can be performed in a convenient 96-well or 384-well microtiter-plate format and can be easily adapted for automation. Screen Quest™ Calcium Assays are optimized and validated for the following instruments: FDSS®, FLIPR®, ViewLux™, NOVOStar, ArrayScan™, FlexStation® and IN Cell Analyzer.

Screen Quest™ Calcium Assays Key Features

  • Optimized protocols validated for a broad range of microplate readers
  • Superior signal intensity (high S/B ratios) and well-to-well uniformity
  • Large assay window for assaying challenging cell lines and receptors
  • High performance calcium flux assays for 1536 well-plates
Figure 7. Comparison of fluorescent signal response of endogenous P2Y receptor to ATP in CHO-K1 cells using Screen Quest™ Calbryte™ 520 Calcium Assay Kit, FLIPR® Calcium 4 Assay (Molecular Devices), and Fluo-4 Direct™ Calcium Assay (Molecular Probes®). CHO-K1 cells were seeded overnight at 50,000 cells/100 µL/well in a 96-well black wall/clear bottom costar plate. Calcium flux response was measured with all three assays, respectively. ATP (50 µL/well) was added by FlexStation 3 to achieve the final indicated concentrations.

Table 10. Screen Quest™ Calcium Assays for screening GPCR and calcium channel targets.

Calcium Assay Ex (nm) Em (nm) Cutoff (nm) Unit Size Cat No.
Screen Quest™ Fluo-4 No Wash Calcium Assay Kit 490 525 515 10 plates 36325
Screen Quest™ Fluo-4 No Wash Calcium Assay Kit 490 525 515 100 plates 36326
Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 510 1 plates 36314
Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 510 10 plates 36315
Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 510 100 plates 36316
Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 510 100 plates 36316
Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 510 1 plates 36307
Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 510 10 plates 36308
Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 510 100 plates 36309
Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 515 1 plates 36317
Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 515 10 plates 36318
Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 515 100 plates 36319
Screen Quest™ Fura-2 No Wash Calcium Assay Kit 340, 380 510 470 10 plates 36320
Screen Quest™ Fura-2 No Wash Calcium Assay Kit 340, 380 510 470 100 plates 36321
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 540 590 570 1 plates 36333
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 540 590 570 10 plates 36334
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 540 590 570 100 plates 36335
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 540 590 570 1 plates 36330
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 540 590 570 10 plates 36331
Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 540 590 570 100 plates 36332
Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 540 590 570 1 plates 36200
Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 540 590 570 10 plates 36201
Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 540 590 570 100 plates 36202

GPCR Cell Lines for Drug Discovery and High Throughput Screening

Screen Quest™ cell lines are a series of cells that have been successfully used in drug discovery and screening environments for studying G-protein-coupled receptors (GPCR) that do not conventionally couple through intracellular calcium. It has been effectively used with the FLIPR, FDSS Systems in conjunction with non-Gq coupled members of many receptors such as chemokine, serotonin, glutamate, dopamine, opioid, vasopressin and α- and ß- adrenergic receptor families. Over 60% of the known GPCR signal through pathways other than Gq which lead to an increase in intracellular calcium, and as genomics reveals more G-protein-coupled receptor targets this trend continues to increase. Screen Quest™ cell lines are used for investigating GPCR that do not conventionally couple through intracellular calcium.

Screen Quest™ cell lines are based on a series of G-protein chimeras, including the promiscuous G-protein, Gα16. The chimeras consist of the alpha subunit of a Gq-protein complex whose 5 carboxy-terminal amino acids have been replaced with those from one of the other G-proteins (either Gαs, Gαi, Gαo, or Gαz). These amino acids are responsible for the coupling of the receptor to its G-protein. Co-expression of these chimeras with specific non-Gq-coupled receptors which normally act through the cAMP pathway may result in the generation of an intracellular calcium signal upon receptor stimulation.

 

Table 11. Stable GPCR cell lines for drug discovery and high-throughput screening assays.

Product name Unit Size Cat No.
Screen Quest™ HEK-CNGC-Amylin 3 Receptor Cells Each 38000
Screen Quest™ HEK-CNGC-Cannabinoid Receptor 1 Cells Each 38001
Screen Quest™ CHO-Ga16- Chemokine (C-C) Receptor 2B Cells Each 38002
Screen Quest™ HEK-CNGC-Chemokine (C-X-C motif) Receptor 4 Cells Each 38003
Screen Quest™ CHO-Ga16 Chimera Cell line Each 38105
Screen Quest™ CHO-Gqi Chimera Cell line Each 38101
Screen Quest™ CHO-Gqo Chimera Cell line Each 38102
Screen Quest™ CHO-Gqs Chimera Cell line Each 38104
Screen Quest™ CHO-Gqz Chimera Cell line Each 38103
Screen Quest™ HEK-CNGC-Dopamine Receptor 1 (DRD1) Cells Each 38004
Screen Quest™ HEK-CNGC-Glucagon-like Receptor 1 (GLP1R) Cells Each 38005
Screen Quest™ Human Nociceptin Receptor Ga16 coupled CHO Cells (NOP-Ga16) Each 38100
Screen Quest™ Live Cell cAMP Assay Service Pack Each 36382
Screen Quest™ HEK-CNGC-Opiate Receptor-like 1 (ORL1) Cells Each 38006

Product ordering information

 

Table 12. Ordering Info for Non-Fluorescent Calcium Detection Reagents Products

Cat# Product Name Unit Size
20050 Pluronic® F-127 *Cell culture tested * 10 g
20052 Pluronic® F-127 *20% solution in DMSO* 10 mL
20053 Pluronic® F-127 *10% solution in water* 10 mL
20060 Probenecid *Cell culture tested* *CAS 57-66-9* 10×72 mg
20061 ReadiUse™ probenecid, sodium salt *Water-soluble* 10×77 mg
20062 ReadiUse™ probenecid *25 mM stabilized aqueous solution* 10×10 mL
20305 Amplite™ Fluorimetric cADP-Ribose Assay Kit 100 tests
20997 NAADP-AM 2X50 ug
20998 NAADP-AM 250 ug
20999 NAADP [Nicotinic acid adenine dinucleotide phosphate sodium salt] *CAS 5502-96-5* 1 mg
21000 NAADP-AM 1 mg
21001 BAPTA, AM *CAS 126150-97-8* 25 mg
21002 BAPTA, AM *UltraPure Grade* *CAS 126150-97-8* 25 mg
21003 BAPTA, tetrapotassium salt *CAS 73630-08-7* 100 mg
21004 BAPTA, tetrasodium salt *CAS 126824-24-6* 100 mg
21005 EGTA AM *CAS 99590-86-0* 10 mg
21007 EGTA tetrasodium salt *CAS 13368-13-3* 1 g

Table 13. Ordering Info for Traditional Single Wavelength Calcium Indicators (Price Table) Products

Cat# Product Name Ex Em Unit Size
20451 Rhod-2 dextran conjugate *Low affinity with MW 10,000* 557 579 1 mg
20500 Cal Green™ 1, hexapotassium salt 506 531 10×50 ug
20501 Cal Green™ 1, AM [Equivalent to Calcium Green-1, AM] 506 531 10×50 ug
20502 Cal Green™ 1, AM [Equivalent to Calcium Green-1, AM] 506 531 1 mg
20506 OG488 BAPTA-1, hexapotassium salt [equivalent to Oregon Green® 488 BAPTA-1, hexapotassium salt] *Cell impermeant* 494 523 500 ug
20507 OG488 BAPTA-1, AM [equivalent to Oregon Green® 488 BAPTA-1, AM] *Cell permeant* 494 523 10×50 ug
21060 Rhod-2, AM *CAS#: 145037-81-6* 549 578 1 mg
21062 Rhod-2, AM *UltraPure Grade* *CAS#: 145037-81-6* 549 578 1 mg
21063 Rhod-2, AM *UltraPure Grade* *CAS#: 145037-81-6* 549 578 50 mg
21064 Rhod-2, AM *UltraPure Grade* *CAS#: 145037-81-6* 549 578 20×50 ug
21067 Rhod-2, tripotassium salt 549 578 1 mg
21068 Rhod-2, trisodium salt 549 578 1 mg
21070 Rhod-5N, AM 551 577 1 mg
21072 Rhod-5N, tripotassium salt 551 577 1 mg
21075 Rhod-FF, tripotassium salt 549 578 1 mg
21076 Rhod-FF, tripotassium salt 549 578 10×50 ug
21077 Rhod-FF, AM 549 578 1 mg
21078 Rhod-FF, AM 549 578 10×50 ug
21118 Rhod-4™, sodium salt 524 551 1 mg
21119 Rhod-4™, potassium salt 524 551 1 mg
21120 Rhod-4™, AM 524 551 1 mg
21121 Rhod-4™, AM 524 551 5×50 ug
21122 Rhod-4™, AM 524 551 10×50 ug
21123 Rhod-4™, AM 524 551 20×50 ug
21128 Rhod-4™, sodium salt 524 551 5×50 ug
21129 Rhod-4™, potassium salt 524 551 5×50 ug
36330 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 530 590 1 Plate
36331 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 530 590 10 Plates
36332 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit *Medium Removal* 530 590 100 Plates
36333 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 530 590 1 Plate
36334 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 530 590 10 Plates
36335 Screen Quest™ Rhod-4 No Wash Calcium Assay Kit 530 590 100 Plates

Table 14. Ordering Info for Ratiometric Calcium Indicators (Price Table) Products

Cat# Product Name Ex Em Unit Size
20588 Cal Red™ R525/650 potassium salt 492 650 5×50 ug
20590 Cal Red™ R525/650 AM 492 650 1 mg
20591 Cal Red™ R525/650 AM 492 650 10×50 ug
20620 Fura-8FF™, AM 354 525 10×50 ug
20621 Fura-8FF™, pentapotassium salt 354 415 10×50 ug
21020 Fura-2, AM *CAS 108964-32-5* 363 512 1 mg
21021 Fura-2, AM *UltraPure Grade* *CAS 108964-32-5* 363 512 1 mg
21022 Fura-2, AM *CAS 108964-32-5* 363 512 50 mg
21023 Fura-2, AM *UltraPure Grade* *CAS 108964-32-5* 363 512 20×50 ug
21025 Fura-2, pentapotassium salt *CAS 113694-64-7* 363 512 1 mg
21026 Fura-2, pentasodium salt 363 512 1 mg
21027 Fura-FF, AM [Fura-2FF, AM] *CAS 348079-12-9* 363 512 10×50 ug
21028 Fura-FF, pentapotassium salt [Fura-2FF, pentapotassium salt] *CAS 192140-58-2* 363 512 10×50 ug
21029 Fura-FF, pentapotassium salt [Fura-2FF, pentapotassium salt] *CAS 192140-58-2* 363 512 1 mg
21030 Indo-1, AM *CAS 112926-02-0* 346 475 1 mg
21032 Indo-1, AM *UltraPure Grade* *CAS 112926-02-0* 346 475 1 mg
21033 Indo-1, AM *CAS 112926-02-0* 346 475 50 mg
21036 Indo-1, AM *UltraPure Grade* *CAS 112926-02-0* 346 475 20×50 ug
21040 Indo-1, pentapotassium salt *CAS 132319-21-9* 346 475 1 mg
21044 Indo-1, pentasodium salt 346 475 1 mg
21045 Fura Red, potassium salt 458 597 1 mg
21046 Fura Red, AM *CAS 149732-62-7* 458 597 1 mg
21047 Fura Red, potassium salt 458 597 10×50 ug
21048 Fura Red, AM *CAS 149732-62-7* 458 597 10×50 ug
21050 Quin-2, AM *CAS 83104-85-2* 353 495 1 mg
21052 Quin-2, tetrapotassium salt *CAS 149022-19-5* 353 495 5 mg
21055 Fura-8™, AM 354 525 1 mg
21056 Fura-8™, AM 354 525 10×50 ug
21057 Fura-8™, pentapotassium salt 354 525 1 mg
21058 Fura-8™, pentasodium salt 354 525 1 mg
36320 Screen Quest™ Fura-2 No Wash Calcium Assay Kit 370 476 10 Plates
36321 Screen Quest™ Fura-2 No Wash Calcium Assay Kit 370 476 100 Plates

Table 15. Ordering Info for Calbryte Calcium Indicators (Price Table) Products

Cat# Product Name Ex Em Unit Size
20640 Calbryte™-520L AM 492 514 10×50 ug
20642 Calbryte™-520L, potassium salt 492 514 10X50 ug
20643 Calbryte™-520XL azide 492 514 1 mg
20645 Calbryte™-520XL, potassium salt 492 514 10×50 ug
20650 Calbryte™ 520 AM 492 514 2×50 ug
20651 Calbryte™ 520 AM 492 514 10×50 ug
20653 Calbryte™ 520 AM 492 514 1 mg
20656 Calbryte™ 520, potassium salt 492 514 2×50 ug
20658 Calbryte™ 520, potassium salt 492 514 10×50 ug
20700 Calbryte™ 590 AM 573 588 2×50 ug
20701 Calbryte™ 590 AM 573 588 10×50 ug
20702 Calbryte™ 590 AM 573 588 1 mg
20706 Calbryte™ 590, potassium salt 573 588 5×50 ug
20707 Calbryte™ 590, potassium salt 573 588 1 mg
20720 Calbryte™ 630 AM 608 626 2×50 ug
20721 Calbryte™ 630 AM 608 626 10×50 ug
20722 Calbryte™ 630 AM 608 626 1 mg
20727 Calbryte™ 630, potassium salt 608 626 5×50 ug
36200 Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 573 588 1 Plate
36201 Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 573 588 10 Plates
36202 Screen Quest™ Calbryte-590 Probenecid-Free and Wash-Free Calcium Assay Kit 573 588 100 Plates
36317 Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 1 Plate
36318 Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 10 Plates
36319 Screen Quest™ Calbryte-520 Probenecid-Free and Wash-Free Calcium Assay Kit 490 525 100 Plates

Table 16. Ordering Info for Cal520 Calcium Indicators (Price Table) Products

Cat# Product Name Ex Em Unit Size
20410 Cal-500™, potassium salt 390 500 10×50 ug
20412 Cal-500™ AM 390 500 10×50 ug
20455 Cal-670™, potassium salt 650 670 10×50 ug
20456 Cal-670™-Dextran Conjugate *MW 3,000* 650 675 1 mg
20457 Cal-670™-Dextran Conjugate *MW 10,000* 650 675 1 mg
20460 Cal-770™, potassium salt 750 775 10×50 ug
20461 Cal-770™-Dextran Conjugate *MW 3,000* 750 775 1 mg
20462 Cal-770™-Dextran Conjugate *MW 10,000* 750 775 1 mg
20508 Cal-590™-Dextran Conjugate *MW 3,000* 573 588 1 mg
20509 Cal-590™-Dextran Conjugate *MW 10,000* 573 588 1 mg
20510 Cal-590™ AM 573 588 5×50 ug
20511 Cal-590™ AM 573 588 10×50 ug
20512 Cal-590™ AM 573 588 1 mg
20515 Cal-590™, sodium salt 573 588 5×50 ug
20518 Cal-590™, potassium salt 573 588 5×50 ug
20519 Cal-590™, potassium salt 573 588 1 mg
20530 Cal-630™ AM 608 626 5×50 ug
20531 Cal-630™ AM 608 626 10×50 ug
20532 Cal-630™ AM 608 626 1 mg
20535 Cal-630™, sodium salt 608 626 5×50 ug
20538 Cal-630™, potassium salt 608 626 5×50 ug
20546 Cal-630™-Dextran Conjugate *MW 10,000* 608 626 1 mg
20600 Cal-520®-Dextran Conjugate *MW 3,000* 492 514 1 mg
20601 Cal-520®-Dextran Conjugate *MW 10,000* 492 514 5 mg
20602 Cal-520L®-Dextran Conjugate *MW 10,000* 1 mg
20605 Cal-520®-Biotin Conjugate 492 514 5×50 ug
20606 Cal-520®-Biocytin Conjugate 492 514 5×50 ug
20609 Cal-520® NHS Ester 492 514 100 ug
20610 Cal-520® maleimide 492 514 100 ug
21130 Cal-520®, AM 492 514 10×50 ug
21131 Cal-520®, AM 492 514 1 mg
21135 Cal-520®, sodium salt 492 514 10×50 ug
21136 Cal-520®, sodium salt 492 514 1 mg
21140 Cal-520®, potassium salt 492 514 10×50 ug
21141 Cal-520®, potassium salt 492 514 1 mg
21142 Cal-520FF™, AM 492 514 1 mg
21143 Cal-520FF™, AM 492 514 10×50 ug
21144 Cal-520FF™, potassium salt 492 514 10×50 ug
21146 Cal-520N™, AM 492 514 10×50 ug
21147 Cal-520N™, potassium salt 492 514 10×50 ug

Table 17. Ordering Info for Fluo Calcium Indicators (Price Table) Products

Cat# Product Name Ex Em Unit Size
20493 Fluo-2, potassium salt 494 517 10×50 ug
20494 Fluo-2, AM 494 517 10×50 ug
20495 Fluo-2, AM 494 517 1 mg
20550 Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 494 516 1 mg
20551 Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 494 516 10×50 ug
20552 Fluo-4 AM *Ultrapure Grade* *CAS 273221-67-3* 494 516 5×50 ug
20555 Fluo-4, Pentapotassium Salt 494 516 1 mg
20556 Fluo-4, Pentapotassium Salt 494 516 10×50 ug
20560 Fluo-5F, AM *Cell permeant* 494 516 10×50 ug
20562 Fluo-5F, pentapotassium Salt *Cell impermeant* 494 516 500 ug
20566 Fluo-5N, AM *Cell permeant* 494 516 10×50 ug
20567 Fluo-5N, pentapotassium Salt *Cell impermeant* 494 516 500 ug
21010 Fluo-3, AM *CAS 121714-22-5* 506 526 1 mg
21011 Fluo-3, AM *UltraPure grade* *CAS 121714-22-5* 506 526 1 mg
21012 Fluo-3, AM *Bulk package* *CAS 121714-22-5* 506 526 50 mg
21013 Fluo-3, AM *UltraPure grade* *CAS 121714-22-5* 506 526 20×50 ug
21016 Fluo-3, pentasodium salt 506 526 1 mg
21017 Fluo-3, pentapotassium salt 506 526 1 mg
21018 Fluo-3, pentaammonium salt 506 526 1 mg
21019 Fluo-3FF, pentapotassium salt 506 526 1 mg
21080 Fluo-8®, AM 494 517 1 mg
21081 Fluo-8®, AM 494 517 5×50 ug
21082 Fluo-8®, AM 494 517 10×50 ug
21083 Fluo-8®, AM 494 517 20×50 ug
21086 Fluo-8®, sodium salt 494 517 1 mg
21087 Fluo-8®, potassium salt 494 517 1 mg
21088 Fluo-8®, sodium salt 494 517 10×50 ug
21089 Fluo-8®, potassium salt 494 517 10×50 ug
21090 Fluo-8H™, AM 494 517 1 mg
21091 Fluo-8H™, AM 494 517 10×50 ug
21095 Fluo-8H™, sodium salt 494 517 10×50 ug
21096 Fluo-8L™, AM 494 517 1 mg
21097 Fluo-8L™, AM 494 517 10×50 ug
21098 Fluo-8L™, sodium salt 494 517 10×50 ug
21099 Fluo-8L™, sodium salt 494 517 1 mg
21100 Fluo-8L™, potassium salt 494 517 10×50 ug
21101 Fluo-8L™, potassium salt 494 517 1 mg
21102 Fluo-8FF™, potassium salt 494 517 10×50 ug
21103 Fluo-8FF™, potassium salt 494 517 1 mg
21104 Fluo-8FF™, AM 494 517 10×50 ug
21105 Fluo-8FF™, AM 494 517 1 mg
36307 Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 1 Plate
36308 Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 10 Plates
36309 Screen Quest™ Fluo-8 Medium Removal Calcium Assay Kit *Optimized for Difficult Cell Lines* 490 525 100 Plates
36314 Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 1 Plate
36315 Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 10 Plates
36316 Screen Quest™ Fluo-8 No Wash Calcium Assay Kit 490 525 100 Plates
36325 Screen Quest™ Fluo-4 No Wash Calcium Assay Kit 490 525 10 Plates
36326 Screen Quest™ Fluo-4 No Wash Calcium Assay Kit 490 525 100 Plates

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