Fluo-2 

(EX 490 nm/Em 515 nm, Kd 290 nM) Also known as Fluo-2 HA, Fluo-2 offers the same spectral properties as Fluo-4 combined with superior loading in many cell types as well as a slightly higher Ca²⁺ affinity. The improved loading and increased affinity can result in superior sensitivity.

Fluo-3 

(EX 505 nm/Em 525 nm, Kd 390 nM) is a structurally related predecessor of Fluo-4 which has slightly lower affinity for Ca²⁺ and a slightly red-shifted excitation and emission spectrum. For nearly 10 years it was the most commonly used single wavelength, Ca²⁺ sensor. In most cell types Fluo-4 and Fluo-2 show superior loading compared to Fluo-3, however, some have reported that Fluo-3 is superior in certain instances.

Fluo-4 

(EX 490 nm/Em 515 nm, Kd 355 nM) is the most used and the most trusted of the single-wavelength Ca²⁺ indicators. It has been the indicator of choice for countless basic research studies and has been used to screen many tens-of-millions of compounds using high-throughput screening (HTS) to discover pharmacological tools and drugs for GPCRs, and a wide variety of Ca²⁺ permeable ion channels and transporters.

ICR-I

(EX 580 nm/Em 660 nm, Kd 480 nM) represents a new generation of long sought after fluorescent Ca²⁺ indicators that emit in the red portion of the spectrum. Because of ICR-1’s unique true-red spectral properties, it provides deeper tissue penetration and dramatic background reduction in tissues that have high autofluorescence, in the presence of serum or fluorescent compounds. ICR-1 is also particularly well-suited for use with the most common fluorescent proteins (e.g. GFP/YFP) as well as many optogenetic tools. Unlike some previous red-emitting Ca²⁺-sensitive indicators (e.g. Rhod-2) that concentrate in the mitochondria, ICR-1 enjoys a predominantly cytoplasmic localization similar to the Fluo family of indicators, making it ideal for most intracellular Ca²⁺ measurements.

These indicators are particularly useful when more accurate qualification of Ca²⁺ concentrations is desired. However, to utilize the benefits of ratiometric imaging, an instrument (e.g. fluorescence microscope) capable of rapid wavelength switching is required. In the case of Fura-2 (below) an excitation source and optics compatible with 340 nm and 380 nm illumination and ultraviolet (UV) light-compatible sample containers (e.g. microscope slides) are required.

Fura-2

(Ex 340/380 nm/505 nm, Kd 145 nM) is by far the mostly commonly used dual-wavelength excitation Ca²⁺-sensitive fluorescent indicator. While Fura-2’s affinity for Ca²⁺ is higher than any of the single wavelength indicators described above, it is still well-suited to measuring changes in cytoplasmic Ca²⁺ under most conditions while enjoying the benefits of ratiometry. In addition to traditional Fura-2, we also offer Fura-2 LR. Fura-2 LR is better retained in some cell lines compared to Fura-2 and thus, may provide superior results.

We provide our Ca²⁺-fluorescent dyes in a number of different forms and formats to best suit the intended application including membrane permeable forms, membrane impermeable forms and indicators packaged in kits together with other key reagents optimized to ensure best performance.

Cell permeable, acetoxymethyl group (AM) esters

When first introduced, loading the highly negatively charged Ca²⁺-sensitive fluorescent indicators was very challenging as they existed only as highly negatively charged, membrane impermeable salts. However, the development of forms of these molecules where the negative charges are masked by non-polar esters-linked moieties (AM esters) allow the molecules to enter cells through passive diffusion. An additional advantage of the AM form is that they are also non-fluorescent and non-Ca²⁺ binding. Once inside the cell, ubiquitous intracellular esterase enzymes promote rapid hydrolysis of the AM esters leaving the active, highly polar form of the indicator trapped inside the cell.

Reagents for improving indicator loading, retention and background suppression

Although the AM forms of ION’s fluorescent Ca²⁺ indicators readily cross the plasma membrane, there are other factors that can affect how well the indicators load into cells. Because AM forms of the indicators are quite hydrophobic, it is common to use the non-ionic surfactant, Pluronic F-127, to improve their solubility in aqueous solution thus improving their loading into cells. Pluronic F-127 at the concentrations employed for loading indicators into cells is generally well tolerated. While Pluronic F-127 isn’t absolutely essential for loading most fluorescent Ca²⁺ indicators into cells, it is highly recommended.

Another factor that can affect cell loading and intracellular localization is the presence of transport proteins capable of transporting many ion-sensitive, fluorescent indicators. In many cell types, the activity of these transporters can result in compartmentalization of the indicators into intracellular compartments as well as extrusion of the indicators outside of the cell. Both of these processes can dramatically reduce the signal-to-background levels and in some cell types (e.g. CHO cells),  make adequate loading of Ca²⁺-selective fluorescent indicators nearly impossible. Fortunately, inhibitors of these transport proteins can be an effective means of improving cytoplasmic localization and indicator retention. ION offers a convenient, 100X ION-Pro inhibitor solution that may be used in conjunction with any of our Ca²⁺-sensitive fluorescent indicators.

Calcium indicator kits and complete assay solutions

While fluorescent Ca²⁺-sensitive indicators have been in widespread use for decades, not every investigator is familiar with the most up-to-date protocols and additional reagents that may be necessary for their effective use. Therefore, ION provides customers with the option to purchase all reagents commonly used to load our Ca²⁺-sensitive fluorescent indicators into most cell types with clear, easy-to-follow instructions to facilitate successful use of fluorescent, Ca²⁺ sensitive indicators in one convenient package. These Brilliant kits are supplied in a variety of sizes ranging from trial packs to the largest-scale HTS (inquire).

Brilliant Calcium Express Kit

Our Express kit is custom-tailored to customer’s needs, providing only the reagents you need in the amounts you need them. Less waste, higher reproducibility, and more convenience.

Brilliant Calcium Express is a (EX 490 nm, EM 515 nm) High-throughput, no wash calcium (Ca²⁺) assay. The most flexible solution for measuring the activity of GPCRs coupled to intracellular Ca²⁺ release. 10 plates

Brilliant Calcium Flex Kit

Our Express kit is custom-tailored to customer’s needs, providing only the reagents you need in the amounts you need them. Less waste, higher reproducibility, and more convenience.

Brilliant Calcium Express is a (EX 490 nm, EM 515 nm) High-throughput, no wash calcium (Ca²⁺) assay. The most flexible solution for measuring the activity of GPCRs coupled to intracellular Ca²⁺ release. 10 plates

Ratiometric Calcium Essentials Kit

Ratiometric Calcium Essentials kit provides the necessary reagents for conducting no wash, ratiometric calcium flux assays compatible with plate reader and fluorescence microscopy applications. Individual components are provided to give the user the flexibility needed to customize your assay.

(EX 340/380 nm, EM 505 nm, Kd 145nM) High-throughput, no wash ratiometric calcium (Ca²⁺) assay. No wash, compatible with plate reader and fluorescence microscopy applications.

Be Brilliant! Explore our line of Calcium Indicators

IPG-1

(EX 525 nm, EM 545 nm, Kd 50 mM) is the lowest affinity of the ION Potassium Green indicators. It is the indicator that is best positioned to respond to modest changes in intracellular K⁺ concentrations resulting from activation of plasma membrane K⁺ channels.

IPG-2

(EX 525 nm, EM 545 nm, Kd 18 mM) is the ION Potassium Green indicator with intermediate affinity. Currently, IPG-2 is our most popular intracellular K⁺ indicator.

IPG-4

(EX 525 nm, EM 545 nm, Kd 7 mM) has the highest K⁺ affinity of our single-wavelength indicators making it appropriate for conditions where there may be large changes in intracellular K⁺ (e.g. highly active synapses) or as an extracellular K⁺ sensor.

PBFI

(EX 340 nm, EM 380 nm, Kd 4 mM ) PBFI, AM is a potassium indicator that is ratiometric and UV light-excitable. This acetoxymethyl (AM) ester form is useful for noninvasive measurements of intracellular potassium levels.

While the IPG family of dyes are excellent fluorescent K⁺ indicators, the challenges of discriminating between K⁺ and Na⁺ are not trivial, and together with the often modest changes in intracellular or extracellular K⁺ results in relatively small signals compared to those observed with the Ca²⁺-sensitive fluorescent indicators, such as Fluo-4. In many instances, the Tl+ flux assay offers an outstanding alternative to K⁺-sensitive fluorescent indicators. The Tl⁺ flux assay takes advantage of a Tl⁺-selective fluorescent indicator, Thallos, and the fact that K⁺ channels and K⁺ transporters readily accept Tl⁺ as a K⁺ surrogate. When Tl⁺ is added to the outside of cells loaded with Thallos, Tl⁺ entering cells through K⁺ channels and K⁺ transporters results a dramatic increase in fluorescence. Today, the Tl⁺ assay is the most commonly used approach for large-scale high-throughput screening (HTS) of K⁺ channels and K⁺ transporters.

Thallos

(EX 490 nm, EM 515 nm) is the best-in-class Tl⁺-sensitive fluorescent indicator. It offers outstanding cell loading and excellent compatibility with commonly available FITC filters.

We provide our IPG family of K⁺-sensitive fluorescent indicators in membrane permeable and membrane impermeable forms. We offer Thallos as part of our convenient Brilliant Thallium Assay kits and, unlike other vendors, as a stand-alone product for investigators who prefer to use their own solutions and reagents.

Cell permeable, acetoxymethyl group (AM) esters

The native forms of K⁺-sensitive and Tl⁺-sensitive fluorescent indicators are negatively charged and membrane impermeable. However, masking the negative charge using non-polar, ester-linked moieties (AM esters) allow the molecules to enter cells through passive diffusion. Once inside the cell, ubiquitous intracellular esterase enzymes promote rapid hydrolysis of the AM esters leaving the active, highly polar form of the indicator trapped inside the cell.

Reagents for improving indicator loading and retention

Although the AM forms of ION’s fluorescent K⁺ and Tl⁺ indicators readily cross the plasma membrane, there are other factors that can affect how well the indicators load into cells. Because AM forms of the indicators are quite hydrophobic, it is common to use the non-ionic surfactant, Pluronic F-127, to improve their solubility in aqueous solution thus improving their loading into cells. Pluronic F-127 at the concentrations employed for loading indicators into cells is generally well tolerated. While Pluronic F-127 isn’t absolutely essential for loading most fluorescent K⁺ and Tl⁺ indicators into cells, it is highly recommended.

Another factor that can affect cell loading and intracellular localization is the presence of transport proteins capable of transporting many ion-sensitive, fluorescent indicators. In many cell types, the activity of these transporters can result in compartmentalization of the indicators into intracellular compartments as well as extrusion of the indicators outside of the cell. Both of these processes can dramatically reduce the signal-to-background levels and in some cell types (e.g. CHO cells),  make adequate loading of K⁺-selective fluorescent indicators nearly impossible. Fortunately, inhibitors of these transport proteins can be an effective means of improving cytoplasmic localization and indicator retention. ION offers a convenient, 100X ION-Pro inhibitor solution that may be used in conjunction with any of our K⁺-sensitive fluorescent indicators.

Be Brilliant! Explore our line of Potassium Indicators

ING-2

ION Natrium Green-2 (ING-2), formerly known as Asante Natrium Green (ANG-2), is a small, synthetic fluorochrome fused with a Na⁺-binding moiety. Under conditions where Na⁺ is not bound, the fluorescence of the sensor is significantly quenched. When Na⁺ is bound, the quenching is relieved, and the fluorescence of the sensor dramatically increases.

ING-2 (EX 525 nm, EM 545 nm, Kd 20 mM) is the best-in-class fluorescent Na⁺ sensor replacing previous Na⁺ indicators such as SBFI and CoroNa Green. Its affinity for Na⁺ is well suited to respond to changes in intracellular Na⁺ concentrations resulting from activation of plasma membrane Na⁺ permeable channels and Na⁺ transporters. It is compatible with a wide variety of detectors including fluorescent microscopes, plate readers, and flow cytometers using common filter sets like sets (e.g. YFP and FITC) as well as multiphoton approaches. ING-2 has also proven useful for high-throughput screening (HTS).

Brilliant Sodium Assays

Brilliant Sodium Assays are the first kits designed to measure intracellular sodium in an HTS-compatible format, so you can discover and characterize the effects of many tens of thousands of compounds and environmental factors on effectors of intracellular Na⁺

While ING-2 is an excellent Na⁺-sensitive, fluorescent indicator, the challenges of discriminating between K⁺ and Na⁺ are not trivial, and together with the often modest changes in intracellular Na⁺ results in relatively small signals compared to those observed with the Ca2⁺-sensitive fluorescent indicators, such as Fluo-4.

In many instances, the Tl⁺ flux assay offers an outstanding alternative to ING-2 and other Na⁺-sensitive fluorescent indicators. The Tl⁺ flux assay takes advantage of a Tl⁺-selective fluorescent indicator, Thallos, and the fact that Na⁺ permeable channels and Na⁺ transporters readily accept Tl⁺ as a Na⁺ surrogate. When Tl⁺ is added to the outside of cells loaded with Thallos, Tl⁺ entering cells through Na⁺ permeable channels and Na+ transporters results in a dramatic increase in fluorescence. Although the Tl⁺ assay is most commonly associated with high-throughput screening (HTS) of K⁺ channels, it is equally suitable for HTS of Na⁺ permeable channels and Na⁺ transporters.

Thallos

(EX 490 nm, EM 515 nm) is the best-in-class Tl⁺-sensitive fluorescent indicator. It offers outstanding cell loading and excellent compatibility with commonly available FITC filters.

We provide ING-2 in membrane permeable and membrane impermeable forms, as well as our Brilliant Sodium Assays. We offer Thallos as part of our convenient Brilliant Thallium Assay kits and, unlike other vendors, as a stand-alone product for investigators who prefer to use their own solutions and reagents.

Cell permeable, acetoxymethyl group (AM) esters

The native forms of the Na⁺-sensitive and Tl⁺-sensitive fluorescent indicators are negatively charged and membrane impermeable. However, masking the negative charge using non-polar, ester-linked moieties (AM esters) allow the molecules to enter cells through passive diffusion. Once inside the cell, ubiquitous intracellular esterase enzymes promote rapid hydrolysis of the AM esters leaving the active, highly polar form of the indicator trapped inside the cell.

Reagents for improving indicator loading, retention and background suppression

Although the AM forms of ION’s fluorescent, Na⁺ and Tl⁺ indicators readily cross the plasma membrane, there are other factors that can affect how well the indicators load into cells. Because AM forms of the indicators are quite hydrophobic, it is common to use the non-ionic surfactant, Pluronic F-127, to improve their solubility in aqueous solution thus improving their loading into cells. Pluronic F-127 at the concentrations employed for loading indicators into cells is generally well tolerated. While Pluronic F-127 isn’t absolutely essential for loading most fluorescent Na⁺ and Tl⁺ indicators into cells, it is highly recommended.

Another factor that can affect cell loading and intracellular localization is the presence of anion transport proteins in both plasma and intracellular membranes. In many cell types, the activity of these transporters can result in compartmentalization of the indicators into intracellular compartments as well as extrusion of the indicators outside of the cell. Both of these processes can dramatically reduce the signal-to-background levels and in some cell types (e.g. CHO cells), make adequate loading of Na⁺ and Tl⁺ sensitive fluorescent indicators nearly impossible. Fortunately, probenecid, an organic anion transport inhibitor can be an effective means of inhibiting the transporters, improving cytoplasmic localization and indicator retention. ION offers a convenient, 100X probenecid solution that may be used in conjunction with our Na⁺ and Tl⁺-sensitive fluorescent indicators. While probenecid is generally well-tolerated over the time course of typical experiments using Na⁺ and Tl⁺-sensitive fluorescent indicators, effects on the activity of TRP channels has been reported.

Be Brilliant! Explore our line of Sodium Indicators

Thallos is a small, synthetic fluorochrome which incorporates a Tl⁺-binding moiety with excellent selectivity for Tl⁺ over most other physiologically relevant metal cations (e.g. Ca²⁺). Under conditions where Tl⁺ is not bound, the fluorescence of the sensor is significantly quenched. When Tl⁺ is bound, the quenching is relieved, and the fluorescence of the sensor dramatically increases.

Thallos is compatible with a wide variety of detectors including fluorescent microscopes, plate readers, flow cytometers. Over the last 20 years, since Dr. David Weaver invented the Tl⁺ flux assay, Tl⁺-sensitive indicators have found numerous uses including high-throughput screening (HTS) of K⁺ channel, Na⁺ channel, other monovalent cation channels, some monovalent cation transporters, and the Gi/o class of G protein-coupled receptors (GPCR) discovery.

Thallos

(EX 490 nm, EM 515 nm) is the best-in-class Tl⁺-sensitive fluorescent indicator. It offers outstanding cell loading and excellent compatibility with commonly available FITC filters.

Brilliant Thallium Flex

(EX 490 nm, EM 515 nm) High-throughput, no wash thallium (Tl⁺) assay. The most flexible solution for measuring the activity of potassium (K⁺), sodium (Na⁺), and non-selective cation channels and their effectors including transporters and GPCRs. 10 plates

Brilliant Thallium Express

(EX 490 nm, EM 515 nm) High-throughput, no wash thallium (Tl⁺) assay. A streamlined solution for large-scale screening of potassium (K⁺), sodium (Na⁺), and non-selective cation channels and their effectors including transporters and GPCRs. 100 plates

Cell permeable, acetoxymethyl group (AM) esters

The native form of Thallos is negatively charged and membrane impermeable. However, masking the negative charge using non-polar, ester-linked moieties (AM esters) allow the molecules to enter cells through passive diffusion. Once inside the cell, ubiquitous intracellular esterase enzymes promote rapid hydrolysis of the AM esters leaving the active, highly polar form of the indicator trapped inside the cell.

Reagents for improving indicator loading, retention and background suppression

Although the AM form of Thallos indicator readily crosses the plasma membrane, there are other factors that can affect how well Thallos loads into cells. Because Thallos-AM is quite hydrophobic, it is common to use the non-ionic surfactant, Pluronic F-127, to improve its solubility in aqueous solution thus improving its loading into cells. Pluronic F-127 at the concentrations employed for loading indicators into cells is generally well tolerated. While Pluronic F-127 isn’t absolutely essential for loading Thallos into cells, it is highly recommended.

Another factor that can affect cell loading and intracellular localization is the presence of transport proteins capable of transporting many ion-sensitive, fluorescent indicators. In many cell types, the activity of these transporters can result in compartmentalization of the indicators into intracellular compartments as well as extrusion of the indicators outside of the cell. Both of these processes can dramatically reduce the signal-to-background levels and in some cell types (e.g. CHO cells),  make adequate loading of Tl⁺-selective fluorescent indicators nearly impossible. Fortunately, inhibitors of these transport proteins can be an effective means of improving cytoplasmic localization and indicator retention. ION offers a convenient, 100X ION-Pro inhibitor solution that may be used in conjunction with any of our Tl⁺-sensitive fluorescent indicators.

Be Brilliant! Explore our line of Thallium Indicators

Intracellular enzyme activity and dye retention is a hallmark of viable cells. During cell death, increased plasma membrane permeability causes enzyme leakage and a reduction in activity. Dyes that measure esterase activity are modified with ester-moieties, which help them passively diffuse through cell membranes and render the dyes non-fluorescent. Once inside the cell, ubiquitous esterases present in the cytosol cleave ester-moieties, activating dye fluorescence and trapping the dye within the cell. ION sells Calcein AM in multiple formats (dry or in a prepared solution) and in combination with Ethidium Homodimer I as part of ION Vital – Viability so you can simultaneously detect dead cells.

Calcein AM

(Ex/Em 495 nm/515 nm) – Calcein AM is a membrane-permeant, non-fluorescent form of calcein that is converted to green fluorescent calcein in viable cells, resulting in uniform cytosolic fluorescence. Calcein is well retained within the cytosol of most healthy cells with intact cell membranes.

BCECF AM

(Ex/Em 490 nm/535 nm) – BCECF AM is the most popular green fluorescent, intracellular pH indicator, however it can also be used as a marker of intracellular esterase activity. For this application, BCECF should be used in non-ratiometric mode using standard FITC excitation and emission settings.

ION Vital – Viability Kit

This kit combines Ethidium Homodimer I and Calcein AM to provide a two-color, fluorescence-based assay to discriminate between live and dead cells.

A loss of plasma membrane integrity is an indicator of cell death. Nucleic acid-binding, cell impermeant dyes, like Ethidium Homodimer I (EthD-I), can be used to label the nuclei of cells with compromised plasma membranes. These dyes are excluded from intact, healthy cells and exhibit minimal fluorescence in the absence of nucleic acids. Once the dye crosses the cell membrane and binds to nucleic acids (DNA) inside the cell, it displays a significant increase in fluorescence. ION sells EthD-I in multiple formats (dry or in a prepared solution) and in combination with Calcein AM as part of ION Vital – Viability so you can simultaneously detect viable cells.

Ethidium Homodimer I

(Ex/Em: 528 nm/617 nm) – EthD-I is a membrane-impermeable, high-affinity, nucleic acid stain that selectively labels dead cells with compromised plasma membranes.

ION Vital – Viability Kit

This kit combines Ethidium Homodimer I and Calcein AM to provide a two-color, fluorescence-based assay to discriminate between live and dead cells.

Mitochondrial membrane potential is one of the driving forces behind mitochondrial ATP synthesis, and is necessary for maintaining cell homeostasis. During early stages of apoptosis, mitochondrial function and membrane integrity are disrupted by the activation of apoptotic proteins and subsequent release of cytochrome C, mitochondrial Ca2+ stores, and other components. Membrane potential sensitive dyes, such as JC-1 and JC-10, can be used to monitor the loss of mitochondrial membrane polarization observed during apoptosis. These dyes compartmentalize in healthy mitochondria, leading to the formation of aggregates that exhibit orange fluorescence. When mitochondrial membrane potential is lost during apoptosis, these dyes no longer accumulate and return to green fluorescent monomers. ION sells JC-10 individually and as part of our optimized ION Vital Assay line of products

JC-10

(Ex/Em: 490,540 nm/525, 590nm) – JC-10 is a mitochondrial membrane potential probe. It possesses superior aqueous solubility compared to its better known analogue, JC-1. At low concentrations, JC-10 is monomeric and emits a green fluorescence. JC-10 accumulates in healthy mitochondria, forming J-aggregates that exhibit an orange fluorescence. Its potentiometric behavior allows for ratiometric analysis of mitochondrial membrane potential, where a shift from orange to green fluorescence is indicative of compromised mitochondria.

ION Vital – MitoVolt

MitoVolt is a mitochondrial membrane potential assay kit that uses JC-10, a potentiometric dye that is more soluble than JC-1. It is an ideal solution for detecting changes in mitochondrial membrane potential due to cell apoptosis or other stress-inducing phenomena, and is compatible with fluorescence microscopy, flow cytometry, and plate reader applications.

Be Brilliant! Explore our line of products for Cell Health

Fluo-4 

(EX 490 nm/Em 515 nm, Kd 355 nM) is the most used and the most trusted of the single-wavelength Ca²⁺ indicators. It has been the indicator of choice for countless basic research studies and has been used to screen many tens-of-millions of compounds using high-throughput screening (HTS) to discover pharmacological tools and drugs for GPCRs, and a wide variety of Ca²⁺ permeable ion channels and transporters.

Fluo-2 

(EX 490 nm/Em 515 nm, Kd 290 nM) Also known as Fluo-2 HA, Fluo-2 offers the same spectral properties as Fluo-4 combined with superior loading in many cell types as well as a slightly higher Ca²⁺ affinity. The improved loading and increased affinity can result in superior sensitivity.

Brilliant Calcium Express Kit

Our Express kit is custom-tailored to customer’s needs, providing only the reagents you need in the amounts you need them. Less waste, higher reproducibility, and more convenience.

Brilliant Calcium Express is a (EX 490 nm, EM 515 nm) High-throughput, no wash calcium (Ca²⁺) assay. The most flexible solution for measuring the activity of GPCRs coupled to intracellular Ca²⁺ release. 10 plates

Brilliant Calcium Flex Kit

Our Express kit is custom-tailored to customer’s needs, providing only the reagents you need in the amounts you need them. Less waste, higher reproducibility, and more convenience.

Brilliant Calcium Express is a (EX 490 nm, EM 515 nm) High-throughput, no wash calcium (Ca²⁺) assay. The most flexible solution for measuring the activity of GPCRs coupled to intracellular Ca²⁺ release. 10 plates

A key signaling pathway for another major class of GPCRs, Gi/o-coupled GPCRs, is through activation of G protein-gated Inward Rectifying Potassium (K⁺) channels, better known as GIRK channels. Not only is the GPCR-mediated modulation of GIRK channels of great physiological importance, it also provides a convenient means of measuring Gi/o GPCR activity using Tl⁺ flux. This GIRK assay approach offers some key advantages compared to other approaches used to measure the activity of Gi/o GPCRs. Unlike the most common approaches which utilize fixed-endpoint measures of cAMP, the GIRK assay is a real-time measure of GPCR activation and does not require non-physiological elevations of intracellular cAMP. Unlike approaches which utilize chimeric Gα subunits (e.g. Gqi5) to induced Gi/0 GPCRs to promote intracellular Ca2+ release, the GIRK assay enables measurement of Gi/o GPCR activity through their native Gβ/γ coupling mechanism.

ION offers Tl⁺ flux reagents and assay kits to help enable researchers to utilize GIRK-based GPCR activity assays.

Brilliant Thallium Assay

(EX 490 nm, EM 515 nm) High-throughput, no wash thallium (Tl⁺) assay. A streamlined solution for large-scale screening of potassium (K⁺), sodium (Na⁺), and non-selective cation channels and their effectors including transporters and GPCRs. 100 plates

Thallos

(EX 490 nm, EM 515 nm) is the best-in-class Tl⁺-sensitive fluorescent indicator. It offers outstanding cell loading and excellent compatibility with commonly available FITC filters.

Be Brilliant! Explore our line of GPCRs Assays

ION Biosciences’ Brilliant Calcium Assay series is a total assay solution for multi-well plate-based, high-throughput measurements of dynamic changes in intracellular Ca²⁺. The Flex and  Express kits represent different sizes and packaged configurations for various screening scenarios.  Each assay kit is designed to be a simple, fast, and reliable fluorescence-based assay.

Whether your platform is FLIPR®,  FlexStation®, or FDSS, ION’s assay kits will provide a  smooth process for your assay development.

There are no intermediate wash-steps required with these kits. In each version, you will find all the reagents necessary for preparation to use as a no-wash or washed assays for adherent and non- adherent  cells.

Brilliant Sodium Assays

High-throughput, no wash sodium (Na⁺) assay for measuring changes in intracellular Na⁺ caused by effectors of Na⁺ channels and transporters

SPECIFICATIONS

Excitation	Emission	MW:
525nm	545nm	1084

PRODUCT DESCRIPTION

ION’s Brilliant Sodium Assay is a total assay solution for multi-well plate-based, high-throughput measurements of changes in intracellular Na⁺ mediated through a wide-variety of plasma membrane and intracellular sodium channels and transporters. In multi-well, plate-based formats, the Brilliant Sodium Assay can be used to discover and characterize the effects of many tens-of-thousands of compounds and environmental factors on effectors of intracellular Na⁺. ION’s Brilliant Sodium Assay provides all the reagents necessary for use as a wash or no-wash assay with adherent or non-adherent cells. The optional use of a probenecid solution and an extracellular background masking solution (TRS) offers the ultimate in compatibility for cells types which are difficult to load with fluorescent Na⁺ indicators (e.g. Chinese Hamster Ovary, CHO cells) and when performing assays in complete, serum-containing cell culture medium is desired.

ION’s Brilliant Sodium Assay is compatible with fluorescence microscopes, flow cytometers, and plate readers capable of detecting fluorescein or more optimally, yellow fluorescent protein (YFP).

Our Flex kit provides all necessary reagents in a format to maximize flexibility for your assay design and customization challenges. If you want a kit designed just for you, inquire about our Brilliant Sodium Express Kit.

ION Biosciences Brilliant Thallium Assay is a total assay solution for multi-well plate-based, high-throughput measurements of Tl⁺ flux through K⁺, Na⁺, non-selective cation channels, and some Na⁺ or K⁺ transporters. The ION Biosciences Brilliant Thallium Assay is also useful for a wide range of effectors of ion channels and transporters including G protein-coupled receptors, lipid and protein kinase, for example. In multi-well, plate-based formats, the Brilliant Thallium Assay can be used to discover and characterize the effects of tens to many tens-of-thousands of compounds and environmental factors on effectors of Tl⁺ flux.

ION VITAL – Viability Kit

Two-color, fluorescence-based assay to discriminate between live and dead cells

SPECIFICATIONS

Excitation	Emission
Live 495 nm   Dead 528 nm	Live 515 nm   Dead 617 nm

PRODUCT DESCRIPTION

ION Vital – Viability kit can be used to quantify live and dead cells within eukaryotic cell suspensions or adherent cultures, 3D cultures, organoids, and some non-fixed tissues. Cannot be used for yeast or bacteria. When following our protocol, ION Vital—Viability kit provides enough reagents to make 150 mL of working solution, enough for fifteen 96-well plates or 1,500 flow cytometry samples. The actual number of assays will vary according to optimal dye concentrations for your application.

ION VITAL – MitoVolt

Mitochondrial membrane potential assay kit that uses JC-10, a membrane potential sensitive dye that is more soluble than JC-1.

SPECIFICATIONS

Excitation	Emission	MW:	Solubility:	Purity (minimum):
490 540nm	525 590nm	~600	DMSO or H2O	>98%

PRODUCT DESCRIPTION

ION Vital – MitoVolt assay kit is the ideal solution for detecting changes in mitochondrial membrane potential due to cell apoptosis or other stress-inducing phenomena. ION Vital – MitoVolt is compatible with fluorescence microscopy, flow cytometry, and plate reader applications.

JC-10 is a mitochondrial membrane potential probe. It possesses superior aqueous solubility compared to its better known analogue, JC-1. At low concentrations, JC-10 is monomeric and emits a green fluorescence. JC-10 accumulates in healthy mitochondria, forming J-aggregates that exhibit an orange fluorescence. Mitochondrial depolarization, a key marker of cellular apoptosis, results in a loss of JC-10 accumulation and a reversal to its monomeric form. This reversible behavior of JC-10 allows for ratiometric analysis of mitochondrial membrane potential, where a shift from orange (Ex/Em: 540nm/590nm) to green fluorescence (Ex/Em: 490nm/525nm) is indicative of compromised mitochondria.

ION Vital – MitoVolt can be used to monitor and/or visualize mitochondrial membrane potential as a static endpoint or in real-time. When following our protocol, ION Vital – MitoVolt provides enough reagents to make 25 mL of working solution, enough for five 96-well plates or 500 flow cytometry samples. The actual number of assays will vary according to optimal dye concentrations and assay volumes for your application.

Multidrug Resistance Activity Kit

Two-color, fluorescence-based assay to discriminate between live and dead cells

PRODUCT DESCRIPTION

ION’s Multidrug Resistance (MDR) Activity kit is an effective solution for detecting MDR1 and MRP1 activity and compounds susceptible to MDR-mediated efflux. ION’s MDR Activity kit is compatible with fluorescence microscopy, flow cytometry, and fluorescence plate readers using FITC/fluorescein settings.

Calcein AM is a membrane-permeant, non-fluorescent dye that enters cells passively. Once inside the cytosol of cells, intracellular esterases convert it to fluorescent Calcein (Ex/Em: 495 nm/515 nm), resulting in uniform cytosolic fluorescence. Drug efflux transporters, such as P-glycoprotein (Pgp, MDR1) and multidrug-resistance-associated protein (MRP1), actively extrude Calcein AM from inside the cell before esterases can convert it to Calcein. The presence of additional MDR substrates or inhibitors of MDR expression results in decreased Calcein AM efflux, causing a measurable increase in intracellular fluorescence. In addition to identifying MDR substrates and inhibitors, this kit can also be used to evaluate the activity of MDR transporters in cells.
When following our protocol, ION’s MDR Activity kit provides enough reagents to make 100 mL of working solution, enough for ten 96- or 384-well plates or 80 flow cytometry samples. The actual number of assays will vary according to optimal dye concentrations for your application.