Shop All Cell Viability Kits

LIVE/DEAD™ Fixable Violet Dead Cell Stain Kit, for 405 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Violet Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a violet laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Low compensation—minimal spectral overlap between other fluorophores

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Violet Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Violet Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Low compensation
The LIVE/DEAD™ Fixable Violet Stain was selected based on its fluorescent properties to minimize compensation between other violet dyes and dyes that excite off of the 488 nm blue laser. The violet-fluorescent reactive dye has an excitation maximum of ~416 nm and is excited well with the 405 nm violet laser, and it has an emission maxima of ~451 nm, so it can be collected in the first channel on most violet laser flow cytometers.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

PrestoBlue™ Cell Viability Reagent (Invitrogen™)

Get high quality cell viability results and instant time savings with PrestoBlue® Cell Viability Reagent. PrestoBlue® is a ready to use cell permeable resazurin-based solution that functions as a cell viability indicator by using the reducing power of living cells to quantitatively measure the proliferation of cells. When added to cells, the PrestoBlue® reagent is modified by the reducing environment of the viable cell and turns red in color, becoming highly fluorescent. This color change can be detected using fluorescence or absorbance measurements.

The PrestoBlue® Cell Viability Reagent allows you to:

• Save time with an incubation step as short as 10 minutes.
• Obtain high quality results with a large dynamic range
• Experience convenience with the add and read homogenous format
• Monitor living cells and perform downstream functional assays


10 Minute Incubation
The PrestoBlue® Cell Viability Reagent is the only live-cell viability reagent on the market able to provide robust data typically in as little as 10 minutes following reagent addition. All other resazurin-based cell viability reagents on the market require a one to four hour incubation with the reagent prior to obtaining data.

High Quality Results
Based on the cell type and incubation time, PrestoBlue® Cell Viability Reagent can detect as few as 12 cells per well in a 384 well plate. After ten minutes of incubation the PrestoBlue® Reagent can linearly detect cells down to 98 cells⁄well with a Z’ value of greater than 0.5.

Homogenous Assay Format
The PrestoBlue® Cell Viability Reagent is an addition-only reagent. Without the cell lysis or solubilization steps required by other assays on the market, hands-on time is minimized.

Live Cell Assay
The PrestoBlue® Cell Viability Reagent does not require cell lysis. Cells may be incubated for up to 24 hours in the presence of PrestoBlue® Cell Viability Product. Simply remove the reagent from the cells and replace it with growth medium for further proliferation.

LIVE/DEAD™ Fixable Aqua Dead Cell Stain Kit, for 405 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Aqua Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a violet laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Low compensation—minimal spectral overlap between other fluorophores

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Aqua Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Aqua Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Low compensation
The LIVE/DEAD™ Fixable Aqua Stain was selected based on its fluorescent properties to minimize compensation between other violet dyes and dyes that excite off of the 488 nm blue laser. The aqua-fluorescent reactive dye has an excitation maximum of ~375 nm, but it is excited well with the 405 nm violet laser, and it has an emission maxima of ~512 nm, so it can be collected in the second channel on most violet laser flow cytometers.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

CellROX™ Deep Red Flow Cytometry Assay Kit (Invitrogen™)

The CellROX™ Deep Red Flow Cytometry Assay Kit enables the flow cytometric detection of reactive oxygen species (ROS) in live cells. The kit includes the novel, fluorogenic CellROX™ Deep Red Reagent, as well as SYTOX™ Blue dead cell stain, N-acetyl cysteine (an antioxidant, for negative control), and tert-butyl hydroperoxide solution (TBHP, an inducer of ROS).

View a selection guide for all CellROX® Reagents and Kits.

The CellROX™ Deep Red Flow Cytometry Assay Kit features:

• Fluorogenic probe formulated for flow cytometry that is oxidized in the presence of ROS
• Multicolor compatibility—minimal overlap with fluorophores excited by other laser lines, allowing easy multiplexing with other reagents
• Simple protocol—cells can be stained in complete media or other appropriate buffer, no need for serum free media

The CellROX™ Deep Red Detection Reagent is cell-permeable and non-fluorescent or very weakly fluorescent while in the reduced state. Upon oxidation, the reagent exhibits a strong fluorogenic signal that has absorption/emission maxima of 644/665 nm and remains localized in the cytoplasm. When used together with the included SYTOX™ Blue Dead Cell Stain, oxidatively stressed and non-stressed cells are reliably distinguished from dead cells by flow cytometry.

FUN™ 1 Cell Stain (Invitrogen™)

FUN® 1 is a unique two-color fluorescent viability probe for yeast and fungi. The FUN® 1 stain passively diffuses into a variety of cell types and initially stains the cytoplasm with a diffusely distributed green fluorescence. However, in several common species of yeast and fungi, subsequent processing of the dye by live cells results in the formation of distinct vacuolar structures with compact form that exhibit a striking red fluorescence, accompanied by a reduction in the green cytoplasmic fluorescence. Formation of the intravacuolar structures requires both plasma membrane integrity and metabolic capability. Dead cells fluoresce bright yellow-green, with no discernable red structures.

BacLight™ Green Bacterial Stain (Invitrogen™)

The BacLight Green (Cat. no. B-35000) and BacLight Red (Cat. no. B-35001) bacterial stains are fluorescent labeling reagents for detecting and monitoring bacteria. These two dyes are not nucleic acid stains. Bacteria stained with the BacLight Green and BacLight Red bacterial stains exhibit bright green and red fluorescence (absorption/emission ~480/516 and ~581/644 nm, respectively), and can be resolved using the appropriate flow cytometric channels or fluorescence microscopy filters. The BacLight bacterial stains are compatible with formaldehyde or alcohol fixation methods.

View additional information about all microbiological analysis products.

LIVE/DEAD™ Fixable Far Red Dead Cell Stain Kit, for 633 or 635 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Far-Red Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a red laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Bright signal—allows for easy distinction between live/dead cells in single channel

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Far-Red Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Far-Red Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Optimal brightness
The LIVE/DEAD™ Fixable Far-Red Stain was selected based on its fluorescent properties to provide a bright signal when excited with a red laser. The far-red fluorescent reactive dye has an excitation maximum of ~633 nm making it ideal for use with the red or HeNe laser with an emission of ~655 nm. Since live and dead cells can be discriminated using a single dye and a single channel of a flow cytometer, it is an ideal choice for multi-color experiments.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

LIVE/DEAD™ Sperm Viability Kit (Invitrogen™)

The LIVE/DEAD Sperm Viability Kit provides a novel fluorescence-based assay for analyzing the viability and fertilizing potential of sperm by fluorescence microscopy or flow cytometry. Membrane-permeant SYBR® 14 nucleic acid stain labels live sperm with green fluorescence, and membrane-impermeant propidium iodide labels the nucleic acids of membrane-compromised sperm with red fluorescence.

LIVE/DEAD™ BacLight™ Bacterial Viability Kit, for microscopy (Invitrogen™)

The LIVE/DEAD BacLight Bacterial Viability Kit *for microscopy* is a convenient and easy-to-use kit for monitoring the viability of bacterial populations as a function of the membrane integrity of the cell. Cells with a compromised membrane that are considered to be dead or dying will stain red, whereas cells with an intact membrane will stain green.

CellROX™ Green Flow Cytometry Assay Kit (Invitrogen™)

The CellROX™ Green Flow Cytometry Assay Kit enables the flow cytometric detection of reactive oxygen species (ROS) in live cells. The kit includes the novel, fluorogenic CellROX™ Green Reagent, as well as SYTOX™ Red Dead Cell Stain, N-acetyl cysteine (an antioxidant, for negative control), and tert-butyl hydroperoxide solution (TBHP, an inducer of ROS).

View a selection guide for all CellROX® Reagents and Kits.

The CellROX™ Green Flow Cytometry Assay Kit features:

• Fluorogenic probe formulated for flow cytometry that is oxidized in the presence of ROS
• Multicolor compatibility—minimal overlap with fluorophores excited by other laser lines, allowing easy multiplexing with other reagents
• Simple protocol—cells can be stained in complete media or other appropriate buffer, no need for serum free media

The CellROX™ Green Detection Reagent is cell-permeable and non-fluorescent or very weakly fluorescent while in the reduced state. Upon oxidation, the reagent binds DNA and exhibits a strong fluorogenic signal that has absorption/emission maxima of 508/525 nm and remains localized to the nucleus and cytoplasm. When used together with the included SYTOX™ Red Dead Cell Stain, oxidatively stressed and nonstressed cells are reliably distinguished from dead cells by flow cytometry.

Tali™ Viability Kit - Dead Cell Red (Invitrogen™)

The Tali® Viability Kit - Dead Cell Red is a ready-to-use solution of propidium iodide (PI) that has been validated for use with the Tali® Image-Based Cytometer. PI is a live cell-impermeant fluorogenic DNA-binding dye that has been extensively used to identify necrotic cells.

Key Features of Tali® Viability Kit - Dead Cell Red:

• Impermeant to live cells
• Easily enters and binds to nucleic acids in necrotic cells

After staining a cell population using Dead Cell Red™, dead cells display red fluorescence upon excitation. Tali® Viability Kit - Dead Cell Red can be used to identify dead cells in a population of unstained cells, or in a population of GFP-expressing cells.

HCS LIVE/DEAD™ Green Kit (Invitrogen™)

The HCS LIVE⁄DEAD® Green Kit measures cytotoxicity by high content analysis with the Image-iT® DEAD Green™ viability stain – a non-fluorescent and cell impermeant compound that exhibits a strong fluorescent enhancement upon binding to DNA. Drugs and test compounds leading to serious cell injuries, including plasma membrane permeability, allow entry of the Image-iT® DEAD Green™ viability stain. This two-color fluorescence assay also employs the use of a cell permeant nuclear segmentation tool that stains both live and dead cells, reflecting the total cell number within the sample. For total cell staining, the kit includes both a blue-fluorescent Hoechst 33342 and a near infrared-fluorescent, HCS NuclearMask™ Deep Red reagent. Either of these segmentation tools may be used with Image-iT® DEAD Green™ viability stain for excellent discrimination of live and dead cells that survives fixation and permeabilization for combination with additional parameters of cytotoxicity or other biomarkers. The kit contains sufficient reagents for performing 2, 96-well plates.

LIVE/DEAD™ Fixable Near-IR Dead Cell Stain Kit, for 633 or 635 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Near-IR Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a red laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability

• Robust—staining pattern is the same before and after fixation

• Bright signal—allows for easy distinction between live/dead cells in single channel

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Near-IR Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Near-IR Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Optimal brightness
The LIVE/DEAD™ Fixable Near-IR stain was selected based on its fluorescent properties to provide a bright signal when excited with a red laser. The near-IR fluorescent reactive dye has an excitation maximum of ~633 nm making it ideal for use with the red or HeNe laser with an emission of ~750 nm. Since live and dead cells can be discriminated using a single dye and a single channel of a flow cytometer, it is an ideal choice for multi-color experiments.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

BacLight™ Red Bacterial Stain (Invitrogen™)

The BacLight Green (Cat. no. B-35000) and BacLight Red (Cat. no. B-35001) bacterial stains are fluorescent labeling reagents for detecting and monitoring bacteria. These two dyes are not nucleic acid stains. Bacteria stained with the BacLight Green and BacLight Red bacterial stains exhibit bright green and red fluorescence (absorption/emission ~480/516 and ~581/644 nm, respectively), and can be resolved using the appropriate flow cytometric channels or fluorescence microscopy filters. The BacLight bacterial stains are compatible with formaldehyde or alcohol fixation methods.

View additional information about all microbiological analysis products.

LIVE/DEAD™ Cell Imaging Kit (488/570) (Invitrogen™)

The LIVE/DEAD® Cell Imaging Kit is a sensitive two-color fluorescence cell viability assay optimized for FITC and Texas Red® filters. Quick and easy to use, the kit allows discrimination between live and dead cells with two probes that measure recognized parameters of cytotoxicity and cell viability—intracellular esterase activity and plasma membrane integrity.

The LIVE/DEAD® Cell Imaging Kit *488/570* offers:

Fast, simple determination of live and dead cells

• Accuracy with convenience
• Sensitive probes ideal for FITC and Texas Red filters


Dual Probe-Based Assay for Imaging Platforms
Just like our popular LIVE/DEAD® Viability/Cytotoxicity assay, the new LIVE/DEAD® Cell Imaging Kit is based on a cell-permeable dye for staining of live cells and a cell-impermeable dye for staining of dead and dying cells, which are characterized by compromised cell membranes. To adapt this important assay for imaging platforms, the LIVE/DEAD® Cell Imaging Kit components were optimized for the common green and red imaging filters used with FITC and Texas Red. The live cell component produces an intense, uniform green fluorescence in live cells (ex/em 488 nm/515 nm). The dead cell component produces a predominantly nuclear red fluorescence (ex/em 570nm/602 nm) in cells with compromised cell membranes, a strong indicator of cell death and cytotoxicity (Fig 1).

Quick, Exact Determination of Viability and Cytotoxicity
The LIVE/DEAD® Cell Imaging kit provides very sensitive detection of key measures of cell health: viability, live/dead ratio, and cytotoxicity. The components of the LIVE/DEAD® Cell Imaging kit are configured for ease of use with minimal dilutions.

Assay Principle
With the LIVE/DEAD® Cell Imaging Kit, live cells are distinguished by the presence of ubiquitous intracellular esterase activity as determined by the enzymatic conversion of the virtually non-fluorescent cell-permeant calcein AM to the intensely fluorescent calcein, which is well-retained within live cells. The red component of the LIVE/DEAD® Cell Imaging Kit is cell-impermeant and therefore only enters cells with damaged membranes. In dying and dead cells a bright red fluorescence is generated upon binding to DNA. Background fluorescence levels are inherently low with this assay technique because the dyes are virtually non-fluorescent before interacting with cells. The fluorophores in the LIVE/DEAD® Cell Imaging Kit were selected for their brightness, spectral properties (FITC and Texas Red filters), and ease of use. Packaged for workflow convenience, they allow for effortless and quick determination of the fractions of live and dead cells in a population.

See other Molecular Probes imaging tools and reagents

LIVE/DEAD™ Fixable Yellow Dead Cell Stain Kit, for 405 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Yellow Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a violet laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Low compensation—minimal spectral overlap between other fluorophores

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Yellow Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Yellow Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Low compensation
The LIVE/DEAD™ Fixable Yellow Stain was selected based on its fluorescent properties to minimize compensation between other violet dyes and dyes that excite off of the 488 nm blue laser. The yellow-fluorescent reactive dye has an excitation maximum of ~405 nm, but it is excited well with the 405 nm violet laser, and it has an emission maxima of ~570 nm, so it can be collected in the second or third channel on most violet laser flow cytometers.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

PrestoBlue™ HS Cell Viability Reagent (Invitrogen™)

PrestoBlue HS Cell Viability Reagent is a ready-to-use resazurin-based solution that functions as a cell health indicator by using the reducing power of living cells to quantitatively measure viability. Upon entering living cells, resazurin is reduced to resorufin, a compound that is red in color and highly fluorescent. High background fluorescence caused by various contaminants reduces the performance of resazurin-based reagents. To improve the performance an innovative purification process was developed that removes these contaminants. This highly purified, non-toxic resazurin was used in the standard PrestoBlue formulation, creating the PrestoBlue HS Cell Viability Reagent. Changes in viability can be easily detected using either an absorbance- or fluorescence-based plate reader. The PrestoBlue HS Cell Viability Reagent has been optimized for the fast and reliable detection of mammalian cell viability.

PrestoBlue HS Cell Viability Reagent features include:
• Removal of contaminants from resazurin—displays a >50% reduction in background fluorescence
• Signal-to-background ratio increased by >100%—results in large assay signal window
• Highly sensitive reagent with a linear response—detects as few as 10 cells per well
• Convenient add-and-read format—no mixing, no washing, no cell lysis, and compatible with either fluorescence- or absorbance-based instrumentation
• Optimized for reliable detection of mammalian cell viability in only 10 minutes

Measuring changes in cell viability is a fundamental method for assessing cell health, determining genotoxicity, and evaluating anti-cancer drugs. Cell health can be monitored by detecting changes in several key indicators, including changes to plasma membrane integrity, DNA synthesis, DNA content, enzyme activity, presence of ATP, and cellular reducing environment.

Monitoring changes to the cellular reducing environment or metabolic activity by using resazurin-based reagents is a well-established and reliable indicator of cell viability or death. Upon entering living cells, the cellular reducing environment reduces resazurin to resorufin, a compound that is red in color and highly fluorescent. Viable cells continuously convert resazurin to resorufin, increasing the overall fluorescence of the medium surrounding the cells. Additionally, the conversion of resazurin to resorufin results in a pronounced color change, thus cell viability can also be detected using absorbance-based plate readers.

As a consequence of the synthesis and manufacturing processes, all resazurin-based reagents contain a detectable amount of resorufin contamination. The amount of contamination can vary greatly between sources of the material and manufacturing conditions, contributing to differences in detectable background fluorescence. An innovative process was developed that removes the contaminating resorufin, resulting in the highly pure resazurin used in PrestoBlue HS Cell Viability Reagent. This highly pure resazurin produces a >50% decrease in background fluorescence and a >100% increase in the signal-to-background ratio. Mammalian cell viability can be detected after a 10-minute incubation with PrestoBlue HS Cell Viability Reagent. Since no lysis is required, the diluted PrestoBlue HS solution can be removed and replaced with complete growth medium, for further culturing of the cells.

alamarBlue™ HS Cell Viability Reagent (Invitrogen™)

alamarBlue HS Cell Viability Reagent is a ready-to-use resazurin-based solution that functions as a cell health indicator by using the reducing power of living cells to quantitatively measure viability. Upon entering living cells, resazurin is reduced to resorufin, a compound that is red in color and highly fluorescent. High background fluorescence caused by various contaminants reduces the performance of resazurin-based reagents. To improve the performance, an innovative purification process was developed that removes these contaminants. This highly purified, non-toxic resazurin was used in the standard alamarBlue formulation, creating the multiple-component alamarBlue HS Cell Viability Reagent. Changes in viability can be easily detected using either an absorbance- or fluorescence-based plate reader. The alamarBlue HS Cell Viability Reagent has broad applicability and can be used with various human and animal cell lines, bacteria, plant, and fungi.

alamarBlue HS Cell Viability Reagent features include:
Removal of contaminants from resazurin—displays a >50% reduction in background fluorescence
Signal-to-background ratio increased by >100%—results in large assay signal window
Highly sensitive reagent with a linear response—detects as few as 20 cells per well
Convenient add-and-read format—no mixing, no washing, no cell lysis, and compatible with either fluorescence- or absorbance-based instrumentation
Measures viability from many diverse cell types—including mammalian cells, bacteria, plant, and fungi

Measuring changes in cell viability is a fundamental method for assessing cell health, determining genotoxicity, and evaluating anti-cancer drugs. Cell health can be monitored by detecting changes in several key indicators, including changes to plasma membrane integrity, DNA synthesis, DNA content, enzyme activity, presence of ATP, and cellular reducing environment.

Monitoring changes to the cellular reducing environment or metabolic activity by using resazurin-based reagents is a well-established and reliable indicator of cell viability or death. Upon entering living cells, the cellular reducing environment reduces resazurin to resorufin, a compound that is red in color and highly fluorescent. Viable cells continuously convert resazurin to resorufin, increasing the overall fluorescence of the medium surrounding the cells. Additionally, the conversion of resazurin to resorufin results in a pronounced color change, thus cell viability can also be detected using absorbance-based plate readers.

As a consequence of the synthesis and manufacturing processes, all resazurin-based reagents contain a detectable amount of resorufin contamination. The amount of contamination can vary greatly between sources of the material and manufacturing conditions, contributing to differences in detectable background fluorescence. More importantly, the contaminating resorufin reduces the signal to background ratio and dynamic range of the assay. An innovative process was developed that removes the contaminating resorufin, resulting in the highly pure resazurin used in alamarBlue HS Cell Viability Reagent.

alamarBlue HS Cell Viability Reagent is a complete add-and-read, non-toxic reagent that does not require cell lysis. The highly purified resazurin used for alamarBlue HS reagent results in a >50% decrease in background fluorescence and a >100% increase in the signal-to-background ratio. Since no lysis is required, the diluted alamarBlue HS solution can be removed and replaced with complete growth medium for further culturing of the cells. Similar to alamarBlue reagent, alamarBlue HS reagent displays an extended viability detection time window for a wide variety of organisms and thus can be used with various human and animal cell lines, bacteria, plant, and fungi, resulting in quantitative measurement of cell viability and proliferation.

LIVE/DEAD™ BacLight™ Bacterial Viability Kit, for microscopy & quantitative assays (Invitrogen™)

The LIVE/DEAD BacLight Bacterial Viability Kit *for microscopy and quantitative assays* is a convenient and easy-to-use kit for monitoring the viability of bacterial populations as a function of the membrane integrity of the cell. Cells with a compromised membrane that are considered to be dead or dying will stain red, whereas cells with an intact membrane will stain green.

View additional information about all microbiological analysis products.

LIVE/DEAD™ Yeast Viability Kit (Invitrogen™)

The LIVE/DEAD® Yeast Viability Kit combines a novel two-color fluorescent probe for yeast viability, FUN® 1, with a fluorescent fungal surface labeling reagent Calcofluor® White M2R. Plasma membrane integrity and metabolic function of fungi are required to convert the yellow-green-fluorescent intracellular staining of FUN® 1 into red-orange intravacuolar structures; Calcofluor White M2R labels cell-wall chitin with blue-fluorescence regardless of metabolic state.

CellROX™ Orange Flow Cytometry Assay Kit (Invitrogen™)

The CellROX™ Orange Flow Cytometry Assay Kit enables the flow cytometric detection of reactive oxygen species (ROS) in live cells. The kit includes the novel, fluorogenic CellROX™ Orange Reagent, as well as SYTOX™ Red Dead Cell Stain, N-acetyl cysteine (an antioxidant, for negative control), and tert-butyl hydroperoxide solution (TBHP, an inducer of ROS).

View a selection guide for all CellROX® Reagents and Kits.

The CellROX™ Orange Flow Cytometry Assay Kit features:

• Fluorogenic probe formulated for flow cytometry that is oxidized in the presence of ROS
• Multicolor compatibility—minimal overlap with fluorophores excited by other laser lines, allowing easy multiplexing with other reagents
• Simple protocol—cells can be stained in complete media or other appropriate buffer, no need for serum free media

The CellROX™ Orange Detection Reagent is cell-permeable and non-fluorescent or very weakly fluorescent while in the reduced state. Upon oxidation, the reagent exhibits a strong fluorogenic signal that has absorption/emission maxima of 545/565 nm and remains localized in the cytoplasm. When used together with the included SYTOX™ Red Dead Cell Stain, oxidatively stressed and nonstressed cells are reliably distinguished from dead cells by flow cytometry.

LIVE/DEAD™ Fixable Red Dead Cell Stain Kit, for 488 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Red Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a blue laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Bright signal—allows for easy distinction between live/dead cells in single channel

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Red Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Red Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Optimal brightness
The LIVE/DEAD™ Fixable Red stain was selected based on its fluorescent properties to provide a bright signal when excited with a yellow, green, or blue 488 nm laser. The red-fluorescent reactive dye has an excitation maximum of ~595 nm, making it ideal for use with the yellow laser, and an emission of ~615 nm, allowing collection in the 610 or 630 BP filter. LIVE/DEAD™ Fixable Red Dead Cell stain is also excited well with the blue 488 nm laser. Since live and dead cells can be discriminated using a single dye and a single channel of a flow cytometer, it is an ideal choice for multi-color experiments.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

Pierce™ LDH Cytotoxicity Assay Kit (Thermo Scientific™)

The Thermo Scientific Pierce LDH Cytotoxicity Assay Kit is a reliable colorimetric assay to quantitatively measure lactate dehydrogenase (LDH) released into the media from damaged cells as a biomarker for cellular cytotoxicity and cytolysis.

Features of the LDH Cytotoxicity Assay Kit:

Convenient—add-mix-read assay format for adherent and suspension cells
Colorimetric—quantitatively measures LDH release by formation of colored product
Robust—uses stable LDH enzyme activity as a cytotoxic marker
Flexible—ideal for high-throughput screening
Non-radioactive—safe alternative to 51Cr-release cytotoxicity assays

The Pierce LDH Cytotoxicity Assay Kit measures extracellular LDH in culture media using an enzymatic reaction that results in a red formazan product which can be measured spectrophotometrically. Lactate dehydrogenase (LDH) is a cytosolic enzyme that is is an indicator of cellular toxicity. The assay is ideal for high-throughput screening and provides a safe alternative to radioactive cytotoxicity assays.

Includes:
Kit contains substrate mix, assay buffer, 10X lysis buffer, stop solution, and LDH positive control

Requires:
Microplate reader capable of reading absorbance at 490nm and 680nm, flat-bottom clear 96-well plate compatible with spectrophotometer, multichannel pipette

Applications:
• Measure in vitro cytotoxicity mediated by chemicals, immune cells, or siRNA or microRNA
• Detect cytolysis in bioreactor or 3D tissue engineering applications

Lactate dehydrogenase (LDH) is a cytosolic enzyme present in many different types of cells. When the plasma membrane is damaged, LDH is released into cell culture media. The released LDH can be quantified by a coupled enzymatic reaction. First, LDH catalyzes the conversion of lactate to pyruvate via reduction of NAD+ to NADH. Second, diaphorase uses NADH to reduce a tetrazolium salt (INT) to a red formazan product. Therefore, the level of formazan formation is directly proportional to the amount of released LDH in the medium.

The assay is performed by transferring cell culture media from treated cells into a new microplate and adding the kit reagents. After incubation at room temperature for 30 minutes, reactions are stopped and LDH activity is determined by spectrophotometric absorbance at 490nm.

CellEvent™ Senescence Green Detection Kit (Invitrogen™)

The CellEvent Senescence Green Detection Kit consists of a fluorescent probe and optimized buffer that enable the image-based detection of senescent cells. The fluorescein-based probe contains two galactoside moieties, making it a target for β-galactosidase. Activation of β-galactosidase is commonly used as a biomarker for senescent cells. This hydrolase enzyme resides in lysosomes and converts β-galactosides into monosaccharides under acidic pH conditions. The enzymatically cleaved product is retained within the cell due to covalent binding of intracellular proteins and emits a fluorogenic signal that has absorption/emission maxima of 490/514 nm.

CellEvent Senescence Green Detection Kit features include:
• Reliable and quick fluorescent detection of senescent cells
• Greater sensitivity than traditional colorimetric x-gal
• Fluorescent signal is well retained and detected using standard Alexa Fluor 488/FITC filter sets
• Multiplex-enabled—fluorescent senescence probe can be multiplexed

Due to a limited replicative lifespan, normal cells enter cell cycle arrest, also known as cellular senescence. While in this senescent phase the cells remain metabolically active without undergoing cell death or division. They adopt a specific phenotypic that includes the appearance of multiple nuclei, increased vacuolization, expression of pH-dependent β-galactosidase, and morphological enlargement and extension. Senescence, through a variety of mechanisms, may play a role in tumor suppression, tumor progression, aging, and tissue repair.

Activation of β-galactosidase is commonly used as a biomarker for senescent cells. This hydrolase enzyme resides in lysosomes and converts β-galactosides into monosaccharides under acidic pH conditions. The activity is optimal at lysosomal pH 4, but conventional assays measure at pH 6. It has been shown that normalized β-galactosidase activity is twice as high in senescent cells as in pre-senescent cells regardless of the pH value used for testing.

A colorimetric substrate for β-galactosidase, 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (x-gal), has long been used to detect metabolic activity in cells in vitro. However, its use is limited due to inconsistent signal, length of assay, and inability to multiplex.

Therefore, we have developed a sensitive, fluorescent substrate for β-galactosidase that can be used for the detection of senescent cells. The CellEvent Senescence Green probe is a fluorescein-based reagent that contains two galactoside moieties, making it a specific target of β-galactosidase. The enzyme- cleaved product is retained within the cell due to covalent binding of intracellular proteins and emits a fluorogenic signal that has absorption/emission maxima of 490/514 nm.

The CellEvent Senescent Green Kit provides CellEvent Senescent Green probe and an optimized buffer for the detection of senescent cells in fixed samples. This probe can be multiplexed with other fluorescent reagents compatible with paraformaldehyde fixation.

LIVE/DEAD™ BacLight™ Bacterial Viability and Counting Kit, for flow cytometry (Invitrogen™)

The LIVE/DEAD™ BacLight™ Bacterial Viability and Counting Kit allows researchers to reliably distinguish and quantitate live and dead bacteria with the aid of a flow cytometer, even in a mixed population containing a range of bacterial types. This kit uses a mixture of two nucleic acid stains - green-fluorescent SYTO™ 9 dye and red-fluorescent propidium iodide - for viability determinations, and a calibrated suspension of microspheres for accurate sample volume measurements.

View additional information about all microbiology assays for flow cytometry.

LIVE/DEAD™ Fixable Green Dead Cell Stain Kit, for 488 nm excitation (Invitrogen™)

The LIVE/DEAD™ Fixable Green Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a blue laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability

• Robust—staining pattern is the same before and after fixation

• Bright signal—allows for easy distinction between live/dead cells in single channel

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Green Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Green Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Optimal brightness
The LIVE/DEAD™ Fixable Green stain was selected based on its fluorescent properties to provide a bright signal when excited with a blue 488 nm laser. The green-fluorescent reactive dye has an excitation maximum of ~495 nm making it ideal for use with the blue laser and an emission of ~520 nm allowing collection in the FITC channel. Since live and dead cells can be discriminated using a single dye and a single channel of a flow cytometer, it is an ideal choice for multi-color experiments.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

LIVE/DEAD™ Fixable Dead Cell Stain Sampler Kit (Invitrogen™)

LIVE/DEAD™ Fixable dead cell stains are used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. The stains in the sampler kit have been optimized and validated for use in flow cytometry.

• Stable—dyes are freeze-dried in separate vials to maintain stability
• Robust—staining pattern is the same before and after fixation
• Bright signal—allows for easy distinction between live/dead cells in single channel

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable dead cell stains in this sampler kit have been conveniently packaged in eight 40-test vials to help ensure the stability and performance of the dye over time. Amine-reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to use the vial completely once rehydrated or aliquot the solution and store at -80°C, avoiding freeze thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with formaldehyde or ethanol-based fixatives required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable dead cell stains are amine-reactive dyes that bind covalently to intracellular and extracellular amines, allowing the staining pattern to be preserved following formaldehyde fixation.

Optimal brightness
The LIVE/DEAD™ Fixable dead cell stains were selected based on their fluorescent properties to provide a bright signal when excited with the optimal lasers. Since live and dead cells can be discriminated using a single dye and a single channel of a flow cytometer, these dead cell stains are an ideal choice for multi-color experiments.

How it works
In cells with compromised membranes, the dead cell stain reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable dead cell stains are available in a wide variety of colors to meet your multi-color panel needs. The sampler kit provides one vial (40 assays) of each of the eight dead cell stains available.

Find the LIVE/DEAD™ Fixable Dead Cell Stain that fits your needs:

• For UV lasers: blue
• For violet lasers: aqua, violet, or yellow
• For blue lasers: green or red
• For red lasers: far-red or near-IR

LIVE/DEAD™ FungaLight™ Yeast Viability Kit, for flow cytometry (Invitrogen™)

The LIVE/DEAD® FungaLight™ Yeast Viability Kit enables researchers to easily, reliably and quantitatively distinguish live and dead yeast in minutes by flow cytometry. The kit contains solutions of the SYTO® 9 green-fluorescent nucleic acid stain and the red-fluorescent nucleic acid stain, propidium iodide. These stains differ both in their spectral characteristics and in their ability to penetrate healthy yeast cells. When used alone, the SYTO® 9 stain generally labels all yeast in a population - those with intact membranes and those with damaged membranes. In contrast, propidium iodide penetrates only yeast with damaged membranes, causing a reduction in the SYTO® 9 stain fluorescence by fluorescence resonance energy transfer (FRET) when both dyes are present. As a result, yeast with intact membranes stain fluorescent green, whereas yeast with damaged membranes stain fluorescent red.

LIVE/DEAD™ Reduced Biohazard Cell Viability Kit #1, green & red fluorescence (Invitrogen™)

The LIVE/DEAD Reduced Biohazard Cell Viability Kit #1 is a convenient and easy-to-use cell viability kit that is designed to reduce the risk associated with handling potential biohazards such as viral, bacterial or protozoan pathogens. The assay monitors viability as a function of the membrane integrity of the cell. Cells with a compromised membrane that are considered to be dead or dying will stain red, whereas cells with an intact membrane will stain green.

Tali™ Cell Cycle Kit (Invitrogen™)

The Tali® Cell Cycle Kit includes a ready-to-use reagent that, when used with the Tali® Image-Based Cytometer, provides a convenient and accurate determination of the percentage of cells in each phase of the cell cycle. This single-addition reagent is composed of propidium iodide (PI), RNase A, and Triton X-100.

The Tali® Cell Cycle Kit offers a simple workflow:

• The pre-mixed reagent can be stored at room temperature and used when your cells are ready
• Simply fix your cells, add the reagent, incubate, and visualize
• Cell cycle data can be analyzed on the Tali® instrument or exported as a .csv or .fcs file for analysis with various modeling software

Fluorescent detection of cellular DNA as a cell-cycle phase indicator
PI, a red fluorescent dye, binds to DNA by intercalating between the bases with the little or no sequence preference. Consequently, the degree of fluorescence is proportional to the amount of cellular DNA, which itself is indicative of cell cycle phase (as cells progress through the cell cycle, the amount of DNA ultimately doubles). PI will also label RNA, so the addition of RNase A is necessary for accurate determination of the percentage of cells in each phase of the cell cycle.

After fixing your cells, simply add the optimized Tali® Cell Cycle reagent, incubate for 30 minutes in the dark, and then analyze on the Tali® Image-Based Cytometer. The cell cycle data from the Tali® Image-Based Cytometer can be analyzed on the instrument or exported in either .csv or .fcs format, and analyzed using cell cycle modeling software (such as ModFit or MultiCycle).