Shop All Apoptosis Kits

Click-iT™ TUNEL Alexa Fluor™ 488 Imaging Assay, for microscopy & HCS (Invitrogen™)

The Click-iT® TUNEL Alexa Fluor® 488 Imaging Assay utilizes a dUTP modified with an alkyne, a small, bio-orthogonal functional group that enables the nucleotide to be more readily incorporated by TdT than other modified nucleotides, including BrdUTP, biotin-dUTP or fluorescein-dUTP. Detection is based on a click reaction, a copper (I) catalyzed reaction between an azide and alkyne. Click chemistry fills the void when methods such as direct labeling or the use of antibodies are not efficient. The small size of the detection reagent, an Alexa Fluor® azide (MW <~1000) compared to that of an antibody (MW ~150,000) enables facile penetration of complex samples with only mild fixation and permeabilization required.

Compared to other assays using one of the other modified nucleotides, the Click-iT® TUNEL assay is able to detect a higher percentage of apoptotic cells under identical conditions. The assay is also fast and is complete within 2 hours. Furthermore, the Click-iT® TUNEL assay allows multiplexing with surface and intracellular biomarker detection.

More tools for apoptosis detection and measurement >

Click-iT™ TUNEL Alexa Fluor™ 647 Imaging Assay, for microscopy & HCS (Invitrogen™)

The Click-iT® TUNEL Alexa Fluor® 647 Imaging Assay utilizes a dUTP modified with an alkyne, a small, bio-orthogonal functional group that enables the nucleotide to be more readily incorporated by TdT than other modified nucleotides, including BrdUTP, biotin-dUTP or fluorescein-dUTP. Detection is based on a click reaction, a copper (I) catalyzed reaction between an azide and alkyne. Click chemistry fills the void when methods such as direct labeling or the use of antibodies are not efficient. The small size of the detection reagent, an Alexa Fluor® azide (MW <~1000) compared to that of an antibody (MW ~150,000) enables facile penetration of complex samples with only mild fixation and permeabilization required.

Compared to other assays using one of the other modified nucleotides, the Click-iT® TUNEL assay is able to detect a higher percentage of apoptotic cells under identical conditions. The assay is also fast and is complete within 2 hours. Furthermore, the Click-iT® TUNEL assay allows multiplexing with surface and intracellular biomarker detection.

More tools for apoptosis detection and measurement >

eBioscience™ Annexin V-Biotin Apoptosis Detection Kit (Invitrogen™)

Annexins are a family of calcium-dependent phospholipid-binding proteins, which bind to phosphatidylserine (PS) to identify apoptotic cells. In healthy cells, PS is predominantly located along the cytosolic side of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution in the phospholipid bilayer and translocates to the extracellular membrane, which is detectable with fluorescently labeled Annexin V. In early stages of apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI) and 7-AAD, therefore cells which display only Annexin V staining (PI/7-AAD negative) are in early stages of apoptosis. During late-stage apoptosis, loss of cell membrane integrity allows Annexin V binding to cytosolic PS, as well as cell uptake of PI and 7-AAD. Annexin V staining, paired with 7-AAD or PI is widely used to identify apoptotic stages by flow cytometry.

Host
E.coli

Conjugate
Biotin

Purity
> 98% pure

Molecular Mass
35.8 kDa

Reported Application
Flow Cytometric Analysis

eBioscience™ Annexin V Apoptosis Detection Kit FITC (Invitrogen™)

Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner.

In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD, or Fixable Viability Dyes such as eFluor™ 660 or eFluor™ 780. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative).

Note: Fixable Viability Dye eFluor™ 450 is not recommended for use with Annexin V Apoptosis Detection Kits.

Reported Application
Flow Cytometric Analysis

CellEvent™ Caspase-3/7 Green Flow Cytometry Assay Kit (Invitrogen™)

The CellEvent™ Caspase-3/7 Green Flow Cytometry Assay Kit enables the flow cytometric detection of activated caspase-3 and caspase-7 in apoptotic cells. The kit includes the novel fluorogenic substrate CellEvent® Caspase-3/7 Green Detection Reagent, as well as SYTOX® AADvanced™ Dead Cell Stain.

• Caspase-3/7 specific—includes the recognition sequence for activated caspase-3 and caspase-7
• Easy identification—clearly identify live, dead, and apoptotic cell populations
• Quick analysis—washing and fixation is not required
• Multicolor compatibility—combine with other dyes excitable by the 488 nm laser or other lasers

View a selection guide for all apoptosis assays for flow cytometry

CellEvent® Caspase-3/7 Green Detection Reagent is a cell-permeant reagent that consists of a four-amino acid peptide (DEVD) conjugated to a nucleic acid-binding dye. During apoptosis, caspase-3 and caspase-7 proteins are activated and able to cleave the caspase 3/7 recognition sequence encoded in the DEVD peptide. Cleavage of the recognition sequence and binding of DNA by the reagent labels the apoptotic cells with a bright, fluorogenic signal that has absorption/emission maxima of ~511/533 nm. When used together with the SYTOX® AADvanced™ Dead Cell Stain, apoptotic cells can be easiliy discriminated from live and necrotic cells.

Because no single parameter defines apoptosis in all systems, we strongly suggest using a combination of different measurements for reliable detection of apoptosis. For more information, see Apoptosis Reagents in Flow Cytometry.

CaspGLOW™ Fluorescein Active Caspase Staining Kit (Invitrogen™)

The CaspGLOW™ Fluorescein Active Staining Kit contains the reagents to sensitively detect active caspases in mammalian cells. This assay utilizes the inhibitor specific for all caspases, Z-VAD-FMK, that is directly conjugated to FITC (fluorescein isothiocyanate) for the detection system. This reagent is cell permeable, non-toxic and irreversibly binds to the active enzyme. Detection of the labeled cells can be determined by flow cytometry, fluorescent microscopy or a fluorescent plate reader.

The Caspases are a family of aspartate-specific cysteine proteases that act in a step-wise signaling manner like kinases. Recruitment of these proteases to oligomerized receptors leads to activation and autoproteolytic cleavage. Active caspases can proteolyze additional caspases generating a caspase cascade. The final outcome of this signaling pathway is a form of controlled cell death, termed apoptosis.

Reported Application
Flow Cytometric Analysis, Immunocytochemistry

eBioscience™ Annexin V Apoptosis Detection Kit PE (Invitrogen™)

Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner.

In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD, or Fixable Viability Dyes such as eFluor™ 660 or eFluor™ 780. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative).

Note: Fixable Viability Dye eFluor™ 450 is not recommended for use with Annexin V Apoptosis Detection Kits.

Reported Application
Flow Cytometric Analysis

eBioscience™ Annexin V Apoptosis Detection Kit PerCP-eFluor™ 710 (Invitrogen™)

Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS) in all mammalian species. Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner.

In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD, or Fixable Viability Dyes such as eFluor™ 660 or eFluor™ 780. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative).

Due to the emission spectrum of PerCP-eFluor™ 710, the Annexin V Apoptosis Detection Kit PerCP-eFluor™ 710 is not compatible with propidium iodide and 7-AAD. It is recommended to substitute a Fixable Viability Dye such as eFluor™ 660 or eFluor™ 780 in their place.

Not included:
Fixable Viability Dye eFluor™ 660 (cat. 65-0864)
Fixable Viability Dye eFluor™ 780 (cat. 65-0865)

Note: Fixable Viability Dye eFluor™ 450 is not recommended for use with Annexin V Apoptosis Detection Kits.

Reported Application
Flow Cytometric Analysis

Click-iT™ Plus TUNEL Assay for In Situ Apoptosis Detection, Alexa Fluor™ 594 dye (Invitrogen™)

The Click-iT® Plus TUNEL assay detects apoptotic cells in tissue and cultured cell samples through the use of a small, highly specific labeling moiety and a bright fluorescent dye. After incorporation of the labeling moiety into DNA fragments, detection is achieved through a catalyzed “click” reaction using conditions mild enough to preserve the fluorescent signal from GFP or RFP.

More tools for apoptosis detection and measurement >

• Optimized for the detection of apoptotic cells in either tissue or cell samples
• Multiplex enabled—optimized to work with fluorescent dyes or proteins such as GFP and RFP
• Improved TUNEL assay—better label incorporation due to small reactive moiety
• Bright apoptotic signal—uses Alexa Fluor® dyes, resulting in a stable, non-photobleaching fluorescent signal
• Flexibility—the assay can be configured to test from 1 to 50 samples at a time

Fragmentation of cellular DNA is a hallmark of apoptosis. The TUNEL assay is the most widely used method to detect fragmented DNA in apoptotic cells in tissue samples. The TUNEL assay begins with incorporation of modified dUTP at the 3’-OH end of the fragmented DNA. The dUTP modification is often the addition of a fluorophore. And due to the size of the fluorophore, the modified dUTP can display lower than expected incorporation rates. These lower incorporation rates can affect the sensitivity of the TUNEL assay. Additionally, the fluorophores used in currently available TUNEL assays suffer from photobleaching and fluorescent spectral overlap issues, both of which reduce sensitivity and ability to multiplex the assay.

The Click-iT® Plus TUNEL assay was developed to address these issues. The assay uses dUTP modified with an alkyne group (a small bio-orthogonal functional group) that allows the nucleotide to be more readily incorporated. After incorporation, a highly specific click reaction between the alkyne group and an Alexa Fluor® picolyl azide fluorescent dye, and subsequent detection of that dye, results in a sensitive and specific assay for the detection of apoptotic cells. Because of the gentle reaction conditions, the Click-iT® Plus TUNEL assay enables multiplexing with fluorescent proteins or dyes.

The Click-iT® Plus TUNEL assay has been validated with several different formalin-fixed paraffin-embedded tissue types. In all cases the ability to multiplex with fluorescent proteins and dyes was preserved. Additionally, the ability to stain actin using fluorescent-labeled phalloidin was also preserved.

The Click-iT® Plus TUNEL assay contains all of the reagents needed to detect apoptotic cells from either tissue or cell samples. The reagents supplied in this kit can be used to test 50 samples and can be configured to test from 1 to 50 samples at a time.

eBioscience™ Annexin V Apoptosis Detection Kit eFluor™ 450 (Invitrogen™)

Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner.

In early-stage apoptosis, the plasma membrane excludes viability dyes such as propidium iodide (PI), 7-AAD, or Fixable Viability Dyes such as eFluor™ 660 or eFluor™ 780. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative).

Reported Application
Flow Cytometric Analysis

CellEvent™ Caspase-3/7 Green Detection Reagent (Invitrogen™)

CellEvent™ Caspase-3/7 Green Detection Reagent is a novel fluorogenic substrate for activated caspase-3/7 that is compatible with both live cell and fixed imaging, with absorption/emission maxima of ~502/530 nm. Activation of caspase-3 is an essential event during apoptosis, making this an optimized reagent for analysis of apoptotic cells.

See more tools for detection of apoptotic cells >

• Optimized caspase-3/7 substrate for apoptosis analysis
• Easy to use—add and read; no cell lysis required
• Use for time course measurements; easily select the time point of interest
• Compatible with both live cell fluorescence-imaging and formaldehyde-based fixation methods
• Multiplex enabled—combine with other fluorescent reagents to confirm apoptosis in the same cell or cell population

Substrate specifics
CellEvent Caspase-3/7 Green Detection Reagent is a four-amino acid peptide (DEVD) conjugated to a nucleic acid-binding dye with absorption/emission maxima of ~502/530 nm. The DEVD peptide sequence is a cleavage site for caspase-3/7, and the conjugated dye is non-fluorescent until cleaved from the peptide and bound to DNA.

Principles of action
CellEvent Caspase-3/7 Green Detection Reagent is intrinsically non-fluorescent as the DEVD peptide inhibits the ability of the dye to bind to DNA. However, after activation of caspase-3/7 in apoptotic cells, the DEVD peptide is cleaved, enabling the dye to bind to DNA and produce a bright, fluorogenic response. The fluorescent emission of the dye when bound to DNA is ~530 nm and can be observed using a standard FITC filter set.

Simple three-step protocol
To use CellEvent Caspase 3/7 Detection Reagent, simply add it to cells, incubate 30 minutes, and visualize (see figure). Apoptotic cells with activated caspase-3/7 will have bright green nuclei, while cells without activated caspase 3/7 will have minimal fluorescent signal (see figure).

Assay versatility allows for live cell detection and fixation
This robust assay enables the examination of caspase-3/7 activation in live cells. Furthermore, since wash steps are not necessary for detection, fragile apoptotic cells typically lost during wash steps are preserved. Importantly, the fluorescent signal from CellEvent Caspase 3/7 Detection Reagent can survive fixation and permeabilization. This allows for the flexibility to perform end-point assays and probe for other proteins of interest using immunocytochemistry.

CaspGLOW™ Fluorescein Active Caspase-8 Staining Kit (Invitrogen™)

The CaspGLOW™ Fluorescein Active Caspase-8 Staining Kit contains all the reagents necessary to detect active caspase-8 in cells with high sensitivity. Fluorescein (FITC)-conjugated IETD-FMK, a specific inhibitor of caspase-8, is utilized in this assay for detection. This reagent is cell permeable, non-toxic and irreversibly binds to the active enzyme. Detection of the labeled cells can be determined by flow cytometry, fluorescent microscopy or a fluorescent plate reader.

The caspases constitute a family of aspartate-specific cysteine proteases that mediate a sequence of cleavage events. Recruitment of the inactive proenzyme to oligomerized receptors leads to caspase activation and autoproteolytic cleavage. These active enzymes can then cleave other caspases, thereby generating a caspase signaling cascade that leads to a form of programmed cell death termed apoptosis.

Caspase-8, which is also known as FLICE, MACHalpha1, and Mch5, cleaves its substrates at the C-terminal aspartic acid residue of the motif Asp-X-X-Asp. Eight isoforms of caspase-8 exist, of which caspase-8/a and 8/b are the predominant forms. Upon stimulation of death receptors such as CD95/APO-1/Fas, TRAIL-R1, TRAIL-R2, TNFR1, and TRAMP, caspase-8 is recruited to the death-inducing signaling complex (DISC). Subsequent dimerization leads to caspase-8 activation via autocatalytic cleavage, which leads to the formation of a 12-kDa prodomain and a 43-kDa intermediate fragment that is further cleaved to produce 26-kDa and 18-kDa active enzymes. As an initiator caspase, this enzyme initiates a caspase signaling cascade that results in apoptosis. Substrates of caspase-8 include caspases-3 and -7, as well as the pro-apoptotic Bcl-2 family member Bid. In addition to its role in cell death, caspase-8 has been linked to cell adhesion and motility.

Reported Application
Flow Cytometric Analysis, Immunocytochemistry

Image-iT™ LIVE Green Caspase-3 and -7 Detection Kit, for microscopy (Invitrogen™)

The Image-iT™ LIVE Green Caspase-3 and -7 Detection Kit employs a novel approach to detect active caspases that is based on a fluorescent inhibitor of caspases (FLICA™) methodology, essentially an affinity label. The reagent associates a fluoromethyl ketone (FMK) moiety, which can react covalently with a cysteine, with a caspase-specific amine acid sequence. For caspase-3 and -7, this recognition sequence is aspartic acid-glutamic acid-valine-aspartic acid (DEVD). A fluorescein group is attached as a reporter. The FLICA reagent is thought to interact with the enzymatic reactive center of an activated caspase via the recognition sequence, and then to attach covalently through the FMK moiety. The FLICA inhibitor is cell permeant and noncytotoxic. Unbound FLICA molecules diffuse out of the cell and are washed away; the remaining green-fluorescent signal is a direct measure of the amount of active caspase that was present at the time the inhibitor was added.

Vybrant™ FAM Poly Caspases Assay Kit, for flow cytometry (Invitrogen™)

The Vybrant™ FAM Poly Caspases Assay Kit employs a novel approach to detect active caspases that is based on a fluorescent inhibitor of caspases (FLICA™) methodology, essentially an affinity label. The reagent associates a fluoromethyl ketone (FMK) moiety, which can react covalently with a cysteine, with a caspase-specific amine acid sequence. For poly caspases, this recognition sequence is valine-alanine-aspartic acid (VAD). A fluorescein group is attached as a reporter. The FLICA reagent is thought to interact with the enzymatic reactive center of an activated caspase via the recognition sequence, and then to attach covalently through the FMK moiety. The FLICA inhibitor is cell permeant and noncytotoxic. Unbound FLICA molecules diffuse out of the cell and are washed away; the remaining green-fluorescent signal is a direct measure of the amount of active caspase that was present at the time the inhibitor was added. This kit includes the FAM-VAD-FMK FLICA reagent, Hoechst 33342 stain, and propidium iodide stain, which allows the simultaneous evaluation of caspase activation, membrane permeability, and cell cycle by flow cytometry.

View a selection guide for all apoptosis assays for flow cytometry.

Vybrant™ Apoptosis Assay Kit #5, Hoechst 33342/Propidium Iodide (Invitrogen™)

The Vybrant Apoptosis Assay Kit #5 provides a rapid and convenient assay for apoptosis based on fluorescence detection of the compacted state of the chromatin in apoptotic cells. This kit contains ready-to-use solutions of blue-fluorescent Hoechst 33342 dye, which stains the condensed chromatin of apoptotic cells more brightly than the chromatin of nonapoptotic cells, and red-fluorescent propidium iodide dye, which stains dead cells.