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Violet Ratiometric Membrane Asymmetry Probe/Dead Cell Apoptosis Kit, for flow cytometry (Invitrogen™)

The Violet Ratiometric Membrane Asymmetry Probe/Dead Cell Apoptosis Kit provides a simple and fast method for the detection of apoptosis with dead cell discrimination by flow cytometry. The Violet Ratiometric Membrane Asymmetry Probe, 4'-N,N-diethylamino-6-(N,N,N-dodecyl-methylamino-sulfopropyl)-methyl-3-hydroxyflavone (F2N12S), is a novel violet excitable dye for the detection of membrane asymmetry changes during apoptosis. The dye exhibits an excited-state intramolecular proton transfer (ESIPT) reaction resulting in a dual fluorescence with two emission bands corresponding to 530 nm and 585 nm, producing a two-color ratiometric response to variations in surface charge. Ratiometric probes have several advantages over traditional fluorochrome labeled reagents. The ratiometric probe is a self-calibrating absolute parameter of apoptotic transformation, which is independent of probe concentration, cell size, and instrument variation, such as fluctuations of laser intensity or sensitivity of the detectors. Given that apoptosis modifies the surface charge of the outer leaflet of the plasma membrane the violet membrane asymmetry probe F2N12S can monitor changes in membrane asymmetry that occur during apoptosis through a change in the relative intensity of the two emission bands of the dye. The F2N12S probe is combined with SYTOX(R) AADvanced dead cell stain, which is capable of passing through the cell membrane only in late apoptotic or necrotic cells allowing discrimination form early apoptotic cells. Samples can be analyzed after a 5 minute incubation at room temperature and does not require special buffers or wash steps. This kit can be paired with other reagents such as MitoProbe™ DiIC1(5) or annexin V for multiparametric analysis of apoptosis and viability. This reagent kit allow researchers to maximaize the utility of their instruments by utilizing the violet laser Each kit contains sufficient reagents for ~100 flow cytometry tests.

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

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.

CellTrace™ Blue Cell Proliferation Kit, for flow cytometry (Invitrogen™)

The CellTrace Blue Cell Proliferation Kit is used for in vitro and in vivo labeling of cells to trace multiple generations using dye dilution by flow cytometry. The CellTrace Blue reagent is specifically designed for excitation by a UV laser (at 355 nm or 375 nm), and it can be easily multiplexed with reagents and antibodies excited by other commonly used lasers.

• Superior performance—bright, single-peak staining enables visualization of multiple generations
• Long-term signal stability—well-retained in cells for several days post stain
• Versatile—multiple colors available to easily combine with antibodies or markers of cell function, such as GFP
• Simple, robust staining protocol

View a selection guide for all CellTrace Cell Proliferation Kits for flow cytometry.

Superior fluorescent staining
Successful proliferation analysis by dye dilution (see figure below) requires an extremely bright dye to distinguish fluorescently labeled cells from auto-fluorescence after several cell divisions. The intense fluorescent staining provided by CellTrace Blue dye enables the visualization of five or more generations of proliferating cells before the signal is overwhelmed by intrinsic cellular auto-fluorescence. Consistent, homogeneous staining results in very little fluorescence variation between cells in a population, so distinct generations can be seen without any requirement for complex modeling software.The recommended working concentration for peripheral blood mononuclear cells is 5–10 µM. However, as with all reagents used in flow cytometry, to achieve optimal signal, reagent titration is highly recommended.

Long-term signal retention
Unlike stains that label the lipid membrane of cells, CellTrace Blue stain easily crosses the plasma membrane and covalently binds inside cells where the stable, well-retained fluorescent dye provides a consistent signal, even after several days in a cell culture environment. CellTrace Blue dye binds covalently to all free amines on the surface and inside of cells and shows little cytotoxicity, with minimal observed effect on the proliferative ability or biology of cells.

Easy multiplexing with other fluorophores
The UV excitation and narrow emission of CellTrace Blue dye make it ideal for multiplexing as it lies outside the spectral emission profiles of most other dyes and fluorescent proteins.

Simple, robust staining protocol
The CellTrace Blue Cell Proliferation Kit contains convenient single-use vials of dry dye to permit small-scale experiments without preparing excess quantities of dye. A stock solution is prepared by dissolving the contents of a vial in anhydrous DMSO prior to use. To stain 1 mL of cells in protein-free medium, 1 µL of this stock solution is typically used. Cells should be stained for 20 minutes at room temperature with gentle agitation. A brief wash with complete medium will then quench any dye remaining in solution.

ReadyProbes™ Cell Viability Imaging Kit, Blue/Red (Invitrogen™)

ReadyProbes® Cell Viability Imaging Kit (Blue/Red) is a ready-to-use kit that can quickly and easily determine the viability of cells. Just add 2 drops each of room temperature, stable NucBlue® Live reagent (Hoechst 33342) and propidium iodide to 1 mL of cell growth media, then determine viability by counting total vs dead cells. NucBlue® Live reagent stains the nuclei of all the cells and can be detected using a standard DAPI filter. Propidium iodide stains only the nuclei of cells with compromised plasma membrane integrity and is detected with a standard TRITC/RFP (orange) filter set. This kit is appropriate for fluorescence microscopy, fluorescence micro plate readers, and flow cytometry.

NucBlue® Live reagent: stains the nuclei of all cells; detected with a standard DAPI filter (excitation/emission maxima: 360/460 nm)
Propidium iodide: stains the nuclei of dead cells with compromised plasma membrane; detected with standard TRITC/RFP (orange) filter set (excitation/emission maxima: 535/617 nm)
See other ReadyProbes® reagents for cell staining
Learn more about other assays for cell viability

Suggestions for use
• NucBlue® Live reagent and propidium iodide can be added directly to cells in full growth media or a compatible buffer solution.
• In most cases, 2 drops/mL and an incubation time of 5 to 30 minutes will give bright nuclear staining; however, optimization may be needed for some cell types, conditions, and applications. In such cases, simply add more or fewer drops until the optimal staining intensity is obtained.

Click-iT™ EdU Cell Proliferation Kit for Imaging, Alexa Fluor™ 647 dye (Invitrogen™)

The Click-iT EdU Cell Proliferation Kit for Imaging is a superior alternative to traditional proliferation assays that is optimized for fluorescence microscopy applications. In this assay the modified thymidine analogue EdU is efficiently incorporated into newly synthesized DNA and fluorescently labeled with a bright, photostable Alexa Fluor® dye in a fast, highly-specific click reaction. This fluorescent labeling of proliferating cells is accurate and compatible with antibody methods due to the mild click protocol.

• Simple—works the first time, every time, in less time
• Efficient—no denaturation steps or harsh treatment required
• Content-rich results—better preservation of cell morphology, antigen structure, and DNA integrity
• Consistent—not dependent on variable antibody lots for detection

The most accurate proliferation-detection methods are based on the incorporation and measurement of nucleoside analogues in newly synthesized DNA, with bromodeoxyuridine (BrdU) a commonly used analogue. BrdU-labeled DNA is quantitated using anti-BrdU antibodies following DNA denaturation by harsh methods (HCl, heat, or enzymes) to expose the BrdU molecules. This step is time consuming and difficult to perform consistently. The harsh treatment can also adversely effect sample integrity and quality, which makes co-staining with other antibodies challenging.

Superior Proliferation Methodology
The Click-iT EdU Cell Proliferation Kit for Imaging provides a superior alternative to BrdU assays for measuring cell proliferation. EdU (5-ethynyl-2'-deoxyuridine) is a nucleoside analog of thymidine and is incorporated into DNA during active DNA synthesis. With Click-iT® EdU, mild fixation and detergent permeabilization is sufficient for the small molecule-based Click-iT® EdU detection reagent to gain access to the DNA. As a consequence, the Click-iT® EdU imaging kit is not only easy to use, but more accurate and compatible with cell cycle analysis and other intracellular or extracellular targets for truly content-rich results.

This kit is optimized for fluorescence microscopy applications; visit the Click-iT® technology area of our website for kits designed for high-content imaging, fluorescence microplate, or flow cytometry platforms.

Learn more about Click-iT technology >
Find more tools for image-based detection of proliferating cells >

Notes:
The Click-iT® assay can be used on cells in culture or in vivo following EdU administration by feeding or injection methods.
The Click-iT® assay can be used with BrdU in dual pulse experiments by using the anti-BrdU (clone MoBu-1) antibody, which does not cross react with EdU.
The Click-iT® technology is compatible with immunohistochemical, immunocytochemical, and fluorescent dyes that are fixation tolerant or designed for fixed cell labeling.

Click-iT™ TUNEL Colorimetric IHC Detection Kit (Invitrogen™)

The Click-iT™ TUNEL Colorimetric IHC Detection Kit is used to identify apoptotic cells in tissue and cultured cell samples through the use of a small, highly specific labeling moiety and streptavidin-peroxidase conjugation. After incorporation of the labeling moiety into sites of DNA fragmentation, detection is achieved through a catalyzed "click" reaction that adds a biotin group at these sites. The subsequent addition of a streptavidin-peroxidase and peroxidase substrate results in a dark brown signal that can be detected with light microscopy and stored for future analysis.

Find more tools for image-based detection of apoptotic cells >

• Optimized for the detection of apoptotic cells in either tissue or cell samples
• Improved colorimetric TUNEL assay—better label incorporation due to small reactive moiety
• Increased sensitivity—specific label incorporation results in lower background and brighter signal
• Content-rich results—cell morphology, cellular environment, and apoptotic signal are clearly visible
• Flexibility—the assay can be configured for 50 independent TUNEL apoptosis tests

The later stages of apoptosis are characterized by changes in nuclear morphology, chromatin condensation, nuclear envelope degradation, and DNA fragmentation. Terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL) assays are based on the incorporation of modified dUTPs by terminal deoxynucleotidyl transferase (TdT) at the 3’-OH ends of fragmented DNA. Colorimetric TUNEL assays utilize dUTPs conjugated with a biotin moiety, followed by the addition of a streptavidin-peroxidase conjugate and peroxidase substrate, resulting in a dark brown apoptotic signal. However, colorimetric TUNEL assays are prone to high background, which reduces the sensitivity and specificity of the signal.

The Click-iT TUNEL Colorimetric IHC Detection Kit was developed to address these issues by utilizing a dUTP modified with an alkyne group (a small bio-orthogonal functional group) that enables the nucleotide to be more readily incorporated by TdT. After incorporation, a highly specific click reaction covalently links biotin azide and the alkyne group. Streptavidin-peroxidase (horseradish peroxidase) followed by peroxidase substrate (DAB) are added, allowing colorimetric detection of apoptotic cells. The high degree of labeling specificity inherent in the click technology results in low background and improved detection of apoptotic cells.

The Click-iT TUNEL Colorimetric IHC Detection Kit has been optimized and contains all of the reagents needed for detection of apoptotic cells from either tissue or cell samples. The reagents supplied in this kit can be used to test 50 samples and configured to test from one to 50 samples at a time.

eBioscience™ Mouse Regulatory T Cell Staining Kit #1 (Invitrogen™)

The FJK-16s antibody reacts with mouse/rat Foxp3 also known as FORKHEAD BOX P3, SCURFIN, and JM2; cross reactivity of this antibody to other proteins has not been determined. Foxp3 a 49-55 kDa protein, is a member of the forkhead/winged-helix family of transcriptional regulators, and was identified as the gene defective in ‘scurfy’ (sf) mice. Constitutive high expression of Foxp3 mRNA has been shown in CD4+CD25+ regulatory T cells (Treg cells), and ectopic expression of Foxp3 in CD4+CD25- cells imparts a Treg phenotype in these cells.

Immunoblotting with FJK-16s antibody has mapped the epitope to amino acids 75-125 of the mouse Foxp3 protein. In the human, this region has been shown to be alternatively spliced at the mRNA level. Both the alternatively-spliced and non-spliced isoforms are present in the CD4+CD25+ subset of lymphocytes. Preliminary RT-PCR experiments have not revealed this alternatively-spliced isoform in mouse splenocytes, suggesting different gene regulation in the mouse and human.

Intracellular staining of mouse splenocytes with FJK-16s using the mouse Foxp3 staining sets and protocol reveals approximately 2% of total splenocytes in the C57Bl/6 strain and approximately 3-5% in the BALB/c mouse strain. Multicolor flow cytometric analysis demonstrates approximately 90% of the CD4+CD25+ cells and 4% of the CD4+CD25- cells staining with FJK-16s. B220+, CD11b+, CD11c+, and Ly6G/Gr-1+ cells do not show significant co-staining with FJK-16s. These data are consistent with a recent report which follows expression of Foxp3 using a GFP knock-in (Fontenot et al, 2005).

FJK-16s cross-reacts with rat Foxp3 This has been demonstrated by intracellular staining of Foxp3 and flow cytometry of rat splenocytes using the same method and reagents as used for mouse tissue. Please note that the CD4 and CD25 antibodies included in this kit only recognize the mouse antigens. For staining rat tissue, please use (CD4 FITC cat. 11-0040 and CD25 APC cat. 17-0390)

The anti-mouse Foxp3 Staining Set has been formulated and optimized for the staining of mouse splenocytes with the FJK-16s monoclonal antibody

Not included:
Isotype controls for anti-CD4 (rat IgG2a, cat. 11-4321) and anti-CD25 (rat IgG1, cat. 17-4301)

Host
Rat

Isotype
IgG2a

Reactivity/Species
Mouse

Reported Application
Intracellular Staining Followed by Flow Cytometric Analysis

Escherichia coli (K-12 strain) BioParticles™, Texas Red™ conjugate (Invitrogen™)

The Molecular Probes® BioParticles® product line consists of a series of fluorescently labeled, heat- or chemically killed bacteria and yeast in a variety of sizes, shapes, and natural antigenicities. These fluorescent BioParticles® products have been employed to study phagocytosis by fluorescence microscopy, quantitative spectrofluorometry, and flow cytometry.

We offer E. coli (K-12 strain), S. aureus (Wood strain, without protein A) and zymosan (S. cerevisiae) BioParticles® conjugates covalently labeled with a variety of different fluorophores (special care has been taken to remove free dye after conjugation). Unlike the fluorescence of fluorescein-labeled BioParticles® conjugates, which is partially quenched in acidic environments, the fluorescence of the Alexa Fluor®, BODIPY® FL, tetramethylrhodamine and Texas Red® dye conjugates is uniformly intense over the pH range from 3 to 10.

BioParticles Specifications:
• Label (Ex/Em): Texas Red® (~595/615 nm)
• Particle: E. coli (K-12 strain)
Opsonizing reagent available


Using BioParticles Products
BioParticles® conjugates are provided as lyophilized powders. There are approximately 3 x 108 E. coli or S. aureus particles per mg solid and approximately 2 x 107 zymosan particles per mg solid. BioParticles® conjugates can be reconstituted in the buffer of your choice for use in phagocytosis assays. The fluorescence of BioParticles® conjugates that are bound to the surface of the cell (but not internalized) can be quenched by ethidium bromide, trypan blue, or other quenchers. In addition to cellular applications, fluorescent BioParticles® conjugates may be effective as flow cytometry calibration references when sorting bacteria and yeast mutants. These small particles may also be useful references for light scattering studies because their sizes and shapes differ in characteristic ways.

Find More BioParticles® Products
We offer a large range of dye-labeled and unlabeled E. coli (K-12 strain), S. aureus (Wood strain, without protein A), and zymosan (S. cerevisiae) BioParticles® products. Find out about these products and their applications by reviewing Probes for Following Receptor Binding and Phagocytosis—Section 16.1 in the Molecular Probes® Handbook.

For pH-sensitive endocytosis assays, see our pHrodo™ BioParticles® conjugates.

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

Arcturus™ Paradise™ PLUS qRT-PCR Kit, no solvents (Applied Biosystems™)

The ARCTURUS® Paradise® PLUS Reagent System enables unprecedented gene expression analysis of millions of previously inaccessible samples. The Paradise® PLUS Reagent System is an integrated solution for gene expression studies from formalin-fixed, paraffin-embedded (FFPE) tissues, including reagents for tissue staining, RNA isolation and RNA amplification.

Key product features:
• Accelerated discovery process – unlock the tissue archives to access previously inaccessible samples
• Streamlined application – integrate seamlessly into current workflow
• Efficient workflow – secure downstream success with the Paradise® QC Kit
• Comprehensive system – benefit from the only complete system for formalin-fixed samples

Unlock the Tissue Archives
Currently, tens of millions of tissue samples with known outcomes are available in tissue archives. The Paradise® PLUS Reagent system enables microarray and qRT-PCR analysis of these previously inaccessible samples, allowing retrospective studies to accelerate discoveries. Achieve unprecedented results in just six steps (Figure 1).

Integrate Seamlessly into Current Workflow
The Paradise® PLUS Reagent System is compatible with all major gene expression platforms. Robust and reproducible results are achieved using tools and techniques commonly employed in today’s research laboratories.

Secure Downstream Success with the Paradise® QC Kit
Not all FFPE samples contain high quality RNA. Identify the best samples for your studies using a simple, real-time PCR research technique, and then proceed with confidence using these pre-qualified samples.

Benefit from the Only Complete System for Formalin-fixed Samples
The Paradise® PLUS Reagent System is the only available solution that provides all the components necessary to prepare RNA from formalin-fixed, paraffin-embedded tissue samples for gene expression analysis. To ensure successful gene expression results, the system includes reagents optimized for exceptional recovery of RNA and superior reverse transcription and RNA amplification (Figure 3).

Integrated Systems for Microgenomics
The Paradise® PLUS Reagent System is validated as part of ARCTURUS®' complete Systems for Microgenomics®, an integrated solution for utilizing small quantities of RNA for gene expression analysis, and features the ARCTURUSXT Laser Capture Microdissection (LCM) Instrument to procure pure cell populations. ARCTURUS®' Systems for Microgenomics enable accurate and sensitive microarray assays that reveal molecules otherwise obscured in whole tissue samples or cell mixtures.

For Research Use Only. Not for use in diagnostics procedures.

pHrodo™ Green Zymosan Bioparticles™ Conjugate for Phagocytosis (Invitrogen™)

New pH-sensitive pHrodo® Green dye conjugates, like our pHrodo® Red dye conjugates, give faster and more accurate results than any other phagocytosis assay. pHrodo® Green conjugates are non-fluorescent outside the cell at neutral pH, but fluoresce brightly green at acidic pH such as in phagosomes. Get faster staining and more accurate results—without the need for wash steps or quencher dye.

• Specific detection of phagocytosis and endocytosis
• Reduced signal variability and improved timing in sensitive experiments
• Enough to do 100 tests when using 100 µL in each well of a 96-well plate
• Multiplex with other compatible dyes, such as red florescent protein, TMRM, NucBlue™ Hoechst, and CellROX® Deep Red

The fluorescence of the novel pHrodo® Green dye dramatically increases as pH decreases from neutral to acidic, making it an ideal tool to study phagocytosis and its regulation by drugs and/or environmental factors. The lack of fluorescence outside the cell eliminates the need for wash steps and quencher dyes.

Use the ready-made pHrodo® Green Zymosan BioParticles® Conjugate in imaging, high content screening, high throughput screening, and flow applications. pHrodo® Green dye is also available as a conjugate of E. coli BioParticles®, S. aureus BioParticles®, or dextran 10,000. To create other conjugates, such as antibody conjugates, use pHrodo® Green STP ester or pHrodo® Green maleimide.

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

Amplex™ Red Glutamic Acid/Glutamate Oxidase Assay Kit (Invitrogen™)

The Amplex® Red Glutamic Acid/Glutamate Oxidase Assay Kit provides a sensitive and simple method for detecting glutamic acid/glutamate oxidase activity using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect concentrations as low as 10 nM L-glutamic acid or 40 µU/mL of purified L-glutamate oxidase
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

The Amplex® Red Glutamic Acid/Glutamate Oxidase Assay Kit provides an ultrasensitive method for detecting glutamic acid or for continuously monitoring glutamate oxidase activity using a fluorescence microplate reader or fluorometer. In the assay, L-glutamic acid is oxidized by glutamate oxidase to produce α-ketoglutarate, NH3, and hydrogen peroxide. L-alanine and L-glutamate–pyruvate transaminase are included in the reaction to regenerate L-glutamic acid by transamination of α-ketoglutarate, resulting in multiple cycles of the initial reaction and a significant amplification of the hydrogen peroxide produced. The hydrogen peroxide reacts with 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent) in a 1:1 stoichiometric ratio in a reaction catalyzed by horseradish peroxidase (HRP) to generate the highly fluorescent product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

CellTrace™ Violet Cell Proliferation Kit, for flow cytometry (Invitrogen™)

CellTrace™ Violet Cell Proliferation Kit is used for in vitro and in vivo labeling of cells to trace multiple generations using dye dilution by flow cytometry.

• Superior performance—bright, single-peak staining enables visualization of multiple generations
• Long-term signal stability—well-retained in cells for several days post stain
• Versatile—multiple colors available to easily combine with antibodies or markers of cell function, such as GFP
• Simple, robust staining protocol

View a selection guide for all CellTrace™ Cell Proliferation Kits for flow cytometry.

Superior fluorescent staining
Successful proliferation analysis by dye dilution (see figure below) requires an extremely bright dye to distinguish fluorescently labeled cells from auto-fluorescence after several cell divisions. The intense fluorescent staining provided by CellTrace™ Violet dye enables the visualization of ten or more generations of proliferating cells before the signal is overwhelmed by intrinsic cellular auto-fluorescence. Consistent, homogeneous staining results in very little fluorescence variation between cells in a population, so distinct generations can be seen without any requirement for complex modeling software.

Long-term signal retention
Unlike stains that label the lipid membrane of cells, CellTrace™ Violet stain easily crosses the plasma membrane and covalently binds inside cells where the stable, well-retained fluorescent dye provides a consistent signal, even after several days in a cell culture environment. CellTrace™ Violet dye binds covalently to all free amines on the surface and inside of cells and shows little cytotoxicity, with minimal observed effect on the proliferative ability or biology of cells.

Easy multiplexing with other fluorophores
The violet excitation and narrow emission of CellTrace™ Violet dye make it ideal for multiplexing due to the limited spectral overlap with other common dyes (Alexa Fluor™ 488, FITC, and RPE) and fluorescent proteins (Green Fluorescent Protein (GFP) and mCherry) (see Fluorescence Spectra for CellTrace™ Violet stain below).

Simple, robust staining protocol
The CellTrace™ Violet Cell Proliferation Kit contains convenient single-use vials of dry dye to permit small-scale experiments without preparing excess quantities of dye. A stock solution is prepared by dissolving the contents of a vial in anhydrous DMSO prior to use. To stain 1 mL of cells in protein-free medium, 1 µL of this stock solution is typically used. Cells should be stained for 20 minutes at room temperature with gentle agitation. A brief wash with complete medium will then quench any dye remaining in solution.

eBioscience™ Annexin V-FITC 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
FITC

Laser
Blue Laser

Emit
520 nm

Excite
488 nm

Purity
> 98% pure

Molecular Mass
35.8 kDa

Reported Application
Flow Cytometric Analysis

eBioscience™ BrdU Kit for IHC/ICC Immunofluorescence eFluor™ 660 (Invitrogen™)

This BrdU Kit for immunohistochemistry (IHC)/immunocytochemistry (ICC) with immunofluorescence detection contains the necessary reagents and buffers for identifying and examining proliferating cells by immunohistochemical or immunocytochemical analysis. Cells are labeled in vitro or in vivo with 5-bromo-2’-deoxyuridine (BrdU), a synthetic analog of thymidine, which is incorporated into DNA in place of thymidine during the S-phase of the cell cycle. Following fixation and antigen retrieval steps, cells or tissue sections are stained for BrdU incorporation and visualized using a streptavidin-conjugated fluorophore. This kit has been optimized for IHC with both frozen and formalin-fixed paraffin embedded BrdU-labeled mouse intestine and ICC of BrdU-pulsed HeLa cells grown on culture slides.

Conjugate
eFluor 660

Laser
Red Laser

Emit
668 nm

Excite
633 - 647 nm

Reported Application
Immunohistochemical Staining of Formalin-Fixed Paraffin Embedded Tissue Sections, Immunohistochemical Staining of Frozen Tissue Sections, Immunocytochemistry, Microscopy

XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) (Invitrogen™)

XTT is used to assess cell viability as a function of redox potential. Actively respiring cells convert the water-soluble XTT to a water-soluble, orange colored formazan product. Unlike MTT, XTT does not require solubilization prior to quantitation, thereby reducing the assay time in many viability assay protocols. Moreover, the sensitivity of the XTT reduction assay is reported to be similar to or better than that of the MTT reduction assay.