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

Catalog No.	Quantity
C34557	180 Assays
50-112-1516	20 Assays

Catalog No. C34557 Supplier Invitrogen™ Supplier No. C34557

Description

CellTrace™ Violet Cell Proliferation Kit, for flow cytometry

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, 1μL 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.

Specifications

• Content And Storage: Contains 9 vials of CellTrace™ Violet (lyophilized powder) and 1 vial of DMSO (500 μL). Store in freezer (-5 to -30°C) and protect from light.
• Detection Method: Fluorescence
• For Use With (Application): Proliferation Assay
• For Use With (Equipment): Flow Cytometer
• Product Type: Cell Proliferation Kit
• Dye Type: Other Labels or Dyes
• Emission: 405/450
• Form: Lyophilized
• Format: Tube(s)
• Product Line: CellTrace
• Quantity: 180 Assays
• Shipping Condition: Room Temperature
• Solubility: DMSO (Dimethylsulfoxide)

Frequently Asked Questions (FAQs)

I want a dye that can track cells similar to CFSE, but excited with 405 nm violet laser. What is available?

CellTrace Violet and CellTracker Violet BMQC work in the same way as CFSE, but are efficiently excited with the violet laser. They are comparable to CFSE in terms of cell retention, and has been used for tracking cells with microscopy as well as flow cytometry.

I want to do a cell migration study for around 4 hours and need to fluorescently label the cells with a dye. What do you recommend?

Calcein, AM and FDA (fluorescein diaceate) are examples of some dyes used for this application. Since these dyes are not incorporated or covalently attached to any cellular components, they may have a short retention time as some cell types may actively efflux the dye out of the cells. The CellTracker and CellTrace dyes include either a mild thiol-reactive chloromethyl group or amine-reactive succinnimidyl ester group to allow for covalent binding to cellular components, providing for better retention. As with any reagent, one should empirically determine retention times for the cell type used.

I labeled my cells with Calcein, AM, but when I imaged the next day, there was no fluorescence from Calcein. Why?

Calcein, AM is a good choice for cell tracking and as a general cytoplasmic stain. However, it doesn't bind to anything and may be actively pumped out of the cells within a couple hours, which is likely what happened. The retention of Calcein within live cells is dependent upon the inherent properties of the cell type and culture conditions.

For long-term imaging, you may wish to consider a reactive cytoplasmic stains such as CFDA, SE or the CellTracker and CellTrace dyes.

How should I prepare the stock solution for CellTrace Violet Cell Proliferation Kit, for flow cytometry (Cat. No. C34557, C34571)?

To prepare a stock solution of CellTrace Violet Cell Proliferation Kit, for flow cytometry (Cat. No. C34557, C34571), dissolve the contents of one vial in 20 µL of anhydrous DMSO, just prior to use, to give a stock concentration of 5 mM. The recommended working concentration is 5 µM.

I would like to label two cell populations with two different CellTrace reagents and then co-culture these cells. Will the CellTrace reagent leave the cells to stain other cells?

We have not tested the use of the CellTrace reagents for co-culture applications. In theory, this may work, but you would have to test this on your cells of interest.

With the CellTrace cell proliferation kits, for flow cytomtery, I am getting only one broad peak on my histogram instead of multiple peaks. What is causing this?

A single broad peak is usually caused by using too high a concentration of dye and/or too long an incubation time.

What cellular components do the CellTrace Proliferation dyes label?

The dyes provided in the CellTrace Proliferation kits are amine-reactive dyes that are considered general cytoplasmic stains. They may bind to various membrane proteins, organelles as well as components in the cytoplasm. They are not known to localize in any specific organelles.

I am storing the DMSO stock solutions of the CellTrace cell proliferation reagents and am not obtaining a good signal with my cells compared to freshly dissolved dye stock. Why does the product not work after storage?

We provide the CellTrace reagents in small aliquots and strongly recommend discarding any unused DMSO/dye stocks. The CellTrace reagents have acetyl groups to cap the charges on the dyes to make them cell permeant, and succinimidyl ester amine-reactive moiety to allow for covalent attachment to cellular components for long-term retention. Both acetyl groups and succinimidyl esters will readily hydrolyze if any water is present during storage. DMSO is hygroscopic and thus readily absorbs water from the atmosphere. If you must store your dye stocks, you will need to use a good quality, anhydrous DMSO stock that has not been opened often and store the vial within an air-tight container containing some desiccant to keep the DMSO/dye stock solution anhydrous during storage.

I am using the CellTrace Cell Proliferation reagents and am not obtaining good separation of my cell generation peaks. How can I improve the peak separation?

Here are some tips to obtain uniform staining and a bright, unstimulated parent generation peak:

Dissolve the CellTrace dye stock immediately before use in the DMSO provided in the kit or in good quality, anhydrous DMSO to obtain the best reactivity and cell permeability.
Stain in PBS or other amine-free, protein-free physiological buffer. Do not stain in medium.
Start with a single-cell suspension and gently agitate the cells during staining.
Quickly remove the unbound dye by incubating the cells in ice-cold media for 5 minutes and then wash twice more with pre-warmed media.
Include a dead-cell stain in the assay and gate only on live cells.
Analyze as many cells as possible from each sample.
Use a low flow rate for analysis on hydrodynamic focusing cytometers.
A good staining concentration for the CellTrace dyes is generally within 1-10 µM, but the optimal concentration for a particular cell type will vary. Observe your cells in a stain dilution series to determine the optimal concentration for your cells.
Some cell types may take up dye with a broad staining intensity distribution. If this is the case for your cells, then you will need to do an initial sort of the stained, unstimulated parent cells to select for a narrow peak distribution.

Can I store the stock solutions of the CellTrace reagents and how do you recommend storing them?

We provide the CellTrace reagents in small aliquots and strongly recommend discarding any unused DMSO dye stocks. Some of the CellTrace reagents have diacetate groups to cap the charges on the dyes to make them cell permeant, and some have succinimidyl ester amine-reactive groups for long-term cellular retention. Both diacetates and succinimidyl esters will readily hydrolyze if any water is present during storage. DMSO is very hygroscopic and thus readily absorbs water from the atmosphere. We do not recommend storing stock solutions of CellTrace reagents because storage of the product in solution will inevitably lead to partial or complete loss of reactivity.

How do the CellTrace Cell Proliferation reagents work?

CellTrace Cell Proliferation reagents are all cell-permeant dyes that are cleaved by intracellular esterases to yield highly fluorescent compounds that also covalently bind to cellular amines, attaching the dye to various cellular components and providing a very stable signal. These reagents show little cytotoxicity with minimal observed effects on the proliferative ability of many cells.

I want to track my cells with a nucleic acid stain, like DAPI or Hoechst dye. Do you recommend this?

This is not recommended. When these stains bind to DNA and RNA, they may affect the normal function of the nucleic acids, disrupting transcription, as well as replication. Other reagents, such as CellTracker dyes or Qtracker reagents are more optimized for tracking without disrupting normal activity. If a nuclear label is still desired, though, and the cells are mammalian and non-hematopoietic, CellLight nuclear reagents can transiently transfect cells to express GFP or RFP on a nuclear-expressing protein for up to several days without affecting function.

I want to track my cells over time, and you have a lot of options to choose from. How do I pick the right one?

Please see this Web link (http://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/cell-tracking.html) to help you choose the right option for your application. Start by planning how long you want to track your cells, then consider the mechanism of binding. Calcein dyes are very uniform in label and are good for short-term cell migration, but may be rapidly effluxed from some cell types. Lipophilic cyanine dyes, such as DiI, DiO, and similar dyes label cell membranes, don’t disrupt function, and can last longer, but have the potential to cross to other cells if membranes fuse. They are also lost upon permeabilization. CellTracker dyes are better for longer-term labeling, as they possess a mildly reactive chloromethyl moiety that allows covalent binding to cellular components. CFDA SE also covalently binds to cellular components. With all the reagents, their retention within cells is dependent upon the rate of cell division and the inherent properties of the cell (active efflux, membrane and protein turnover rates, etc.) and reagents that allow for covalent attachment exhibit longer retention than those that do not.

The longest-lasting and brightest options are the Qtracker reagents, which are taken up through endocytosis. These are so bright individual quantum dots can be detected, and are also robust enough to survive not only fixation and permeabilization, but even the heat and solvents used in paraffin processing.

I am trying to assay cell proliferation with a CellTrace stain, and I am not seeing separate peaks for each cell division. How can I optimize this assay?

The key to good generational profiles with CellTrace reagents is starting with cells that are evenly labeled so that they have a tight coefficient of variance (CV) when run at time zero after labeling. If the peak is too broad, the generations will overlap each other and the series of peaks will become a hump. Even labeling can be achieved by starting with a uniform cell population (not a mixture of lymphocytes and granulocytes for example) as staining will be proportional to cell size. Cells are labeled rapidly, so you want to pre-dilute the dye and mix it into your cells rapidly. Be sure that the cells are not sitting in a clump in the bottom of your tube. The easiest way to do this is to make a 2x dye solution (1x = 1-10 µM) and resuspend your cells in a half volume of medium (no serum or BSA). Add the dye to the cells and invert a few times to mix. Gently agitate the cells during staining. Once the dye incubation is over (20 min, 37 degrees C), add serum or BSA (at least 1%) to scavenge any remaining unreacted dye. Spin down cells, wash 1x, and resuspend in complete medium. After a 10-20 min incubation to undergo de-esterification, cells are ready to be set up for whatever treatment you are planning. Be sure to keep a time zero control as you need to know where the first generation ran.

What kinds of cell health and viability assays can be performed by flow cytometry?

The following cell health and viability assays can be performed by flow cytometry :

-Apoptosis Assays:
Membrane Asymmetry: Annexin V is a member of a family of structurally related proteins that bind phospholipids in the presence of Ca2+. Annexin V binds several phospholipids, but shows highest affinity for phosphatidylserine.
Phosphatidylserine is normally found in the inner leaflet of the cell membrane; however, in the early stages of apoptosis, phosphatidylserine is observed to translocate to the outer leaflet. This translocation makes phosphatidylserine available for annexin V binding in the presence of Ca2+ containing incubation buffer. Cells undergoing apoptosis will stain with annexin V, while normal cells will not. annexin V is available conjugated with a wide range of fluorophores.

Mitochondrial Health: A distinctive feature of the early stages of apoptosis is the disruption of the mitochondria, including changes in membrane and redox potential. We exclusively offer a number of fluorescent probes for analyzing mitochondrial activity in live cells by flow cytometry, with minimal disruption of cellular function.

The MitoProbe family of mitochondrial stains (MitoProbe DiOC2(3) Assay Kit, Cat. No. M34150, MitoProbe JC-1 Assay Kit, Cat. No. M34152, and MitoProbe DiIC1(5) Assay Kit, Cat. No. M34151) provides quick, easy, and reliable flow cytometric detection of the loss of mitochondrial membrane potential that occurs during apoptosis.

Caspase Activity: The CellEvent Caspase-3/7 Green Flow Cytometry Assay Kit (Cat. No. C10427) enables 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 which targets the recognition sequence for activated caspase-3 and caspase-7, as well as SYTOX AADvanced Dead Cell Stain.

DNA Fragmentation: The later stages of apoptosis are characterized by changes in nuclear morphology, including DNA fragmentation, chromatin condensation, degradation of nuclear envelope, nuclear blebbing, and DNA strand breaks. DNA fragmentation that occurs during apoptosis produces DNA strand breaks, and can be analyzed using TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays. The APO-BrdU TUNEL assay (Cat. No. A23210) is a two-color assay for labeling DNA breaks and total cellular DNA to detect apoptotic cells by imaging or flow cytometry.

Nuclear Chromatin Condensation: The later stages of apoptosis are characterized by changes in nuclear morphology, including DNA fragmentation, chromatin condensation, degradation of nuclear envelope, nuclear blebbing, and DNA strand breaks. Cells undergoing apoptosis display an increase in nuclear chromatin condensation. As the chromatin condenses, cell-permeable nucleic acid stains becomes hyperfluorescent, thus enabling the identification of apoptotic cells when combined with a traditional dead-cell stain. The Vybrant Apoptosis Assay Kit #5, Hoechst 33342/Propidium Iodide (Cat. No. V13244) provides a rapid and convenient assay for apoptosis based on fluorescence detection of the compacted state of the chromatin in apoptotic cells. The Chromatin Condensation & Membrane Permeability Dead Cell Apoptosis Kit with Hoechst 33342, YO-PRO-1, and PI dyes, for flow cytometry (Cat. No. V23201) detects apoptotic cells with changes in nuclear chromatin condensation and plasma membrane permeability.

-Cell Cycle Analysis:
Live cell assays: The Vybrant DyeCycle family of dyes offers robust fluorescent dyes for live-cell cycle analysis with limited cytotoxicity using 405 nm (Cat. No. V35003), 488 nm (Cat. No. V35004), 532 nm (Cat. No. V35005), or 633 nm (Cat. Nos. V10309 and V10273) excitation. The dyes have low cytotoxicity, allowing stained cells to be sorted and otherwise cultured or assessed with functional assays after staining.

Fixed cell assays: Analyzing cell cycle using FxCycle Violet Stain (Cat. No. F10347), SYTOX AADvanced Dead Cell Stain Kit (Cat. No. S10349) or FxCycle Far Red Stain (Cat. No. F10348) allows for multiple color options for simplified fixed cell cycle analysis.

-Cell Proliferation:
Dye dilution assays for cell proliferation: Dye dilution assays for cell proliferation rely on cell membrane–permeant fluorescent molecules. Upon entry into the cell, the dye will covalently bind to amine groups on proteins, resulting in long-term dye retention within the cell. Through subsequent cell divisions, each daughter cell receives approximately half the fluorescence of the parent. Analysis of the fluorescence intensities of cell populations by flow cytometry enables determination of the number of generations through which a cell or population has progressed since the label was applied. CellTrace fluorescent stains can be used without affecting morphology or physiology to trace generations in vivo or in vitro. There is no known effect on proliferative ability or biology of cells and they are well retained in cells for several days post-stain. Available kits for flow cytometry include CellTrace CFSE Cell Proliferation Kit (Cat. No. C34554), CellTrace Violet Cell Proliferation Kit (Cat. No. C34557), and CellTrace Far Red Cell Proliferation Kit (Cat. No. C34564).

DNA Synthesis Assays: Measuring the synthesis of new DNA is a precise way to assay cell proliferation in individual cells or in cell populations. DNA synthesis–based cell proliferation assays measure the rate of new DNA synthesis based on incorporation of modified nucleosides. The Click-iT Plus EdU cell proliferation assay utilizes the power of click chemistry and the modified nucleoside EdU to provide a superior alternative to BrdU staining for detecting and quantitating newly synthesized DNA. The Click-iT Plus EdU cell proliferation assay is available with Pacific Blue (Cat. No. C10636), Alexa Fluor 488 (Cat. Nos. C10632 and C10633), and Alexa Fluor 647 (Cat. Nos. C10634 and C10635).

-Viability Assays:
Dead cells often give false positive results, as they tend to bind non-specifically to many reagents. Therefore, removing dead cells from your flow cytometry data is a critical step to help ensure accurate results and analysis.

Non-fixable Membrane Permeability Stains: SYTOX Dead Cell Stains (Cat. Nos. S34857, S34860, S34861, S34859, and S34862) do not cross intact cell membranes, and they exhibit increased fluorescence upon dsDNA binding, making them some of our most brilliant dead cell stains. Cell-impermeant classic DNA-binding dyes include propidium iodide (Cat. No. P21493) and 7-AAD (Cat. No. A1310). Both of these dyes have been used extensively for viability assays in flow cytometry. CellTrace Calcein AM dyes can be passively loaded into adherent and nonadherent cells. These cell-permeant esterase substrates serve as viability probes that measure both enzymatic activity, which is required to activate their fluorescence, and cell membrane integrity, which is required for intracellular retention of their fluorescent products. Available with blue (Cat. No. C34853), violet (Cat. No. C34858), and green (Cat. No. C34852) fluorescence, these dyes are ideal for short-term staining of live cells and can be used in multiplexed flow cytometry experiments.

Fixable Viability Stains: The LIVE/DEAD Fixable Dead Cell Stains are fixable viability dyes that help to ensure accurate assessment of cell viability in samples after fixation and/or permeabilization. LIVE/DEAD Fixable Dead Cell Stain Kits are based on the reaction of a fluorescent reactive dye with cellular proteins (amines). These dyes cannot penetrate live-cell membranes, so only cell-surface proteins are available to react with the dye, resulting in dim staining. The reactive dye can permeate the damaged membranes of dead cells and stain both the interior and exterior amines, resulting in more intense staining. LIVE/DEAD Fixable Dead Cell Stain Kits are available in eight single-channel colors available for UV, 405, 488, 532, 561, or 633 nm lasers in three packaging sizes to match your experiment.

What are the advantages of flow cytometry?

-Measures data from single cells.
-Data are obtained for a large number of cells, generating a rich statistical analysis of cell populations.
-Because single cells are measured, it will reveal heterogeneity within a population.
-With the ability to multiplex, small sub-populations can be identified.
-Thousands of cells can be analyzed rapidly.
-It is ideally suited for blood samples and other cells in suspension.
-Data can be re-analyzed multiple times after acquisition.
-Flow cytometry files (FCS) can be archived.

What kinds of applications can I run on a flow cytometer?

There are several applications, some of which include immunophenotyping, cell cycle analysis, apoptosis assays such as annexin V staining, CellEvent Caspase-3/7 assay, and TUNEL assay, cell viability, proliferation assays such as CellTrace assay and Click-iT EdU assay, measurements of mitochondrial potential with MitoProbe assays, and cell counting using counting beads.

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