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Live-or-Dye NucFix™ Red Staining Kit

A red fluorescent dye to covalently label dead cells, allowing cells with permeable plasma membranes to be detected in flow cytometry and microscopy.

Product Attributes

Apoptosis/viability marker

Dead cell stain

For live or fixed cells

Covalent & fixable stains, For live/intact cells

Assay type/options

Endpoint assay

Detection method/readout

Fluorescence microscopy, Flow cytometry

Fixation options

Fix after staining (formaldehyde), Fix after staining (methanol), Permeabilize after staining




520/593 nm (with DNA)

Storage Conditions

Store at -10 to -35 °C, Protect dye component from light, Desiccate

Note: Due to operating restrictions related to our COVID-19 response, primary antibody conjugates of R-PE, APC, PerCP, HRP, or AP are temporarily unavailable. All other antibody options are still available. We apologize for the inconvenience. Please see our easy-to-use Mix-n-Stain™ Antibody Labeling Kits for labeling antibodies with R-PE, APC, tandem dyes, and enzymes.
Catalog #
50 assays
200 assays
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Product Description

Live-or-Dye NucFix™ Red is a red fluorescent nuclear dye that covalently labels cells with permeable plasma membranes, allowing dead cells to be detected in flow cytometry and microscopy.


  • Nuclear-specific dead cell stain
  • Highly dead-cell specific
  • Covalent labeling with reactive dye
  • Withstands fixation and permeabilization
  • Selective dead-cell staining of mammalian cells, yeast, or gram-negative bacteria

Kit Components

  • Live-or-Dye NucFix™ Red Dye
  • Anhydrous DMSO

    Note: Number of assays is based on 1 mL reaction size (106 cells); actual number of assays may vary depending on staining volume

Spectral Properties

  • Ex/Em: 520/593 nm (with DNA)

About Live-or-Dye™

Biotium’s line of Live-or-Dye™ Fixable Viability Staining Kits are designed for discrimination between live and dead cells during flow cytometry or microscopy. Live/dead stains are useful probes to include when analyzing cell surface protein expression by flow cytometry, because they allow intracellular fluorescence signal from dead cells with permeable plasma membranes to be excluded from analysis. In microscopy, live/dead stains allow unambiguous visual discrimination of dead cells.

NucFix™ Red

Live-or-Dye NucFix™ Red is a reactive, cell membrane impermeant dye that specifically stains the nuclei of dead cells. The dye is able to enter into dead cells that have compromised membrane integrity and covalently label the cell nucleus, allowing for clear differentiation of live and dead cells by either microscopy or flow cytometry. Unlike other commonly used nuclear stains such as Propidium Iodide (PI) or DRAQ7™, NucFix™ labeling is extremely stable, allowing the cells to be fixed and permeabilized without loss of fluorescence or dye transfer between cells. The Live-or-Dye NucFix™ Red staining protocol has been optimized to maximize live/dead discrimination with minimal live cell staining, in order to prevent interference with immunostaining.

Live-or-Dye NucFix™ Red can also be used as a fixable dead cell stain in gram-negative bacteria. In gram-positive strains there may be live cell staining. Live-or-Dye NucFix™ Red is dead cell specific but not nuclear in yeast. See our Cellular Stains Table for more information on how our dyes stain various organisms.

Catalog No.

Viability Dye

Laser line

Emission filter

Abs/Em Max


32002, 32002-TLive-or-Dye™ 350/448355 nmDAPI or Violet355/450 nmFlow Cytometry
32014,32014-TLive-or-Dye™ 375/600355 or 405 nmSpectral Scan373/595 nmSpectral Cytometry
32003, 32003-TLive-or-Dye™ 405/452405 nmPacific Blue®416/452 nmFlow Cytometry
32009, 32009-TLive-or-Dye™ 405/545405 nmAmCyan413/547 nmFlow Cytometry
32004, 32004-TLive-or-Dye™ 488/515488 nmFITC490/516 nmFlow Cytometry,
32012, 32012-TLive-or-Dye™ 510/550488 nmSpectral scan516/549 nmSpectral Cytometry
32005, 32005-TLive-or-Dye™ 568/583488 or 561 nmPE562/584 nmFlow Cytometry,
32006, 32006-TLive-or-Dye™ 594/614488 or 561 nmPE-Texas Red®593/615 nmFlow Cytometry,
32015, 32015-TLive-or-Dye™ 615/740633 nmSpectral scan612/744 nmSpectral Cytometry
32007, 32007-TLive-or-Dye™ 640/662633 or 640 nmAPC642/663 nmFlow Cytometry, Microscopy
32013, 32013-TLive-or-Dye™ 665/685633 or 640 nmSpectral scan667/685 nmSpectral Cytometry
32008, 32008-TLive-or-Dye™ 750/777633 or 640 nmAPC-Cy®7755/779 nmFlow Cytometry
32011, 32011-TLive-or-Dye™ 787/808785 or 808 nmAPC-Cy®7 or IR800783/808 nmFlow Cytometry
32010, 32010-TLive-or-Dye NucFix™ Red488 or 532 nmPE-Texas Red®520/593 nmFlow Cytometry,


1. Cell Transplant (2019).
2.Access Microbiology (2019).


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