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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.

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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.


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


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