image of Molecular Probes® NucRed® Dead 647 ReadyProbes® Reagent

Nuclear stain for fixed cells

NucRed® Dead 647 ReadyProbes® Reagent emits bright far-red fluorescence when bound to DNA and is suitable for staining nuclei in fixed-cell preparations and tissue sections. NucRed® Dead 647 reagent may also be used to measure viability and to measure cytotoxicity in kinetic live-cell assays. 

This protocol can be used for:

  • Nuclear staining to identify nuclear condensation in apoptotic cells using fluorescence microscopy

This protocol should not be used for:

  • Flow cytometry

You will need the following for this protocol:


Labeling fixed cells

First, fix and permeabilize cultured cells with a protocol appropriate for your sample.

1. Wash the cells 1–3 times in PBS as needed.
2. Add two drops of NucRed® Dead 647 Reagent per milliliter of medium.
3. Incubate for 5–15 minutes, protected from light.
4. Remove the stain solution.
5. Wash the cells 2–3 times in PBS.
6. Image the cells.
Spectral information and storage
Excitation/Emission (nm) 642/661
Standard filter set Cy®5
EVOS® Light Cube Cy®5
Storage conditions Room temperature




Protocol tips

tubulin and nuclear staining in HeLa cells
Tubulin and nuclear staining in HeLa cells. HeLa cells were fixed and permeabilized and stained for tubulin (biotinylated mouse anti-a-tubulin mouse monoclonal antibody followed by an Alexa Fluor® 488 goat anti-mouse secondary antibody and counter-stained with NucRed® Dead 647 ReadyProbes® reagent.