Image of NucBlue® Fixed Cell ReadyProbes® Reagent packaging

Nuclear stain for live cells

NucBlue® Live reagent (Hoechst® 33342 dye) stains the nuclei of all cells. NucBlue® Live reagent is frequently used to distinguish condensed nuclei in apoptotic cells.

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:


1. Culture cells in an appropriate medium and vessel for fluorescence microscopy
2. Add two drops of NucBlue® Live ReadyProbes® Reagent per milliliter of medium
3. Incubate for 20 minutes, protected from light.
4. Image the cells.
Spectral information and storage
Excitation/Emission (nm) 360/460
Standard filter set DAPI
EVOS® Light Cube DAPI
Storage conditions Room temperature


Protocol tips

U2OS live-cell staining
U2OS live-cell staining. Live U2OS cells were imaged 15 minutes following staining with NucBlue® Live ReadyProbes® Reagent.