Figure 4. Discrimination of live and dead cells using the Live-or-Dye NucFix™ Red Fixable Viability Stain. A. Live or heat-killed Jurkat cells were stained with Live-or-Dye NucFix™ Red. Heat killed cells (solid peak) showed much higher fluorescence intensity compared to live cells (white peak), allowing the two populations to be clearly distinguished. B. Ethanol-treated HeLa cells were stained with NucFix™ Red together with Hoechst to label all cell nuclei. Killed cells show bright, red nuclear Live-or-Dye™ fluorescence staining, compared to no staining seen in live cells (blue Hoechst-stained nuclei).