NucRed™ Dead 647 ReadyProbes™ Reagent is a cell impermeant stain that emits bright far-red fluorescence when bound to DNA. Cells that have lost plasma membrane integrity are stained within minutes, making this an extremely useful stain to estimate live/dead cell ratios and to measure cytotoxicity in kinetic live cell assays. NucRed™ Dead 647 reagent is also suitable for staining nuclei in fixed cell preparations and tissue sections. Like other ReadyProbes™ reagents, NucRed™ Dead 647 reagent is formulated as a room temperature-stable solution and comes in a convenient dropper bottle. Just tip and drip two drops per ml to stain your cells.

NucRed™ Dead 647 ReadyProbes™ Reagent provides:
• Exceptionally bright far-red fluorescence upon binding to DNA
• Rapid staining of damaged, dead, or fixed cells without wash steps
• Ready-to-use liquid formulation in convenient dropper bottle—no need to dilute, weigh, or pipette
• Stability at room temperature—keep handy at your scope or cell culture area

Far-red Dead Cell Nuclear Stain for Cellular Imaging
The membrane-impermeable NucRed™ Dead 647 reagent is a high-affinity DNA stain that easily stains cells with compromised cell membranes, yet does not enter living cells. It is therefore ideal for discrimination of live and dead cells. The fluorescence increases several hundred-fold on binding to dsDNA in cells with compromised cell membranes (dying or dead cells), in fixed cells, and tissue slices. The spectral properties, with excitation/emission at 642/661 nm when bound to DNA, is ideal for standard FITC filters.

Packaged for Convenience
NucRed™ Dead 647 ReadyProbes™ Reagent is supplied ready-to-use and can be stored right next to your microscope or workstation. A liquid formulation in an ultra-convenient dropper bottle (Figure 2) allows you to stain your cells whenever and wherever they are ready. Just add two drops per ml for optimally bright and distinct nuclear counter-staining.

Multiple Applications
The properties of NucRed™ Dead 647 ReadyProbes™ Reagent (excitation/emission of 642/661 nm) make it ideal for live/dead cell discrimination. It can also be used for staining of fixed cells or tissue slices and for counting dead cells. The long-wavelength fluorescence of the NucRed™ Dead 647 dyeis well separated from that of commonly used fluorophores, such as Hoechst, GFP, Alexa Fluor® 488, rhodamine (TRITC), Texas Red® and many RFP variants. NucRed™ Dead 647 ReadyProbes™ Reagent is well-suited for tissue staining, as its signal is generally not obscured by tissue autofluorescence.

Suggestions for Use
• NucRed™ Dead 647 ReadyProbes™ Reagent may be added directly to cells in full media or buffer solutions
• It easily stains nuclei of fixed cells and tissue slices
• In most cases 2 drops/ml and an incubation time of 15 to 30 minutes will give bright nuclear staining; however, optimization may be needed for some cell types, conditions, and applications. In such cases, simply add more or fewer drops until the optimal staining intensity is obtained. In most cases, staining intensity increases with time if cells are not washed prior to imaging.
• NucRed™ Dead 647 dye is excited with a maximum at 642 nm when bound to DNA, with an emission maximum at 661 nm. It is detected through far-red filters, such as the Semrock 660/52 nm BrightLine® single-band bandpass filter.

See other Molecular Probes® imaging tools and reagents.