SYTOX Deep Red Nucleic Acid Stain is a high-affinity nucleic acid stain that easily penetrates cells with compromised plasma membranes and yet does not cross the membranes of live cells. With minimal cytoplasmic staining, SYTOX Deep Red stain is particularly useful in immunocytochemistry (ICC), immunohistochemistry (IHC), and immunofluorescence (IF) experiments for staining of nuclei of fixed cells. After a brief incubation with SYTOX Deep Red stain, the nucleic acids of dead or fixed cells fluoresce a bright, deep red/far red and can be detected with a CY5/Deep Red standard filter set or laser configuration.

Features of SYTOX Deep Red Nucleic Acid Stain include:
• Impermeant to live cells; permeant to dead or fixed cells
• Excitation/emission peak: 660/682 nm
• Use with Cy5 traditional filter set or 647 laser line
• Works with mammalian cells in mono layer or 3D cell culture, animal tissue, and bacteria
• Detectable with fluorescence micro¬scopes, fluorimeters, fluorescence microplate readers, and flow cytometers

SYTOX Deep Red Nucleic Acid Stain is multiplexable with blue, green, orange, red, and near IR fluorophores, when compatible fluorescent filter/laser configurations are used. SYTOX Deep Red stain shows increased fluorescence with increasing concentrations of dsDNA, but does not show much affinity for RNA or ssDNA. It has a bright initial signal and excellent photo stability in a typical imaging experiment. These properties make SYTOX Deep Red stain a simple and quantitative single-step dead/fixed cell nucleus-labeling dye for use with fluorescence micro¬scopes, fluorimeters, fluorescence microplate readers, and flow cytometers.

SYTOX Deep Red Nucleic Acid Stain had been used successfully in mono-layer cells, thin-sliced tissue, thick-sliced tissue, 3D cell cultures/spheroids, and bacteria. It is supplied at a 1 mM concentration in DMSO (∼2000X concentration). A concentration of 0.5 μM (1X) is recommended for most applications and cell types. In fluorescent imaging of various mammalian cells, a concentration range of 2.5 μM to 0.25 μM has been used. For viability testing by flow cytometry, a concentration of 1 μM to 10 nM has been used for Jurkat cells and a range of 4 μM to 0.5 μM has been used with E. coli.