DAPI is a commonly used nuclear counterstain for fixed cells that emits blue fluorescence when bound to DNA. With NucBlue Fixed Cell ReadyProbes Reagent, we have formulated a high-purity form of this classic stain in a room temperature-stable solution that is provided in a convenient-to-use dropper bottle. Just tip and drip two drops per ml to stain your cells.

Also available: DAPI (4',6-diamidino-2-phenylindole, dihydrochloride) at 12.5X concentration (5 μM) in water.

• No need to dilute, weigh, or pipette
• Convenient dropper bottle—just use two drops per mL
• Stable at room temperature—keep handy at your scope or cell culture area• DAPI is excited with UV light and detected through a blue/cyan filter

See other ReadyProbes reagents for cell staining
See other nuclear stains for imaging

Cell imaging applications
DAPI is a classic fluorescent dye used extensively for nuclear staining of fixed cells. In fluorescence microscopy, DAPI is excited with UV light and detected through a blue/cyan filter (Figure 1)..

Suggestions for use
In most cases 2 drops/ml of NucBlue Fixed Cell Stain and an incubation of 15 to 30 minutes will produce 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.
• NucBlue Fixed Cell Stain is excited by UV light at 360 nm when bound to DNA, with an emission maximum at 460 nm. It is detected through a blue/cyan filter, such as a DAPI filter, blue GFP filters, or the Semrock BrightLine Alexa Fluor 350 Dye filter set.
• As a preferred blue nuclear stain in fixed cell imaging experiments, NucBlue Fixed Cell Stain is ideal for use with antibody-based applications.

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