Protocol for a DAPI Stain

DAPI stands for the chemical 4'-6-Diamidino-2-phenylindole, and is used to stain double-stranded DNA. The compound forms blue fluorescent complexes with nuclei of cells and so is used commonly to highlight the structure of cells. The type and density of staining also can identify dead or dying cells.

Preparing DAPI Solution

• The DAPI solution first must be diluted to a working solution. For example, 10 mg of the Invitrogen DAPI product must be mixed with 2 mL of deionized water, and then diluted further to 300 nano-Molar concentration (directions will be present on the product) with phosphate-buffered saline (PBS).

Preparing the Sample

• Fix the sample as appropriate to the type of sample to be tested onto a slide. Add 300 microliters of the DAPI working solution to the sample and incubate for one to five minutes. Rinse the slide with PBS.

Analyzing

• Use a fluorescence microscope to look at the slide-mounted sample. The DAPI-stained nuclei can be identified by a blue fluorescence.