4’,6-Diamidino-2-phenylindole hydrochloride (DAPI), 98%, CAS No. : [28718-90-3

DAPI is a fluorescent stain that binds strongly to DNA. It is used extensively in fluorescence microscopy. Since DAPI passes through an intact cell membrane, it can be used to stain live cells and fixed cells. For fluorescence microscopy, DAPI is excited with ultraviolet light. When bound to double-stranded DNA its absorption maximum is at 358 nm and its emission maximum is at 461 nm. DAPI also binds to RNA although it is not as strongly fluorescent as when it binds to DNA and its emission shifts to around 500 nm

DAPI's blue emission is convenient for multiplexing assays since there is very little fluorescence overlaping between DAPI and green-fluorescent molecules such as fluorescein and green fluorescent protein (GFP), or red-fluorescent stains such as Texas Red. DAPI is also used for the detection of mycoplasma or virus DNA in cell cultures.

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