As a counterstain in fluorescence imaging methods, DAPI is compatible with antibodies and other probes labeled with fluorescein and rhodamine dyes, as well as with Thermo Scientific DyLight* Fluors. DAPI has greater photostability than Hoechst dyes, although Hoechst 33342 can be use for live cell imaging while use of DAPI is confined to fixed cells. DAPI is offered in powdered solid and aqueous solution forms.
Highlights:
- Nuclei detection– binds specifically and quantitatively with DNA to facilitate specific detection of nuclei and DNA content in fluorescence imaging
- Fluorescent– yields blue fluorescent product to enable measurement with fluorescence microscopes and imagers (excitation 341nm, emission 452nm)
- Fixed cells– especially for use with fixed cells rather than live-cell samples
- Compatible counterstain–provides effect counterstaining alongside fluorescein and other fluorescent probes, such as Thermo Scientific DyLight Fluors
Recommended for: Assaying DNA in solution; Diagnosing mycoplasmal infection of cell cultures; Measuring nuclear content and sorting chromosomes in flow cytometry; Assessing apoptosis; Detecting nuclei and organellar DNA in immunofluorescent and in situ hybridization procedures; Replacing ethidium bromide for staining DNA in agarose gel; Counterstaining nuclei in histochemical methods when red-fluorescent antibodies have been used to detect specific targets; Reports also indicate that DAPI will bind to polyphosphates and other polyanions, dextran sulfate and SDS
DAPI (diamidino-2-phenylindole) is a blue fluorescent probe that fluoresces brightly upon selectively binding to the minor groove of double stranded DNA, where its fluorescence is approximately 20-fold greater than in the nonbound state. Its selectivity for DNA and high cell permeability allows efficient staining of nuclei with little background from the cytoplasm. DAPI is a classic nuclear counterstain for immunofluorescence microscopy, as well as an important component of high-content screening methods requiring cell-based quantitation of DNA content.
