DAPI
DAPI (Ex-Max 354 nm/Em-Max 456 nm)
DAPI (4',6-diamidino-2-phenylindole (DAPI) is a blue-emitting fluorogenic DNA-binding dye that can be excited by the 355 nm blue laser and captured with a 450/50 nm bandpass filter. DAPI has an excitation peak at 350 nm and an emission peak at 465 nm. DAPI is a commonly used DNA stain that binds to AT regions and has many favorable properties. DAPI's fluorescence increases upon binding to DNA, which is beneficial for signal to background ratios. Additionally, DAPI passes through both dead and live cell membranes, with varied success. It passes through dead cell membranes much more effectively making it better for fixed, dead cell staining. It can be used with live cells, but this requires a higher concentration of the dye or can be used to detect membrane depolarization in apoptosis. DAPI is a generic dye sold by many suppliers.
Excitation & emission spectra
Key facts
- Excitation maximum
- 354 nm
- Emission maximum
- 456 nm
- Optimal laser line
- 355/405
- Optimal filter
- 450/50
- Extinction coefficient
- 27000
- Quantum yield
- 0.92 (bound)
- Molecular weight
- 277
- Commercial antibodies
- 8 from 8 suppliers
DAPI has an excitation maximum at 354 nm and an emission maximum at 456 nm, a Stokes shift of 102 nm. Its extinction coefficient is 27000 M⁻¹cm⁻¹. It is optimally excited by the 355/405 laser line.
Frequently asked questions
- What is DAPI?
- DAPI (4',6-diamidino-2-phenylindole (DAPI) is a blue-emitting fluorogenic DNA-binding dye that can be excited by the 355 nm blue laser and captured with a 450/50 nm bandpass filter. DAPI has an excitation peak at 350 nm and an emission peak at 465 nm. DAPI is a commonly used DNA stain that binds to AT regions and has many favorable properties. DAPI's fluorescence increases upon binding to DNA, which is beneficial for signal to background ratios. Additionally, DAPI passes through both dead and live cell membranes, with varied success. It passes through dead cell membranes much more effectively making it better for fixed, dead cell staining. It can be used with live cells, but this requires a higher concentration of the dye or can be used to detect membrane depolarization in apoptosis. DAPI is a generic dye sold by many suppliers.
- What laser excites DAPI?
- DAPI is optimally excited by the 355/405 laser line. Its excitation maximum is 354 nm.
- What filter should I use to detect DAPI?
- A 450/50 filter captures the peak of the DAPI emission near 456 nm with minimal spillover.
- How many antibodies are available conjugated to DAPI?
- FluoroFinder tracks 8 commercially available DAPI conjugates, searchable by target, clone, host and application.