About 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.