7-AAD (7-Aminoactinomycin D), 200tests

A fluorescent cell viability dye from STEMCELL Technologies, 7-AAD (7-Aminoactinomycin D) is excluded from live cells with intact membranes but penetrates dead or damaged cells, binding to double-stranded DNA with high affinity by intercalating between GC base pairs. It is often used as an alternative to propidium iodide (PI) to differentiate and exclude non-viable cells in flow cytometric analyses, and can be excited using 488 nm (blue), 532 nm (green), and 561 nm (yellow-green) laser lines. Compared to PI, the dye offers minimal overlap in its emission spectra with mostly blue and green, and many red fluorophores, including the commonly used phycoerythrin (PE) and fluorescein isothiocyanate (FITC).

It is also used in DNA fluorescence imaging applications to discriminate early and late stages of apoptosis, to study cell-mediated cytotoxicity, and for chromosome banding analysis. The dye has been found to exhibit antibacterial properties and growth-inhibitory activity against certain types of leukemia and sarcoma. For flow cytometry, use 5 µL (0.25 µg) of dye solution per 1 x 10^6 cells in 100 µL. Incubate cells with the dye for 5 - 10 minutes in the dark, then analyze immediately, and titrate for optimal performance in each application.

Supplied in phosphate-buffered saline, pH 7.2, containing 0.09% sodium azide. Store at 2 - 8°C; do not freeze. Protect product from prolonged exposure to light; it is stable until the expiry date (EXP) on the label. Reported applications include chromosome banding, functional assay (FA), flow cytometry (FC), fluorescence microscopy, immunocytochemistry (ICC), and immunofluorescence (IF), and the dye has been verified for viability assessments of cells isolated with EasySep™ and RosetteSep™ kits. The chemical formula is C₆₂H₈₇N₁₃O₁₆ with a molecular weight of 1270.4 g/mol. Excitation wavelengths are 546 nm (DNA complex) and 503 nm (free form); emission wavelengths are 647 nm (DNA complex) and 675 nm (free form).