Annexin V conjugates provide quick and reliable detection methods for studying the externalization of phosphatidylserine, an indicator of intermediate stages of apoptosis. The difference in fluorescence intensity between apoptotic and nonapoptotic cells stained with our fluorescent annexin V conjugates, as measured by flow cytometry, is typically about 100-fold.

The Annexin V Ready Flow conjugates are provided as ready-to-use, direct-to-sample apoptotic cell stains. Simply add one drop from the dropper bottle directly into 1 x 106 cells in 5 mM Ca2+-containing cell culture medium or annexin binding buffer (Cat. Nos. V13246 or BMS500BB), incubate, and analyze. The traditional annexin staining protocol can be used as an alternative method by replacing the addition of 5 μL annexin conjugate with the addition of 1 drop from the Ready Flow dropper bottle.

The Annexin V Alexa Fluor 488 conjugate is excitable at 495 nm with an emission peak at 519 nm.
The Annexin V Alexa Fluor 647 conjugate is excitable at 650 nm with an emission peak at 665 nm.
The Annexin V APC conjugate is excitable at 650 nm with an emission peak at 660 nm.
The Annexin V Pacific Blue conjugate is excitable at 410 nm with an emission peak at 455 nm.
Annexin V staining to detect apoptotic cells can only be done on live cells and tissue. If samples are to be fixed post-staining, there are specific conditions required to achieve transient retention of signal. These include use of an alcohol-free, aldehyde-based fixation method, use of buffers containing Ca2+ and avoidance of surfactants/detergents. For your convenience, we also offer a concentrated annexin-binding buffer that facilitates the binding of annexin V to phosphatidylserine in apoptosis assays.