Apotracker™ Green (Apo-15)

Calcium-Independent Apoptosis Probe

Non-antibody probes can be particularly useful in apoptosis detection assays. Annexin V has historically been a gold standard for general apoptosis detection when coupled with another probe for necrosis like impermeant nucleic acid stains (Helix NP™ probes) and esterase substrates (Calcein-AM probes). Annexin V, however, depends on Ca2+ in the staining media. It can also exhibit high background staining and be difficult to incorporate in microscopy applications. Detected in the FITC channel, Apotracker™ Green (Apo-15) is a fluorogenic probe that binds to apoptotic cells in a Ca2+ independent manner, while exhibiting a linear relationship with Annexin V staining, suggesting they are both detecting externalized PS residues. Apotracker™ Green is also useful in microscopy applications on live cells and is retained with paraformaldehyde fixation.

Early Stage-> Mid Stage-> Late Stage Apoptosis

Apotracker™ Green signal is preserved post-fixation

Apotracker™ Green signal is preserved post-fixation


Apotracker™ Green (Apo-15) data Day-old murine splenocytes were stained with Apotracker™ Green, washed and then either analyzed unfixed (black) or fixed with FluoroFix™ Buffer (red). Signal could be affected by other harsher fix and permeabilization reagents.

Identify cells in apoptosis by flow cytometry and microscopy

Apotracker™ Green (Apo-15) microscopy image 5-day old HeLa cells were stained with Calcein Red-AM (an indicator of live, healthy cells), Helix NP™ Blue, and Apotracker™ Green (Apo-15).


Flow data with Apotracker™ Green (Apo-15) (Left) Day-old splenocytes, gated on Helix NP™ NIR negative cells to exclude necrotic cells. (Right) Helix NP™ NIR-negative cells (red gate, left plot) stained for Apotracker™ Green and BV421™ Annexin V. Staining was performed with Annexin Binding Buffer according to BioLegend protocol. It has not been determined if Annexin V and Apotracker™ Green compete for binding sites.

Apotracker™ Green labels apoptotic, dead cells without the need for specialized buffers

Apotracker™ Green (Apo-15) flow data image Unstimulated (left) and CD95-stimulated (right) Jurkat cells were stained with Apotracker™ Green (Apo-15) and Helix NP™ NIR. Cells were stained for 10-15 min in FACS buffer followed by two washes prior to analysis.


To learn more, visit our Apoptosis page.

Insert Note Here
Save Close Clear
Lab Timer
Remember me
Forgot your password? Reset Password
Request an Account