Annexin V, Alexa Fluor™ 594 conjugate, 500 μL - FAQs

View additional product information for Annexin V Conjugates for Apoptosis Detection - FAQs (A23202, A13202, A35108, A13201, A35109, A13204, A13203, A23204, A13199, A35111, A35122, A35110)

8 product FAQs found

I want to study apoptosis using an Annexin V conjugate, but with adherent cells via microscopy instead of flow cytometry. Can this be done?

It has been done, but we don‘t recommend it. Both healthy cells and apoptotic cells possess phosphatidylserine on the cell surface, which can be detected with Annexin V, but apoptotic cells have significantly more of it. You can easily tell the difference between these two populations with flow cytometry, because flow cytometers are more sensitive and have a higher throughput. But with a microscope, you cannot always tell the difference, especially for adherent cells. Instead, for microscopy, we recommend a different technique, such as detecting caspases with CellEvent Caspase Detection Reagents.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

I trypsinized my adherent cells and labeled with annexin V, and now my flow data is showing a high percentage of apoptotic cells even for control, untreated cells. What is the problem?

Trypsinization or mechanical scraping of cells temporarily disrupts the plasma membrane, allowing annexin V to bind phosphatidylserine on the cytoplasmic surface of the cell membrane and thus leading to false positive staining. Allow the cells to recover for about 30 minutes in optimal cell culture conditions and medium after trypsinizing/scraping so that they can recover their membrane integrity before staining. For lightly adherent cell lines, such as HeLa and NIH 3T3, another option is to use non-enzyme treatments like Gibco Cell Dissociation Buffer (Cat. No. 13151014).

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Can I detect annexin V staining in an imaging assay?

Annexin V staining is not typically used in imaging experiments; it is a better reagent for flow cytometry analysis. All cells will stain to some extent, so it can be difficult to distinguish a relatively bright annexin V-stained cell from a dimmer non-apoptotic cell. Caspase activation, detected using our CellEvent Caspase 3/7 or Image-iT LIVE Caspase detection kits, is a better method for detecting apoptosis in an imaging assay.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

When should I stain adherent cells with annexin V for flow cytometric analysis? Before or after I trypsinize them?

Trypsinize first and then allow the cells to recover about 30 minutes in optimal cell culture conditions and medium before staining with annexin V conjugates. Trypsinization or mechanical scraping of cells temporarily disrupts the plasma membrane, allowing for annexin V to bind phosphatidylserine on the cytoplasmic surface of the cell membrane and thus leading to false positive staining. For lightly adherent cell lines such as HeLa and NIH 3T3, you could use a less harsh (non-enzymatic) dissociation product like Gibco Cell Dissociation Buffer (Cat. No. 13151014).

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Can I fix my cells after annexin V labeling?

Annexin V staining is best analyzed on live cells. If you need to fix your cells for analysis, then fix in 3.7% formaldehyde in PBS containing calcium and magnesium to maintain binding during fixation. The signal will not be retained after permeabilization, thus annexin V staining is not compatible with internal antibody labeling.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

I am trying to label adherent cells with annexin V and am finding that everything is getting labeled. How can I fix this?

Treating cells with trypsin or other reagents to detach adherent cells causes damage to the membrane, such that cells will be labeled with annexin V. The best way to avoid this problem is to allow your cells to recover for 30-45 min in the incubator. Swirl the tube/plate/flask every few minutes to prevent re-attachment. After this recovery period, you can label your cells with annexin V and analyze by flow cytometry.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

What are the advantages of flow cytometry?

-Measures data from single cells.
-Data are obtained for a large number of cells, generating a rich statistical analysis of cell populations.
-Because single cells are measured, it will reveal heterogeneity within a population.
-With the ability to multiplex, small sub-populations can be identified.
-Thousands of cells can be analyzed rapidly.
-It is ideally suited for blood samples and other cells in suspension.
-Data can be re-analyzed multiple times after acquisition.
-Flow cytometry files (FCS) can be archived.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

What kinds of applications can I run on a flow cytometer?

There are several applications, some of which include immunophenotyping, cell cycle analysis, apoptosis assays such as annexin V staining, CellEvent Caspase-3/7 assay, and TUNEL assay, cell viability, proliferation assays such as CellTrace assay and Click-iT EdU assay, measurements of mitochondrial potential with MitoProbe assays, and cell counting using counting beads.

Find additional tips, troubleshooting help, and resources within our Flow Cytometry Support Center.