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Annexin V, APC conjugate (APC Annexin V), 250 μL - FAQs

Annexin V, APC conjugate (APC Annexin V), 250 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

When should I use Annexin V instead of an Invitrogen CellEvent Caspase Detection Reagent?

Choose Annexin V to detect phosphatidylserine exposure at the plasma membrane, and choose Invitrogen CellEvent Caspase Detection Reagents to detect activated caspases and nuclear fluorescence. The methods measure different apoptotic events and should not be treated as interchangeable.

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 staining?

Yes, this is possible. We have established protocols for annexin V staining combined with intracellular staining of lymphocytes that can be found here. The most important step is to leave some binding buffer in the suspension when fixation is started. Compared to staining of live cells, the intensity of the annexin V signal may be somewhat reduced.

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.