In normal cells, phosphatidylserine (PS) is only distributed on the inner side of the lipid bilayer of the cell membrane, while in the early stage of cell apoptosis, phosphatidylserine (PS) in the cell membrane flips from the inner side of the lipid membrane to the outer side. Annexin V is a Ca2+-dependent phospholipid binding protein with a molecular weight of 35~36kD. It has a high affinity with phosphatidylserine, so it can bind to the cell membrane of early apoptotic cells through the phosphatidylserine exposed on the outside of the cell. Therefore, Annexin V is used as one of the sensitive indicators for detecting early cell apoptosis. Annexin V is labeled with fluorescein (EGFP, FITC), and the labeled Annexin V is used as a fluorescent probe to detect the occurrence of cell apoptosis using a fluorescence microscope or flow cytometer.
Experimental steps:
1. Collect cells
2. Add 5μL Annexin V-FITC and mix gently
3. Incubate at room temperature away from light
4. Centrifuge, add Annexin V-FITC to resuspend cells
5. Add staining solution and store at room temperature away from light
6. Flow cytometer test
Result example:
