Annexin V-FITC/7-AAD

Description

The kit detects early apoptotic cells using FITC-labeled Annexin V and can be analyzed by flow cytometry or fluorescence microscopy. In viable cells, phosphatidylserine (PS) is on the inner membrane. During early apoptosis, PS moves to the outer membrane. Annexin V is a 35–36 kDa Ca²⁺-dependent phospholipid-binding protein that binds PS with high affinity.

The kit also includes 7-aminoactinomycin D (7-AAD) to identify late apoptotic or necrotic cells. 7-AAD is a DNA dye that cannot penetrate live or early apoptotic cells but stains late apoptotic or necrotic cells. When used together, live cells are Annexin V⁻/7-AAD⁻, early apoptotic cells are Annexin V⁺/7-AAD⁻, and late apoptotic or necrotic cells exhibit double-positive staining (Annexin V⁺/7-AAD⁺).