The Annexin V-YSFluor™ 647/PI Apoptosis Detection Kit uses Annexin V conjugated to YSFluor™ 647 as a probe to detect early-stage apoptosis in cells. The assay can be analyzed by flow cytometry or other fluorescence detection instruments.

Principle of Detection:In healthy viable cells, phosphatidylserine (PS) is localized on the inner leaflet of the plasma membrane. However, during early apoptosis, PS is translocated to the outer surface of the cell membrane and becomes exposed to the extracellular environment. Annexin V is a 35–36 kDa Ca²⁺-dependent phospholipid-binding protein with high affinity for PS. It binds specifically to PS exposed on the outer membrane of early apoptotic cells.

Additionally, this kit includes Propidium Iodide (PI), a nucleic acid dye used to distinguish viable early apoptotic cells from late apoptotic or necrotic cells. PI cannot penetrate intact membranes of live or early apoptotic cells but readily enters cells with compromised membranes—such as late apoptotic or necrotic cells—and stains their nuclei red.

Therefore, when Annexin V and PI are used together:

Viable cells are Annexin V⁻/PI⁻

Early apoptotic cells are Annexin V⁺/PI⁻

Late apoptotic and necrotic cells are Annexin V⁺/PI⁺ (double-positive)

This kit requires analysis by flow cytometry.

Features

Rapid and Convenient Detection – Simple workflow enables fast assessment of apoptosis in cultured cells without complex procedures.

High Accuracy – Dual staining with Annexin V-YSFluor™ 647 and Propidium Iodide (PI) allows precise discrimination between early apoptotic, late apoptotic, necrotic, and live cells.

Sensitive and Reliable – Optimized fluorophore conjugation and buffer formulation ensure strong signal with minimal background, suitable for flow cytometry and fluorescence microscopy.

Versatile – Compatible with a wide range of cell types, including adherent and suspension cells.

Components