Annexin V-FITC/PI Apoptosis Detection Kit

Product Description

Annexin V-FITC/PI Apoptosis Detection Kit is designed for the detection of early-stage apoptosis in cells. Annexin V, a member of the cellular protein family known as annexins, binds selectively and in a calcium-dependent manner to phosphatidylserine (PS).

Under normal circumstances, PS is located on the inner side of the cell membrane, adjacent to the cytoplasm. During the early stages of apoptosis, various cell types expose PS on the outer leaflet of the cell membrane. By utilizing Annexin V conjugated with FITC (Fluorescein Isothiocyanate), known as Annexin V-FITC, this important apoptotic hallmark of PS externalization can be detected via flow cytometry or fluorescent microscopy.

Propidium Iodide (PI) is a nuclear staining dye that stains DNA and emits red fluorescence upon intercalation into DNA. PI cannot penetrate intact cell membranes but can enter cells that have lost membrane integrity, such as late-stage apoptotic or necrotic cells. Therefore, when Annexin V is used in conjunction with PI, live cells exclude PI (Annexin V-/PI-), and early apoptotic cells are only stained with Annexin V (Annexin V+/PI-). Late-stage apoptotic and necrotic cells are double-stained with both FITC and PI, presenting as double-positive (Annexin V+/PI+).

The maximum absorption wavelength for FITC is 490 nm, with an emission wavelength of 525 nm. For the PI-DNA complex, the maximum absorption and emission wavelengths are 535 nm and 615 nm, respectively.

Performance

Figure 1. After incubating C6 cells (rat glioma cells) with apoptosis activator 2 (MB4124) for 1.5 hours, our Annexin V-FITC/PI apoptosis detection kit was used to detect the staining effect.

Cells stained only by green fluorescence are pre-apoptotic cells, while cells stained double-stained by green and red are late apoptotic or necrotic cells.

Figure 2. Flow cytometry detection diagram after staining using our company’s Annexin V-FITC/PI apoptosis detection kit.

After A549 cells (human non-small cell lung cancer cells) were treated with 100 μM apoptosis activator 2 (MB4124) for 5 hours, they were not stained (A), stained only with the PI in this kit (B), only stained with Annexin V-FITC in the kit (C), and stained with both Annexin V-FITC and PI in this kit (D). It can be seen that the unstained cells are double-negative cells (A), the expected PI-positive cells appeared only after PI staining, and the expected Annexin V-FITC-positive cells appeared only after Annexin V-FITC staining. Stained with both Annexin V-FITC and PI showed the expected early apoptotic cells that were only positive for Annexin V-FITC and double-positive late apoptotic cells. The occurrence of unexpected cell was well within the allowed error range.

The actual measured data may vary due to different cell types, cell apoptosis conditions, detection instruments, etc. The data in the figure are for reference only.

Shipping and Storage 

• Storage：-Store in the dark at 2–8°C, and the product is valid for one year from the date of manufacture. Annexin V-FITC should not be frozen.
• Shipment：

Usage Statement

Research Use Only (RUO)