How to Detect Early Apoptosis?

During the early stages of cell apoptosis, phosphatidylserine (PS) on the inner side of the cell membrane translocates to the outer side, exposing itself to the extracellular environment. This leads to an increase in cell membrane permeability, allowing specific binding of PS to Annexin-V probes. Currently, Arcegen offers an Annexin-V Cell Apoptosis Detection Kit suitable for early apoptosis detection. Annexin-V is a Ca2+-dependent phospholipid-binding protein with a strong affinity for PS. Additionally, this assay kit provides PI/7-AAD for dual staining. Since normal cells are not stained, early apoptotic cells can be labeled with Annexin-V, while necrotic or late apoptotic cells are stained with PI/7-AAD, allowing clear differentiation of cells at various stages.
Figure 2. Principle of Annexin-V Experiment
Performance Highlights:
1. Multiple Fluorescent Labeling of Annexin-V Probe
Annexin-V can be labeled with different fluorescent groups including PE, FITC, Alexa Fluor 488, etc., targeting the externalization of PS on cell membranes. Emitting green or red fluorescence signals under different excitation and emission channels, it can be used in combination with nuclear probes and others for multi-color cell staining.
Figure 3a. Annexin-V-Fluor647 (in red) stained cells, Source: Reference.
Figure 3b. Annexin-V-FITC (Green) Stained Cells, Source: Reference
2. High Sensitivity and Specificity of Annexin-V Probe
At nanomolar concentration levels, Annexin-V can selectively identify and label early apoptotic cells with externalized PS, without labeling other DNA or RNA, enabling the detection of minimal amounts of apoptotic cells.
3. Low Background Interference and Strong Stability
There is no background interference from other fluorescent colors, resulting in clear staining. Moreover, the performance remains stable across different batches.
4. Comparative Cost-effectiveness of Arcegen Annexin-V Probe to Imported Products
Under the same specifications, the price difference between Arcegen and imported Annexin-V probes is compared.
Figure 4. Price Comparison of Annexin-FITC Products between Arcegen and T* Imports (Specification: 50 T)
In addition, during early apoptosis, the decrease in mitochondrial membrane potential results in changes in membrane permeability. JC-1 dye can detect changes in mitochondrial membrane potential. In normal mitochondria, JC-1 emits strong red fluorescence. However, in the early stages of apoptosis, due to the decrease or loss of membrane potential, JC-1 produces green fluorescence. The enhancement or reduction of fluorescence can reflect an increase or decrease in the electronegativity of the mitochondrial inner membrane.