How does the oriscience annexin V-FITC/PI apoptosis detection kit achieve fast and accurate apoptosis detection by flow cytometry or fluorescence microscopy?
Publish Time: 2025-04-29
Apoptosis is an important physiological process in organisms, involving many aspects such as development, immune response and disease state. Accurate detection of apoptosis is essential for understanding these processes. The oriscience annexin V-FITC/PI apoptosis detection kit provides a fast and convenient method for accurate detection by flow cytometry or fluorescence microscopy.1. Annexin V-FITC binds to PSUnder normal physiological conditions, phosphatidylserine (PS) is mainly located in the inner layer of the cell membrane. However, when cells enter the apoptosis program, PS flips from the inside of the cell membrane to the outside. This phenomenon has become one of the key signs for identifying early apoptotic cells. Annexin V is a calcium-dependent phospholipid-binding protein with a very high affinity for PS. Therefore, during the detection process, Annexin V is labeled with fluorescein isothiocyanate (FITC) to form an Annexin V-FITC complex, which can specifically bind to exposed PS, thereby marking cells in the early stage of apoptosis.2. Propidium iodide (PI) staining to distinguish late apoptosis from necrosisPropidium iodide (PI) is a nucleic acid dye that can specifically bind to double-stranded DNA and produce a strong fluorescent signal. However, due to its large molecule and positive charge, PI cannot penetrate the intact cell membrane and will not be stained in healthy or early apoptotic cells. Only when the cell enters the late stage of apoptosis or necrosis and the integrity of the cell membrane is lost, can PI enter the cell to stain DNA. In this way, by combining Annexin V-FITC and PI, early apoptosis, late apoptosis and necrotic cells can be effectively distinguished.3. Application of flow cytometryFlow cytometry is a powerful single-cell analysis technology that can simultaneously measure multiple parameters of a large number of single cells. When using the oriscience annexin V-FITC/PI apoptosis detection kit, the cells to be tested are first incubated with Annexin V-FITC and PI, and then analyzed by flow cytometry. The instrument determines whether it is labeled with Annexin V-FITC (green fluorescence) or stained with PI (red fluorescence) based on the fluorescence intensity emitted by each cell. Through statistical analysis of the data, the proportion of apoptotic cells at each stage in the cell population can be obtained, so as to fully understand the overall apoptosis of the sample.4. Application of fluorescence microscopyIn addition to flow cytometry, fluorescence microscopy is also one of the commonly used tools for apoptosis detection. In this case, cells treated with Annexin V-FITC and PI can be observed directly on the slide. Under the microscope, green fluorescence indicates early apoptotic cells, while red fluorescence indicates that the cells are in a late apoptotic or necrotic state. This method is not only suitable for single-cell level research, but can also be used for the analysis of tissue sections, helping researchers to more intuitively see the apoptosis of cells in a specific area.5. Interpretation of results and data analysisWhether using flow cytometry or fluorescence microscopy, it is crucial to correctly interpret the experimental results. Normally, cells that have not undergone apoptosis are neither stained by Annexin V-FITC nor by PI; early apoptotic cells are only stained by Annexin V-FITC; late apoptotic or necrotic cells are stained by both. Based on these characteristics, researchers can draw a two-dimensional scatter plot or directly mark the positions of different types of cells in the microscopic image, and then calculate the proportion of cells in each stage.In summary, the oriscience annexin V-FITC/PI apoptosis detection kit provides researchers with a fast, accurate and simple method to detect different stages of cell apoptosis by utilizing the high affinity binding of Annexin V-FITC to PS and the selective staining of DNA by PI, combined with flow cytometry or fluorescence microscopy. This technology not only improves experimental efficiency, but also enhances the reliability and repeatability of the results, which is of great significance for in-depth research on the mechanism of cell apoptosis and the diagnosis and treatment of related diseases.
