| Description | Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric Annexins are a family of calcium-dependent phospholipid-binding proteins that preferentially bind phosphatidylserine (PS). Under normal physiologic conditions, PS is predominantly located in the inner leaflet of the plasma membrane. Upon initiation of apoptosis, PS loses its asymmetric distribution across the phospholipid bilayer and is translocated to the extracellular membrane leaflet marking cells as targets of phagocytosis. Once on the outer surface of the membrane, PS can be detected by fluorescently labeled Annexin V in a calcium-dependent manner. In early-stage apoptosis, the plasma membrane excludes viability dyes such as 4',6-diamidino-2-phenylindole (DAPI）, propidium iodide (PI), 7-AAD. These cells will stain with Annexin V but not a viability dye, thus distinguishing cells in early apoptosis. However, in late stage apoptosis, the cell membrane loses integrity thereby allowing Annexin V to also access PS in the interior of the cell. A viability dye can be used to resolve these late-stage apoptotic and necrotic cells (Annexin V, viability dye-positive) from the early-stage apoptotic cells (Annexin V positive, viability dye-negative). This kit is suitable for the identification and enumeration of dead cells, such as apoptotic or necrotic cells, by flow cytometry.A1456534Components20 T50 T100 TStorageQuantity Per TestA1456534A10× Annexin V Binding Buffer5 mL10 mL20 mL2-8℃200 µL 0.5-1.0 × 10⁵ cellsA1456534BAnnexin V -APC100 µL250 µL500 µL2-8℃. Store in the dark.5 µL 0.5-1.0 × 10⁵ cellsA1456534CDAPI Staining Solution (25 µg/mL)20 µL50 µL100 µL2-8℃. Store in the dark.1 µL 0.5-1.0 × 10⁵ cellsNote: The recommended number of cells to stain per test is 0.5-1.0 × 10⁵ cells.Precautions1. Please try to avoid light when using to slow down the quenching of fluorescence.2. DAPI Solution is toxigenic and mutagenic; handle with care.3. Due to the calcium dependence of the Annexin V:PS interaction, it is critical to avoid buffers containing EDTA or other calcium chelators during Annexin V experiments.Instruction for use 1. Dilute 10X Binding Buffer to 1X using distilled water (1 mL 10X Binding Buffer + 9 mL ddH2O).2. Wash cells twice with cold PBS and then resuspend the desired amount of cells in Annexin V Binding Buffer at a concentration of 0.5- 1.0 × 10⁶ cells /mL.3. Add 5 µL of Annexin V-APC and 1 µL of DAPI staining solution to 100 µL of cell suspension.4. Add 100 µLof 1x Binding Buffer to each assay. Gently vortex the cells and incubate for 10 min at RT (25°C) in the dark.5. Analyze by flow cytometry within 1 hr... Read More | Inquire | Annexin V ( annexin-V ) is a Ca2 + dependent phospholipid binding protein with a molecular weight of 35-36 KD, which can selectively bind to phosphatidylserine ( PS ). Phosphatidylserine ( PS ) is mainly distributed in the inner side of the cell membrane, that is, the side adjacent to the cytoplasm.Annexin V ( annexin-V ) is a Ca2 + dependent phospholipid binding protein with a molecular weight of 35-36 KD, which can selectively bind to phosphatidylserine ( PS ). Phosphatidylserine ( PS ) is mainly distributed in the inner side of the cell membrane, that is, the side adjacent to the cytoplasm. In the early stage of apoptosis, different types of cells will turn phosphatidylserine out to the cell surface and expose to the extracellular environment. At this time, using Annexin V labeled with fluorescent protein PE, that is, Annexin V-PE, combined with phosphatidylserine ( PS ), the eversion of phosphatidylserine, an important feature of apoptosis, can be directly detected by flow cytometry. Normal cells will not be stained by Annexin V-PE, apoptotic or necrotic cells will be stained by Annexin V-PE. Annexin V-PE can be used in combination with partially non-permeable nuclear dye ( 7-AAD / PI ) to distinguish cells at different stages of apoptosis. RedNucleus II provided in this kit is a far-red dye that belongs to an anthraquinone compound and cannot penetrate the intact cell membrane of living cells and early apoptotic cells. It is non-permeable, but can quickly stain the nucleus / dsDNA in dead and permeable cells. RedNucleus II is an ideal substitute for propidium iodide ( PI ) and 7-AAD.Combined with Annexin V-PE, it has better spectral characteristics without compensation regulation : it is not excited by ultraviolet light and does not overlap with PE / PE homologues, so it can be combined with FITC, PE and purple fluorescent dyes for multicolor analysis. When combined with Annexin V-PE, RedNucleus II was excluded from living cells and early apoptotic cells, while late apoptotic cells and dead cells were double-positive for Annexin V-PE and RedNucleus II. Annexin V-PE / RedNucleus II apoptosis detection kit can be detected by flow cytometry or other fluorescence detection equipment. Components: Components A598354(10T) A598354(50T) A598354(100T) A. 1×Annexin V Combining buffer solution 10 mL 50 mL 50 mL×2 B. Annexin V-PE 50 µL 250 µL 500 µL C. RedNucleus II 100 µL 500 µL 1 mLProduct parameters：Annexin v-pe:ex/em=488/578 nmrednucleus ii:ex/em=635/695 NMUsage method:1. Experimental design: Blank tube: Negative control group cells, without Annexin V-PE/RedNucleus II. Used to regulate voltage.Single staining tube: Positive control group cells were treated with Annexin V-PE alone/RedNucleus II alone. Used for adjusting compensation.Detection tube: Add Annexin V-PE/RedNucleus II to the processed cells. After adjusting the voltage compensation using blank tubes and single dye tubes, obtain the required flow data.2. Collect cells(1) For suspended cells:a. After inducing cell apoptosis, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, collect the cells, gently resuspend the cells in PBS, and count them.Note: PBS resuspension cannot be omitted. The process of PBS resuspension also serves to wash cells, ensuring the subsequent binding of Annexin V-PE.b. Take 5 × 104-1 × 105 resuspended cells, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, and add 100 µ L of 1 × Annexin V binding buffer to gently resuspend the cells. c. Add 5 µ L Annexin V-PE and mix gently.d. Add 5 µ L of RedNucleus II staining solution and mix gently.e. Incubate at room temperature (20-25 º C) in the dark for 15 minutes. Aluminum foil can be used to avoid light. During the incubation process, cells can be resuspended 2-3 times to improve staining efficiency.(2) For adherent cells:a. Suck out the cell culture medium into a suitable centrifuge tube, wash the adherent cells with PBS once, and add an appropriate amount of trypsin cell digestion solution (without EDTA) to digest the cells. Incubate at room temperature until gently blowing can remove the trypsin cell digestion solution when the adherent cells are blown down. Overdigestion of pancreatic enzymes should be avoided.Note: For adherent cells, the trypsin digestion step is crucial. If the trypsin digestion time is too short, cells need to be blown hard to detach, which can easily cause damage to the cell membrane and lead to false positives of cell necrosis; If the digestion time is too long, it can also cause cell membrane damage and false positives of cell necrosis, and even affect the binding of phosphatidylserine and Annexin V-PE on the cell membrane, thereby interfering with the detection of cell apoptosis.b. Add the cell culture medium collected in the previous step, gently blow down the cells, transfer them to a centrifuge tube, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, collect the cells, gently resuspend the cells in PBS and count them.Note: Adding the cell culture medium from the previous step is very important. On the one hand, it can collect cells that have already been suspended and undergone apoptosis or necrosis. On the other hand, the serum in the cell culture medium can effectively inhibit or neutralize residual trypsin. The residual trypsin will digest and degrade the subsequently added Annexin V-PE, leading to staining failure.c. Take 5 × 104-1 × 105 resuspended cells, centrifuge at 1000 rpm for 5 minutes, discard the supernatant, and add 100 µ L of 1 × Annexin V binding buffer to gently resuspend the cells. d. Add 5 µ L Annexin V-PE and mix gently.e. Add 5 µ L of RedNucleus II staining solution and mix gently.f. Incubate at room temperature (20-25 º C) in the dark for 15 minutes. Aluminum foil can be used to avoid light. During the incubation process, cells can be resuspended 2-3 times to improve staining efficiency.3. Result analysis:(1) Flow cytometry detection:a. After incubation, 400 µ L of 1 × Annexin V binding buffer can be directly added to resuspend the cells, and immediately detected on the machine. Annexin V-PE is excited by 488 nm/566 nm laser, and the fluorescence emission spectrum is detected at 578 nm (BL2 (FL2)/YL1 channel), while the RedNucleus II channel emission spectrum is approximately at 695 nm (RL1 (FL4) channel).b. On the scatter plot of the bivariate flow cytometer, live cells are shown in the lower left quadrant, which is (Annexin V-PE -/RedNucleus II -); The lower right quadrant represents early apoptotic cells, which are (Annexin V-PE+/RedNucleus II -); The upper right quadrant represents necrotic and late stage apoptotic cells, which are (Annexin V-PE+/RedNucleus II+); The upper left quadrant displays naked nuclear cells, which are (Annexin V-PE -/RedNucleus II+).(2) Fluorescence microscopy detection:a. Centrifuge at 1000 rpm for 5 minutes, collect cells, and gently resuspend them in 400 µ L of 1 × Annexin V binding buffer. Transfer the cells to a 96 well plate and settle for a moment or perform cell smear, then observe under a fluorescence microscope.b. Annexin V-PE is compatible with PE filters. RedNucleus II can use a far red long pass filter.Matters needing attention：1. please centrifuge the product to the bottom of the tube immediately before use, and then conduct subsequent experiments. 2. to reduce the process of apoptosis, the incubation process can be operated on ice, but the incubation time should be extended to at least 30 min. 3. as apoptosis is a rapid process, it is recommended that samples be analyzed within 1 h after staining. 4. for adherent cells, digestion is a key step. If there are floating cells when adherent cells induce apoptosis, the floating cells and adherent cells should be collected and stained. Handle adherent cells with care to avoid artificial damage to cells. The trypsin digestion time is too short, and the cells need to be blown hard to fall off, which is easy to cause damage to the cell membrane and excessive intake of rednucleus II; If the digestion time is too long, the cell membrane is also prone to damage, and even affect the binding of phosphatidylserine and annexin v-pe on the cell membrane. When digesting, spread pancreatin on the bottom of the well plate, fully contact the pancreatin with the cells when shaking gently, then pour out most of the pancreatin, use the remaining small amount of pancreatin to digest for a period of time, and terminate when the gap between cells increases and the bottom of the bottle is spotted. Try not to use EDTA in the digestive juice, which will affect the binding of annexin V to PS. 5. after the adherent cells are digested with trypsin, it is recommended to stain after recovering in the optimal culture conditions and medium for about 30 min to avoid false positives. 6. in order to avoid losing cells when washing cells, you can use a large tip over a small tip to aspirate. 7. the optimal concentration of dye is determined by the specific experimental requirements. 8. fluorescent dyes have quenching problems. Please try to avoid light during storage and use to slow down fluorescence quenching. 9. for your safety and health, please wear experimental clothes and disposable gloves.Scope of application：Early apoptosis detection, annexin V Kit... Read More | The content of this cell is too long for an XLSX file (more than 32767 characters). Please use the CSV format for this export | Inquire |