UltraBio™ Streptavidin Magnetic Beads (1 μm) are prepared by chemically immobilizing streptavidin onto polymeric magnetic microspheres (MagPoly Beads). Utilizing the interaction between biotin and streptavidin ligands, these beads can capture immobilized biotin or biotinylated substances such as proteins and antibodies.
Parameter
| Indicator
|
Matrix
| Polymeric magnetic microspheres
|
Ligand
| Streptavidin
|
Bead Concentration
| 10 mg/mL
|
Particle Size
| 1 μm |
Binding Capacity
| ＞20 μg biotinylated IgG per mg beads
|
Storage
| 2-8℃ (20mM Tris, 0.01% Tween-20, 0.05% KroVin300, pH7.4） |
Instructions for Use:
The following protocol takes 100 μL of UltraBio™ Streptavidin Magnetic Beads (1 μm) per reaction as an example. The bead dosage can be increased or decreased as required.
ⅠReagent Preparation
1. Nucleic acid sample (Buffer Ⅰ): 10 mM Tris-HCl (pH 7.5), 1 mM EDTA, 1 M NaCl, 0.01%~0.1% Tween-20
2. Antibody/protein sample (Buffer Ⅱ): 1× PBS (pH 7.4) containing 0.05% Tween-20. 0.01%~0.1% BSA may be added if needed.
Note: The above are recommended buffer formulations. Adjust the salt concentration and pH according to specific experimental requirements.
ⅡCapture of Biotinylated Molecules
1. Capture of Nucleic Acids
① Invert or vortex the streptavidin magnetic beads to mix thoroughly.
② Transfer 100 μL beads into a new centrifuge tube. Place the tube on a magnetic separator. Once the solution turns clear, aspirate and discard the storage solution with a pipette.
③ Remove the tube from the separator, add 1 mL Buffer Ⅰ, and vortex fully to resuspend the beads. Place the tube back on the magnetic separator until the solution is clear, then aspirate the supernatant. Repeat the washing step 3 times.
Note: If the bead volume taken in Step (2) exceeds 1 mL, add Buffer Ⅰ of the same volume as the beads.
④ Add 500 μL prepared nucleic acid sample (biotinylated nucleic acid diluted with Buffer Ⅰ) to reach a bead concentration of 2 mg/mL. Vortex to fully resuspend the beads. Place the tube on a rotator and incubate with rotation at room temperature for 30 minutes. The incubation time can be adjusted as needed.
⑤ After incubation, place the tube on the magnetic separator and wait for the solution to clear. Aspirate the supernatant, which is recommended to be transferred to a new tube for subsequent quantification of bound nucleic acids. Wash the beads 3 times following the procedure in Step (3).
⑥ Resuspend the beads with an appropriate low-salt buffer based on downstream experimental requirements. The capture of biotinylated nucleic acids is now complete, and the beads are ready for subsequent procedures.
⑦ The amount of bound nucleic acids is calculated as follows:
Bound nucleic acid mass = (Initial concentration − Final concentration) × Total reaction volume
2. Capture of Antibodies/Proteins
① Invert or vortex the streptavidin magnetic beads to mix thoroughly.
② Transfer 100 μL beads into a new centrifuge tube. Place the tube on a magnetic separator. Once the solution turns clear, aspirate and discard the storage solution with a pipette.
③ Remove the tube from the separator, add 1 mL Buffer Ⅱ, and vortex fully to resuspend the beads. Place the tube back on the magnetic separator until the solution is clear, then aspirate the supernatant. Repeat the washing step 3 times.
Note: If the bead volume taken in Step (2) exceeds 1 mL, add Buffer Ⅱ of the same volume as the beads.
④ Add 1 mL prepared antibody/protein sample (biotinylated antibody/protein diluted with Buffer Ⅱ) to reach a bead concentration of 1 mg/mL. Vortex to fully resuspend the beads. Place the tube on a rotator and incubate with rotation at room temperature for 60 minutes. The incubation time can be adjusted as needed.
⑤ After incubation, place the tube on the magnetic separator and wait for the solution to clear. Aspirate the supernatant, which is recommended to be transferred to a new tube for subsequent quantification of bound antibodies/proteins. Wash the beads 5 times following the procedure in Step (3).
⑥ Resuspend the beads with Buffer Ⅱ or other suitable buffers based on downstream experimental requirements. The capture of biotinylated antibodies/proteins is now complete, and the beads are ready for subsequent procedures.
⑦ The amount of bound antibodies/proteins is calculated as follows:
Bound antibody/protein mass = (Initial concentration − Final concentration) × Total reaction volume
Precautions:
1. Do not freeze the magnetic beads.
2. Fully resuspend and homogenize the beads before pipetting. Avoid bubble generation during operation.
3. Optimize experimental parameters (including incubation time, buffer formulation, binding capacity, etc.) according to different experimental applications.
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