Product Information
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Streptavidin Magnetic Beads (beads-STA) is designed as a rapid and simple tool for immunoprecipitation, purification/depletion assay, and other applications. Biotinylated molecules, such as nucleic acids, peptides and proteins can bind to Streptavidin Magnetic Beads easily. By applying magnetic attraction, Streptavidin Magnetic Beads-molecules complex will be temporarily immobilized at tube wall, so the other parts in supernatant can be removed easily and efficiently. The binding capacity of Streptavidin Magnetic Beads is about 12 nmole biotin per mL.
Binding characteristics
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Specifications
| Core | Iron Oxide (Fe3O4) |
| Layer | Dextran |
| Surface protein | Streptavidin |
| Mean Diameter of Particles | ~1 μm |
| Storage Buffer | pH 7.4 PBS, 0.02% Tween 20, 0.09% sodium azide and 10% glycerol |
| Storage temp. | 2 ~ 8 ℃ |
| Capacity | 12 nmole biotin/ mL |
Material supplied
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Beads-STA providesFe3O4 beads coated with dextran of anaverage ~1 μm in diameter. Streptavidin, about 60 kDa, is coupled covalently to dextran. Beads are supplied in phosphate buffered saline, pH 7.4, containing 0.02% Tween-20, 0.09% sodium azide and 10% glycerol.
Additional material required
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• Beads-STA
Washing Buffer:
- Target molecules: Nucleic acids; Proteins/peptides/others
- Washing Buffer: TE buffer; PBS buffer (pH 7.4) with 0.02% Tween 20
• Magnetic stand: Magstand is suggested for the best performance
• Tilt rotation device or vortexer
• Eppendorf tubes & pipettes
Protocol
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Preparation of Beads-STA for use
1. Resuspend the Beads-STA thoroughly by pipetting or vortexing the vial.
2. Transfer an adequate volume of Beads-STA to a clean tube.
3. Place the tube on the magnetic stand for 30-60 seconds to immobilize the beads at the tube wall.
4. Discard the supernatant by aspiration with a pipette.
5. Remove the tube from the magnetic stand.
6. Add 200 μL Washing Buffer and resuspend the beads by pipetting.
7. Place the tube on the magnetic stand for 30-60 seconds to immobilize the beads at the tube wall.
8. Discard the supernatant, then remove the tube from the magnetic stand.
9. Repeat steps 6-8 twice.
10. The beads are now ready for binding of biotinylated molecules.
NOTE: Beads-STA contains 0.09% NaN₃, so we strongly recommend washing the beads at least three times before use.
Binding of Biotinylated Molecule
11. Add an adequate amount of biotinylated molecule sample to the tube from step 10.
12. Incubate with tilt rotation for 30 minutes at room temperature.
13. Add 200 μL Washing Buffer and resuspend the beads by pipetting.
14. Place the tube on the magnetic stand for 30-60 seconds to immobilize the beads at the tube wall.
15. Discard the supernatant, then remove the tube from the magnetic stand.
16. Repeat steps 13-15 three times to remove unbound molecules.
17. Finally, resuspend the beads-biotinylated molecule complex in Washing Buffer.
Elution of Biotinylated Molecule
18. For elution of biotinylated nucleic acids from Beads-STA:
18.1 Remove Washing Buffer from the tube.
18.2 Add 200 μL 10 mM EDTA (pH 8.2) solution with 95% formamide to the tube, then resuspend the Beads-STA evenly.
18.3 Incubate the tube at 65°C for 5 minutes.
18.4 Place the tube on the magnetic stand for 30-60 seconds to immobilize the beads at the tube wall.
18.5 Collect the supernatant into a new tube.
19. For elution of biotinylated proteins from Beads-STA:
19.1 Remove Washing Buffer from the tube.
19.2 Add 200 μL Washing Buffer (PBS) with 0.1% SDS to the tube, then resuspend the Beads-STA evenly.
19.3 Incubate the tube at 95°C for 5 minutes.
19.4 Place the tube on the magnetic stand for 30-60 seconds to immobilize the beads at the tube wall.
19.5 Collect the supernatant into a new tube.
Troubleshooting
| Troubles | Solutions |
| Biotinylated molecule binding is low. | 1. Make sure the beads are suspended thoroughly before use. 2. Mix beads and sample thoroughly and continuously with either a tilt rotation device or a vortexer. |
| Beads do not collect on the magnet. | 1. Make sure the tube is in direct contact with the magnetic stand. 2. Use the Magstand magnetic stand for best performance. |