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| Product Name | Streptavidin Magnetic Beads (1 µm) |
| Catalog No. | MAGBEA-0008 |
| Description | One-micrometer superparamagnetic beads covalently coated with recombinant streptavidin for high-affinity capture of biotinylated biomolecules. The streptavidin is coupled through a stable covalent linkage that minimizes protein leaching under harsh binding and washing conditions. With four biotin-binding sites per streptavidin tetramer and a dissociation constant of approximately 10^-15 M, these beads provide near-irreversible capture of biotinylated antibodies, oligonucleotides, peptides, and other ligands for immunoprecipitation, protein interaction analysis, and molecular diagnostics. |
| Intended Use | Capture and purification of biotinylated antibodies, antigens, oligonucleotides, peptides, and PCR products for immunoprecipitation, ChIP, pull-down assays, aptamer selection, DNA-protein interaction studies, and chemiluminescence immunoassay development. |
| Principle / Technology | Recombinant streptavidin (tetramer, ~53 kDa) is covalently coupled to the surface of 1 µm carboxyl-functionalized polymer beads via EDC/NHS amide bond formation. Each streptavidin tetramer presents four biotin-binding pockets with extraordinarily high affinity (Kd ~10^-14 to 10^-15 M). Biotinylated ligands bind essentially irreversibly under physiological conditions, forming a stable non-covalent complex resistant to high salt, detergents, denaturants, and moderate pH extremes. The superparamagnetic core enables rapid bead capture and efficient washing. |
| Detection Method | DLS and Coulter counter for size; BCA assay for streptavidin coating density; biotin-4-fluorescein or biotin-HRP binding assay for binding capacity and activity; HABA (4'-hydroxyazobenzene-2-carboxylic acid) displacement assay for biotin-binding site quantification; BSA non-specific binding assay; SDS-PAGE for streptavidin leaching analysis |
| Sample Type | Biotinylated molecules including antibodies, peptides, oligonucleotides, proteins, enzymes, small molecule haptens, and nucleic acid probes; biotinylated PCR products; in vivo biotinylated proteins from BirA-expressing cells; chemical biotinylation using NHS-biotin or sulfo-NHS-biotin reagents |
| Performance Range / Specifications | Particle diameter: 1.0 ± 0.1 µm; streptavidin coating density: 5-15 µg streptavidin per mg beads; biotin binding capacity: 400-1200 pmol free biotin per mg beads; biotinylated IgG binding: 10-30 µg per mg beads; biotinylated oligo (25-mer) binding: 200-800 pmol per mg beads; non-specific binding: <2 µg BSA/mg; KD (biotin): ~10^-15 M; separation time: <10 seconds |
| Sensitivity / LOD | Detection of <1 fmol biotinylated target per mg beads; single biotin moiety sufficient for capture (no multivalent requirement); binding of biotinylated molecules at concentrations as low as 10^-12 M; PCR product capture from reactions containing <1 ng template |
| Specificity | Streptavidin-biotin interaction is among the strongest known non-covalent biological interactions; binding specificity >10^6-fold over non-biotinylated molecules; minimal cross-reactivity with other vitamins and cofactors; no binding of non-biotinylated proteins, nucleic acids, or small molecules; recombinant streptavidin has no carbohydrate modification, eliminating non-specific lectin binding |
| Reaction Conditions / Protocol | Transfer desired bead volume to tube; wash twice with binding/wash buffer (PBS pH 7.4, 0.05% Tween-20); add biotinylated ligand in binding buffer; incubate at room temperature for 30 minutes with end-over-end rotation; wash beads 2-3 times with binding buffer to remove unbound ligand; use directly for target capture or wash and resuspend in appropriate buffer; for biotinylated antibody capture, typical incubation: 30-60 minutes at room temperature; capacity assessment by flow cytometry or spectrophotometric methods |
| Components / Formulation | Streptavidin-coated superparamagnetic polymer beads, 1.0 µm, 10 mg/mL in PBS pH 7.4 with 0.02% sodium azide and 0.1% BSA as stabilizer; recombinant streptavidin expressed in E. coli, chromatographically purified; no native streptavidin (Streptomyces avidinii) used |
| Storage Conditions | 2-8°C in sealed container; do not freeze (freezing denatures streptavidin and causes aggregation); protect from light; vortex gently before use (30 seconds, avoid foaming); use aseptic technique; streptavidin is stable under recommended conditions |
| Shelf Life | 18 months at 2-8°C; streptavidin activity monitored by biotin-binding assay at 0, 6, 12, and 18 months; protein stabilizer (BSA) included to extend shelf life; opened container: use within 6 months with proper handling |
| Package Specifications | 1 mL, 5 mL, 10 mL at 10 mg/mL; trial sizes available; bulk packaging for OEM upon request; supplied in polypropylene tubes with secure O-ring caps |
| Product Form | Dark brown to black uniform suspension; homogeneous after gentle vortexing; no visible aggregates or protein precipitate; supernatant after magnetic separation is clear, not turbid; recombinant streptavidin verified by SDS-PAGE and Western blot |
| Quality Control | Each lot: streptavidin coating density (BCA), biotin-binding activity (HABA displacement and biotin-HRP), biotinylated IgG capture capacity, non-specific protein binding, streptavidin leaching (SDS-PAGE/silver stain of incubation supernatant), endotoxin (<0.1 EU/mg), particle size, magnetic separation, sterility; functional validation by immunoprecipitation of biotinylated target protein |
| Key Features | Recombinant streptavidin for consistent quality and minimal non-specific binding; near-irreversible biotin binding (Kd ~10^-15 M); stable covalent streptavidin linkage; no leaching under denaturing conditions; sugar-free streptavidin eliminates lectin background; validated for ChIP, IP, pull-down, and CLIA applications; rapid magnetic separation |
| Purity | >95% streptavidin purity by SDS-PAGE; no protease or avidin contamination; endotoxin <0.1 EU/mg; streptavidin leaching <0.1% after 24-hour incubation at 37°C in PBS; free biotin <0.01% as measured by HABA assay |
| Concentration | 10 mg/mL bead concentration; streptavidin 5-15 µg/mg; exact coating density in lot certificate; biotin binding capacity 400-1200 pmol/mg |
| Activity / Unit Definition | Biotin binding: 400-1200 pmol/mg (free biotin); biotinylated BSA binding: 8-20 µg/mg; biotinylated IgG binding: 10-30 µg/mg; biotinylated oligonucleotide: 200-800 pmol/mg; activity >90% after 18 months storage |
| Molecular Weight | Streptavidin tetramer: ~53 kDa (13.3 kDa per monomer × 4 subunits); bead molecular weight not applicable for polymeric composite |
| Source / Origin | Recombinant streptavidin expressed in E. coli BL21(DE3) under T7 promoter, purified by affinity chromatography and ion exchange; magnetic beads are fully synthetic polymer-magnetite composite; all other reagents are synthetic or recombinant; no animal-derived components; TSE/BSE free |
| pH Range / Optimal pH | Binding stability: pH 4.0-10.0; optimal biotin binding: pH 6.0-8.5; irreversible streptavidin denaturation: pH <2.0 or >12.0; biotin-streptavidin complex stable across pH 2-12; bead preservation: pH 3.0-12.0 |
| Shipping Conditions | Cold pack shipping recommended (2-8°C); ambient temperature acceptable for short transit (<1 week) with cold packs; do not freeze under any circumstances; shipped in insulated container for summer months; non-hazardous |
| Expiration Date / Stability | 18 months at 2-8°C; streptavidin activity >90% retained at 18 months; real-time stability program monitors binding capacity; no significant protein leaching throughout shelf life; BSA stabilizer maintains streptavidin conformation; opened product: 6 months at 2-8°C |
| Regulatory / Compliance | For research use and further manufacturing; suitable for IVD component use upon end-user validation; recombinant product, no animal origin; manufactured in ISO 9001 facility; certificate of analysis per lot; DMF filing available |
| Compatibility | Biotinylated ligands from all major suppliers; compatible with common IP/IP-MS buffers including RIPA, NP-40, Triton X-100; tolerant to 2 M NaCl, 6 M urea, 1% SDS; not compatible with biotin-containing media and supplements during target capture; avoid β-mercaptoethanol above 5% (weakens biotin binding); compatible with KingFisher and other automated platforms |
| Recommended Buffer System | Storage buffer: PBS pH 7.4, 0.02% NaN3, 0.1% BSA; binding/wash buffer: PBS pH 7.4 with 0.05% Tween-20; elution: 8 M guanidine HCl pH 1.5 or boiling in SDS loading buffer (denatures streptavidin, releases biotinylated ligand); for native elution: 2 mM free biotin in PBS (requires competitive displacement, not quantitative) |
| Application Notes / Precautions | Pre-wash beads to remove BSA stabilizer before biotinylated ligand capture; insufficient washing after ligand binding may result in high background in pull-down assays; streptavidin is robust—extensive washing with stringent buffers improves signal-to-noise; for quantitative capture, titrate biotinylated ligand to avoid bead overloading; avoid using biotin-containing blocking reagents (non-fat milk contains biotin); for ChIP, pre-block beads with salmon sperm DNA and BSA |
| Batch-to-Batch Consistency | Streptavidin coating density CV <12%; biotin binding capacity CV <10%; biotinylated IgG capture CV <15%; particle size CV <10%; endotoxin consistently <0.1 EU/mg; all lots functionally tested in IP workflow |
For research use only, not for clinical use.
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