BSA Solution — 5% to 30%.
Ready to use.
Bovine Serum Albumin Fraction V, ≥97% purity — sterile filtered, ready-to-use solutions in PBS. For ELISA blocking, Western blot, lateral flow assay development, IVD reagent manufacturing and cell culture. Custom concentrations on request. Ships at ambient temperature. No minimum order.
Fraction V BSA — ≥97% Purity
Fraction V refers to the fifth fraction of the Cohn cold-ethanol fractionation process — the fraction richest in albumin. Fraction V BSA achieves ≥97% albumin purity by electrophoresis and is the standard grade for cell culture supplementation, immunoassay blocking and diagnostics reagent development. It is distinct from lower-purity technical-grade BSA preparations. SeamlessBio BSA solutions are prepared exclusively from Fraction V BSA.
Molecular weight: ~66 kDa. Isoelectric point: 4.7. Negative charge at physiological pH enables BSA to bind and transport water, salts, fatty acids, vitamins and hormones between tissues — the same binding capacity that makes it the standard blocking reagent and stabiliser in immunoassay systems.
PBS Buffer — pH 7.2–7.4 (Standard)
Standard buffer: Phosphate-Buffered Saline (PBS), pH 7.2–7.4. This is compatible with the vast majority of ELISA, Western blot, immunofluorescence and cell culture applications. The physiological pH range ensures BSA remains in its native conformation and does not precipitate in culture medium or assay buffer.
Alternative buffer systems available on request: HEPES buffer, Tris-HCl (pH 7.5 or 8.0), carbonate-bicarbonate buffer (for conjugation reactions), water for injection (WFI). Specify your required buffer and pH at time of order — lead time 5–7 business days for non-standard buffers.
Low Endotoxin Specification — Available on Request
Standard BSA solution: endotoxin not specified (suitable for most immunoassay and general cell culture applications). Low Endotoxin specification (<1 EU/mg, LAL method) available on request for GMP process development, vaccine adjuvant applications and endotoxin-sensitive cell culture systems including PBMC, dendritic cell and macrophage assays.
For applications where endotoxin control is critical — particularly cell therapy process development — specify Low Endotoxin at time of order. Additional testing and certificate of endotoxin result included. Lead time may apply.
Ambient Temperature Shipping — Refrigerated Storage After Receipt
BSA solution ships at ambient temperature (RT) — no cold chain required, reducing shipping cost and complexity. Store at +2°C to +8°C after receipt. Do not freeze — freezing causes protein aggregation and reduces solution clarity and binding capacity. Shelf life: 36 months from production date at correct storage. After opening, use within 4 weeks and keep refrigerated.
For long-term or ambient-temperature storage requirements, BSA powder offers significantly better stability. See BSA Powder Low Endotoxin.
Custom Concentrations & Buffer Systems
In addition to standard concentrations (5%, 10%, 15%, 20%, 25%, 30%), SeamlessBio prepares BSA solutions in custom concentrations and buffer systems on request. Specify your required concentration (%), buffer system (PBS, HEPES, Tris-HCl, carbonate, WFI), pH, and required volume. We confirm feasibility and lead time within 1–2 business days.
Batch reservation for ongoing production supply is available at no cost. Useful for IVD manufacturers who have validated a specific BSA lot and concentration for calibrator or control production — reserve the full programme lifecycle requirement from day one to avoid mid-production lot changes.
Documentation Package
Included with every order: Certificate of Analysis (CoA) with lot-specific purity, pH and sterility confirmation; Material Safety Data Sheet (MSDS/SDS). On request: low endotoxin test result (LAL), BSE/TSE statement (bovine source declaration), ISO 13485 manufacturer certificate, extended analytical package for IVD regulatory submissions.
BSA 5% Solution
Standard blocking concentration — ready to use directly as blocking buffer in PBST or TBST.
- ELISA blocking (5% in PBST/TBST)
- Western blot membrane blocking
- Antibody dilution buffer
- General cell culture supplement
BSA 10% Solution
Versatile stock — use directly or dilute. The most flexible starting concentration for lab use.
- Immunofluorescence blocking
- Antibody stabilisation and storage
- Cell culture supplement
- IVD reagent development
BSA 15% Solution
Higher protein density for enzyme stabilisation and lateral flow assay component formulation.
- Enzyme stabilisation
- Antibody formulation buffers
- Point-of-care diagnostics
- Lateral flow assay development
BSA 20% Solution
High-concentration stock for efficient storage and dilution to any working concentration.
- High-throughput lab stock solution
- IVD calibrator manufacturing matrix
- Protein formulation — pharma
- Cryoprotection buffers
BSA 25% Solution
On request — for specialised diagnostic and pharmaceutical applications requiring elevated protein concentrations.
- High-protein diagnostic reagents
- Custom assay matrix formulation
- Pharmaceutical process development
- Available with individual specification
BSA 30% Solution
Maximum standard concentration — equivalent to Biowest A0296 and comparable market standards. For highest-density applications.
- Biotinylation & conjugation reactions
- High-density protein for diagnostics
- Pharmaceutical formulation
- Cell cryopreservation protocols
ELISA Blocking
5% BSA in PBST or TBST — the standard blocking buffer for ELISA assays. Preferred over milk for phospho-protein detection. Ready to use directly from the 5% solution.
Western Blot Blocking
5% BSA in TBST for Western blot membrane blocking — particularly preferred when the primary antibody targets phosphorylated proteins, where milk proteins cause background.
Lateral Flow & IVD
15–20% BSA for conjugate pad and nitrocellulose blocking in lateral flow assay development. IVD calibrator and control matrix from 10% to 30% depending on target analyte concentration.
IVD Calibrator Manufacturing
Defined protein concentration provides a consistent matrix for calibrator and control production. Batch reservation available — avoids mid-production lot changes and associated change control costs.
Cell Culture Supplement
BSA as a serum supplement or partial FBS replacement in certain protocols — particularly for fatty acid delivery (use fatty acid-free BSA pre-loaded with defined fatty acids).
Cryoprotection
20–30% BSA in cryoprotection formulations for cell and tissue preservation. Reduces ice crystal formation and osmotic stress during freeze-thaw cycles.
6 standard concentrations from one source — no switching supplier when you need a different concentration
Ships at ambient temperature — no dry ice, no cold chain surcharges
No minimum order — from 10 mL evaluation to bulk litres
Custom concentrations and buffer systems — specify your exact requirements
Low endotoxin specification available — for GMP process development and cell therapy
Batch reservation for IVD manufacturing — no prepayment, EU stock, call-off as needed
Which BSA concentration should I use for ELISA blocking?
1–5% BSA in PBST (PBS + 0.05% Tween-20) or TBST is the standard for blocking non-specific binding sites in ELISA. The 5% solution can be used directly as blocking buffer without further dilution. For Western blot applications, 5% BSA in TBST is preferred over skimmed milk when the primary antibody targets phosphorylated proteins — milk caseins are phosphorylated and generate high background signal with phospho-specific antibodies.
What is Fraction V BSA and why does it matter?
Fraction V refers to the fifth fraction obtained in the Cohn cold-ethanol fractionation process — the fraction richest in albumin, typically achieving ≥97% purity. It is the standard grade used in cell culture, immunoassay and diagnostic applications, distinct from lower-purity technical-grade BSA. All SeamlessBio BSA solutions are prepared from Fraction V BSA.
What is the difference between BSA solution and BSA powder?
BSA powder is more economical per gram and flexible in concentration, but requires precise weighing, complete dissolution without foaming, pH adjustment and sterile filtration before use. BSA solution is immediately ready to use, sterile filtered, and batch-tested — eliminating preparation variability. For laboratories with defined concentration requirements and regular BSA usage, ready-to-use solution provides better reproducibility. BSA solution ships at ambient temperature; no cold chain required.
Can I order custom BSA concentrations or buffer systems?
Yes. SeamlessBio prepares BSA solutions in custom concentrations (any percentage between 5% and 30%, or other concentrations on request) and in alternative buffer systems including HEPES, Tris-HCl, carbonate-bicarbonate buffer and water for injection. Contact info@seamlessbio.de with your specification — we confirm feasibility and lead time within 1–2 business days.
How should BSA solution be stored and what is the shelf life?
Store at +2°C to +8°C after receipt. Do not freeze — freezing causes protein aggregation and reduces solution quality. Shelf life is 36 months from production date at correct storage. After opening, use within 4 weeks and keep refrigerated. BSA solution ships at ambient temperature (no cold chain required).
Is BSA solution suitable for GMP or IVD manufacturing applications?
Standard BSA solution is suitable for research and IVD development applications. For GMP or IVD manufacturing, a low endotoxin specification (<1 EU/mg, LAL method) is available on request. Additional GMP documentation including BSE/TSE statements, manufacturer certificates and ISO 13485 certificates can be provided. Contact info@seamlessbio.de with your specific documentation requirements.
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