BSA, FITC conjugate

Cat. No.: B1509129

GRADE & PURITY Suitable for Immunofluorescence(IF), BioReagent

Panoramica

Fluorescein Isothiocyanate-labeled Bovine Serum Albumin (FITC-BSA) is one of the fluorescent-labeled albumin conjugates launched by Aladdin. The FITC dye exhibits bright green fluorescence properties with excitation/emission wavelengths of 498 nm/517 nm, making it suitable for fluorescence tracing or the development of biological detection systems.Our company offers a diverse range of chemically functionalized and bioconjugated Bovine Serum Albumin (BSA) products, modified with various functional groups or biological moieties. These functionalized BSA products are purified via size exclusion chromatography (SEC) or dialysis to eliminate unreacted molecules, ensuring compatibility with in vitro and in vivo applications.

Specifications:

Form: lyophilized solid ;

Color: Yellow to orange;

Labeling ratio: 5–7 FITC dye molecules per BSA molecule;

Conjugation type: Covalently conjugated through lysine residues;

Excitation/Emission wavelength: 498/517 nm;

Storage Conditions:Store at -20°C, protect from light.

Specifications

Product Name

BSA, FITC conjugate

Sinonimi

BSA, FITC labeled | Albumin from Bovine Serum (BSA), FITC conjugate | Bovine Serum albumin Fr.V, conjugated with FITC | Bovine Serum Albumin-FITC | BSA-FITC

Grado

BioReagent, Suitable for Immunofluorescence(IF)

Specifiche e purezza

BioReagent,Suitable for Immunofluorescence(IF)

Coniugazione

FITC

Eccitazione (nm)

Blue Laser(488nm)

Emissione (nm)

517nm

Ex/Em(nm)

Tipo di molecola

Bioreagenti/Tampone

Product Line

Prodotti biologici

Stoccaggio e spedizione

Ricostituzione

Reconstitute in ultrapure water

Condizioni di conservazione di stoccaggio

Protected from light,Store at -20°C

Spedito in

Ice chest + Ice pads

Stabilità e conservazione

Store at -20°C long term (2 years)

Application Protocols

The product is graded as Suitable for Immunofluorescence (IF). Below are general, literature-based protocols tailored to BSA–FITC. Adjust to your system; refer to CoA/Spec Sheet for any item-specific details.

A. IF calibration and background assessment

1. Prepare serial dilutions (e.g., 50, 10, 2 µg/mL) in PBS, pH 7.4.
2. Spot 5–10 µL onto glass slides, air-dry briefly in the dark, then mount with neutral pH antifade medium.
3. Image using FITC/GFP filters (Ex ~488–495 nm; Em ~510–550 nm). Determine exposure/gain for linear response.

B. Tracer uptake/permeability (fixed cells)

1. Culture cells on coverslips; wash with warm PBS.
2. Incubate with 10–50 µg/mL BSA–FITC in HEPES-buffered saline, 15–60 min at 37 °C (optimize).
3. Wash 3× with buffer. Optionally fix with 4% paraformaldehyde (avoid prolonged fixation in acidic buffers to preserve fluorescence).
4. Mount and image under minimal light.

C. Surface adsorption study

1. Flow 5–20 µg/mL BSA–FITC over material surface in PBS with 0.01% Tween-20.
2. Record fluorescence vs. time to assess adsorption/desorption; regenerate with high-salt or mild detergent if compatible.

Notes

• Include negative controls (buffer only) to assess autofluorescence.
• Protect samples from light; avoid pH <6 during imaging to prevent fluorescein quenching.

Biological Roles

This section provides context from general literature; it does not assign any clinical or therapeutic role to this product.

• BSA (bovine serum albumin):

  • A major serum protein (~66 kDa, literature) responsible for ligand transport (fatty acids, bilirubin), osmotic pressure maintenance, and pH buffering in bovine plasma. Extensively used as a stabilizer, carrier, and blocking agent in biochemical assays due to its abundance and relatively low cost.

• FITC (fluorescein isothiocyanate):

  • A green-emitting xanthene dye that forms thiourea linkages with primary amines on proteins. Exhibits excitation/emission maxima near 494/518 nm (literature) with fluorescence strongly influenced by pH (phenolate formation enhances brightness above pH ~6.4).

• Conjugate behavior (literature):

  • Conjugation localizes multiple fluorophores on a single protein scaffold, enabling strong signals per macromolecule while maintaining aqueous solubility. The microenvironment of each dye (surface exposure, proximity to other dyes) modulates quantum yield and potential self-quenching.

• Utility in biochemistry:

  • Serves as a model macromolecular tracer for transport studies, endocytosis, and permeability due to its defined hydrodynamic size and ready detectability. Provides a non-antigen-specific fluorescent standard to validate imaging systems and assess matrix autofluorescence in the green channel.

Buffer Applications

BSA–FITC is used in aqueous buffer systems; the following guidance is general/literature-based and should be adapted to your protocol.

• Common working buffers:

  • PBS, pH 7.2–7.4: 10–100 mM phosphate, 150 mM NaCl. Maximizes fluorescein brightness in physiological range.
  • TBS, pH 7.4–8.0: 25–50 mM Tris, 150 mM NaCl. Suitable when phosphate interactions are undesirable.
  • HEPES-buffered saline, pH 7.4: 10–50 mM HEPES, 150 mM NaCl; excellent for live-cell compatibility.

• Additives (as appropriate):

  • 0.01–0.05% Tween-20 to reduce surface adsorption.
  • 0.1–1 mM EDTA to limit metal-catalyzed photobleaching.
  • 0.1–0.5% carrier protein (unlabeled BSA) when handling very low concentrations to mitigate sticking (note that added unlabeled BSA will dilute fluorescence per mass).

• Blocking and wash buffers (literature):

  • 1–5% BSA in PBS/TBS for blocking. If fluorescent monitoring of blocking is desired, use a low concentration of BSA–FITC or spike-in a defined fraction into the blocking solution to visualize coverage.

• pH and fluorescence:

  • Maintain pH ≥7.2 for maximum fluorescein emission; avoid acidic buffers for imaging to prevent quenching. For fixed samples, mount in neutral to slightly basic antifade media.

Green Alternatives

While BSA–FITC itself is an aqueous, protein-based reagent, greener practices center on minimizing hazardous solvents, reducing waste from repeated imaging, and choosing more photostable dyes when appropriate.

• Reduce solvent use:

  • Perform all dilutions in water-based buffers (PBS/HEPES). Avoid organic cosolvents that denature proteins and create hazardous waste streams.

• Improve photostability to reduce repeats (literature):

  • Consider switching to more photostable green-emitting dyes (e.g., Alexa Fluor 488, Atto 488) when long imaging sessions are required. Fewer repeats mean less consumable and energy use.

• Antifade and oxygen control (literature):

  • Use commercial antifade mounting media or oxygen scavenging systems (e.g., glucose oxidase/catalase) to prolong signal, minimizing rework.

Small comparison (literature/general):

• FITC (this item):

  • Pros: Economical, widely compatible, standard filter sets.
  • Cons: pH-sensitive brightness, moderate photostability.

• Alexa Fluor 488–BSA (alternative):

  • Pros: Higher photostability, brighter, less pH sensitivity.
  • Cons: Typically higher cost; may require procurement of a different conjugate.

• Operational green tips:

  • Aliquot to avoid freeze–thaw waste.
  • Use reusable amber glassware/vials for storage to cut single-use plastics.
  • Optimize exposure and binning to lower laser power and extend sample lifetime.

Pharmaceutical Uses

This product is designated For research use only and is not intended for human or veterinary use, clinical diagnostics, or therapeutic applications.

General, non-clinical notes (literature/context):

• BSA is widely used in pharmaceutical laboratories as a process aid, protein standard, or stabilizer during method development and analytical characterization. When fluorescently labeled (e.g., with FITC), it can serve as a tracer for device/surface studies, filtration validation, and process visualization in development environments.
• No pharmacopeial status, excipient grade, sterility, bioburden, or endotoxin specifications are provided for this item. Any use in regulated workflows would require independent qualification.

If your application requires defined excipient specifications (e.g., USP/NF, low endotoxin), please consult products explicitly labeled for those purposes or request documentation confirming suitability. This item is not specified for such uses.

Physical Properties

Item-specific physicochemical constants are not specified; refer to CoA/Spec Sheet. The following are general/literature properties to guide handling and detection of BSA–FITC conjugates:

• Appearance: Not specified for this item; refer to CoA/Spec Sheet. (Commonly supplied as aqueous solution or lyophilized solid with a faint yellow-green hue, literature.)
• Solubility (literature): Highly soluble in aqueous buffers (e.g., PBS, TBS). Avoid high concentrations of strong denaturants unless intended (e.g., >6 M urea or >4 M guanidinium HCl can unfold BSA and alter fluorescence environment).
• pH dependence (literature): Fluorescein fluorescence increases above pH ~6 with an apparent pKa ~6.3–6.5; optimal brightness typically at pH 7.4–8.5.
• Spectral properties (fluorophore, literature):
  • Excitation maximum ~494–495 nm
  • Emission maximum ~517–520 nm
  • Extinction coefficient (FITC chromophore) ~70,000–75,000 M⁻¹ cm⁻¹ at ~495 nm when fully deprotonated; note that on-protein values are environment- and DOL-dependent.
• Aggregation (literature): Over-labeling or high concentration can promote intermolecular interactions and self-quenching; maintain moderate labeling densities and suitable ionic strength to minimize quench.
• Density, MP/BP, refractive index, logP: Not applicable/meaningful for macromolecular conjugates; not specified for this item.

Always verify exact concentration, DOL, and buffer composition on the item’s CoA/Spec Sheet before quantitative work.

Quality and Grades

• Item-specific grade: Suitable for Immunofluorescence (IF), BioReagent.

What this means in practice:

• Suitable for IF: Indicates the conjugate quality and fluorescence performance are appropriate for fluorescence microscopy workflows, including sample preparation under subdued light and imaging in standard FITC/GFP filter sets. This does not imply a specific degree of labeling (DOL) or concentration; consult the CoA/Spec Sheet for item-specific parameters if provided.
• BioReagent: Indicates suitability for general laboratory research use. It does not confer clinical/diagnostic status and does not imply sterility or endotoxin specification unless stated. For cell-based work, consider sterile filtration if compatible and required by your application.

Stabilizers, preservatives, and buffer: Not specified for this item; refer to CoA/Spec Sheet. Stabilizers (e.g., sugars or proteins) and preservatives (e.g., sodium azide, ProClin) are sometimes included in protein conjugates; their presence can impact downstream assays (e.g., azide incompatibility with peroxidases, literature). Verify before use.

Batch-to-batch consistency: For quantitative fluorescence applications, confirm concentration (mg/mL) and DOL, and standardize imaging settings across lots. Retain lot-specific CoA for audit trails.

Compliance: For research use only; not for human or veterinary use, in vitro diagnostics, or clinical applications.

Reaction and Applications

BSA–FITC is not used as a synthetic reagent; its value lies in fluorescence-based applications. The following are common research uses (literature/general):

• Immunofluorescence (IF):

  • As a fluorescent tracer to assess sample preparation, imaging alignment, and channel calibration with FITC/GFP filter sets.
  • As a surrogate antigen-free probe to evaluate background and nonspecific binding in tissue sections when developing IF workflows.

• Cellular uptake and permeability assays:

  • Monitor endocytosis or barrier integrity by tracking FITC–BSA internalization or trans-epithelial/vascular passage in model systems (e.g., transwell inserts, microfluidics).

• Surface blocking and tracing:

  • BSA is frequently used for blocking; the FITC label allows visualization of surface coverage, adsorption, or desorption kinetics on materials.

• Microscopy calibration and teaching:

  • Establish exposure times, laser powers, and detector gains in the green channel. Create in-house intensity standards via serial dilutions.

Practical tips (literature):

• Prevent photobleaching: Work under low light, use antifade reagents, and minimize dwell time under illumination.
• Control DOL effects: Over-labeling can reduce fluorescence due to self-quenching; if DOL is provided on the CoA, aim for mid-range values for balanced brightness and solubility.
• Adsorption: Precondition plasticware with buffer containing carrier protein or detergent to reduce loss of analyte at low concentrations.

Reaction Conditions

No chemical reaction conditions are required to use this product; it is a ready-to-use fluorescent protein conjugate. The following handling and measurement conditions (general/literature) help maximize performance:

• Working concentration: Typical 1–50 µg/mL for imaging/tracing; optimize by application and instrumentation. Exact stock concentration for this item is not specified; refer to CoA/Spec Sheet.
• pH/Buffer: Use pH 7.2–8.0 (PBS/TBS/HEPES) for maximal fluorescein brightness. Avoid acidic conditions during imaging.
• Temperature: Keep on ice during setup; perform incubations at room temperature unless biological models dictate otherwise. Avoid >37 °C for extended periods to limit denaturation.
• Light: Protect from ambient/UV light. Minimize exposure on the microscope (lower laser power, shorter exposure, higher detector gain within linear range).
• Additives: Optional antifade reagents and 0.01–0.05% Tween-20 can reduce photobleaching and surface adsorption, respectively.
• Spectroscopy (literature): Record absorbance at ~280 nm (protein) and ~495 nm (FITC) to estimate DOL if extinction coefficients are known. For this item, DOL is not specified; any calculation requires item-specific constants.

These guidelines are general. Adjust as needed for your cell model, matrix, and detection hardware.

Safety and Handling

Authoritative safety data are provided in the SDS. The following are general laboratory precautions for protein–fluorophore conjugates:

• GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.
• Primary hazards (general): Low inherent chemical hazard under normal lab use. Handle as a biological reagent; avoid inhalation of powders/aerosols, ingestion, and skin/eye contact. Some users may have allergies to animal proteins.
• Light sensitivity: FITC is light-sensitive. Work under subdued light; protect containers and samples with foil or amber vials to minimize photobleaching.
• Thermal sensitivity: Avoid repeated freeze–thaw cycles; keep cold during handling (ice bath) to preserve protein integrity.
• Incompatibilities (general):
  • Strong oxidants, strong acids/bases that denature proteins.
  • Copper ions and transition metals can catalyze dye photobleaching; include chelators (e.g., 0.1–1 mM EDTA) if compatible with your assay (literature guidance).
  • Amines at high concentration may quench fluorescein or compete in conjugation workflows (if further labeling is attempted).
• PPE: Lab coat, gloves, safety glasses. Use biosafety cabinet if generating aerosols.
• First aid (general): Rinse eyes/skin with water on contact; seek medical attention as needed. If inhaled, move to fresh air. If ingested, rinse mouth and seek advice.
• Waste: Dispose according to institutional and local regulations for nonhazardous laboratory biochemicals; avoid release to drains when containing preservatives or dyes.

Solvent Selection

As a protein conjugate, BSA–FITC is formulated for aqueous use rather than organic solvents.

• Primary medium: Aqueous buffers (literature):

  • Phosphate-buffered saline (PBS), Tris-buffered saline (TBS), or HEPES buffer, pH 7.2–8.0.
  • Ionic strength (e.g., 150 mM NaCl) promotes protein stability and reduces nonspecific adsorption.
  • Include 0.01–0.1% carrier proteins or detergents (e.g., 0.01–0.05% Tween-20) to minimize surface losses if compatible with your assay.

• pH considerations (literature): Fluorescein brightness increases above pH ~6.4; imaging at pH 7.4–8.0 maximizes signal. Avoid pH <6 during imaging to prevent quenching.

• Organic cosolvents: Minimize. Small percentages (≤5–10% v/v) of glycerol or ethylene glycol can stabilize proteins for storage; high levels of alcohols/acetone/acetonitrile can denature BSA and should be avoided.

• Chelators and salts (literature): 0.1–1 mM EDTA may reduce metal-catalyzed photobleaching. Maintain moderate ionic strength to suppress aggregation.

• Comparison (general):

  • PBS (pH 7.4): Widely compatible, maintains fluorescein brightness; phosphate may interact with certain metal-dependent systems.
  • Tris (pH 7.4–8.0): Good buffering in the fluorescein-optimal range; primary amine can interfere only if additional NHS/isothiocyanate labeling steps are planned.
  • HEPES: Minimal amine interference; excellent for live-cell environments and imaging.

Storage and Reconstitution

• Storage conditions (item-specific):

  • Store at −20 °C; protect from light.
  • Shipped in: Ice chest + ice pads.

• Appearance, buffer composition, concentration: Not specified for this item; refer to CoA/Spec Sheet.

• Reconstitution (if lyophilized; general guidance):

  • Reconstitute in sterile, neutral pH buffer (e.g., PBS, pH 7.4) to the desired concentration. Gently invert to dissolve; do not vortex vigorously to avoid foaming/denaturation.
  • Optional: Add 10–50% glycerol for subzero storage to reduce freeze–thaw stress (confirm compatibility with your assay).

• Aliquoting and stability (general):

  • Aliquot into light-protected microtubes to avoid repeated freeze–thaw cycles.
  • Short-term (days to weeks): 2–8 °C protected from light may be acceptable for working stocks; verify performance empirically.
  • Long-term: −20 °C as specified. For very long-term storage, −80 °C can further preserve activity if compatible with buffer components.

• Handling:

  • Thaw on ice, mix gently, and keep samples protected from light at all times.
  • Avoid microbial contamination; if sterility is required, sterile-filter through low-protein-binding 0.22 µm membranes.

Always consult the lot-specific CoA/Spec Sheet for concentration, DOL, buffer, and any stabilizers/preservatives present.

Structure and Identity

BSA, FITC conjugate is a protein–fluorophore conjugate consisting of bovine serum albumin (BSA) covalently labeled with fluorescein isothiocyanate (FITC).

• Item-specific identifiers:

  • SKU: B1509129
  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet. (Note: unlabeled BSA is ~66 kDa, literature.)
  • InChIKey: Not applicable to proteins/conjugates.
  • SMILES: Not applicable to proteins/conjugates.

• Structural features (general/literature):

  • BSA is a single-chain, ~583–585 amino-acid serum albumin with 17 intramolecular disulfides (literature), presenting a heart-shaped, predominantly α-helical protein.
  • FITC (isothiocyanate of fluorescein) reacts with accessible lysine ε-amines to form stable thiourea linkages (literature). Degree of labeling (DOL) is typically in the range of ~2–10 dyes/protein for many commercial preparations (literature; DOL for this item is not specified).
  • Fluorescein chromophore: xanthene core with phenolic groups; exhibits pH-dependent ionization affecting brightness (literature).

• 2D description in words:

  • A large globular protein (BSA) bearing multiple pendant fluorescein dye moieties attached via –NH–C(=S)–NH– linkages at lysine residues. The protein scaffold provides solubility and biochemical compatibility; the fluorescein tags confer green fluorescence (Ex/Em max ~494/518 nm, literature).

Synthetic Utility

BSA–FITC is not a building block or reagent for chemical synthesis; it is a finished biomolecular probe. Consequently, standard synthetic chemistry use-cases (e.g., as a nucleophile/electrophile, catalyst, or solvent) do not apply.

Relevant, adjacent utility (literature/general):

• Assay development tool: Serves as a fluorescent macromolecular standard to validate chromatographic (e.g., SEC with fluorescence detection), electrophoretic, and imaging systems.
• Conjugation benchmarking: Useful as a positive control when optimizing labeling, purification, and desalting workflows, since signal recovery can be quantified by absorbance/fluorescence.
• Surface chemistry studies: Enables visualization of protein adsorption, antifouling coatings, and desorption kinetics on materials used in microfluidics or biosensors.

For users seeking to perform the conjugation themselves (outside this product’s scope), note that fluorescein isothiocyanate reacts with primary amines at pH ~8–9 to form thiourea bonds (literature). However, this product is already conjugated and ready-to-use for fluorescence workflows.

Target Specificity

Not applicable. BSA–FITC does not have antigen specificity and is not an antibody or affinity reagent. It functions as a fluorescent macromolecular tracer and general-purpose probe.

• Antigen/epitope: Not applicable.
• Species reactivity: Not applicable.
• Clone/isotype: Not applicable.

For target-specific labeling, use antibodies or ligands conjugated to FITC/Alexa-class dyes that recognize your protein or pathway of interest.

Domande frequenti

What does Suitable for Immunofluorescence(IF) mean?

Suitable for Immunofluorescence(IF) indicates the product has been validated for use in immunoassays such as ELISA, IF, IHC and flow cytometry. Validation may include positive/negative control samples, signal-to-noise testing, and protocol-specific QC. Lot-specific test data is published on the Certificate of Analysis where available.

What does BioReagent mean?

BioReagent indicates that the product has been processed and tested for biological and biochemical applications. Specifications may include endotoxin limits, microbial controls, sterility, low DNase/RNase/protease activity, and verified biological activity where relevant.

How should this product be stored?

Store at ?20 °C, protected from light. The material is light-sensitive — keep it in its original opaque or amber container.

How is this product shipped?

This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.