8 Arm PEG Biotin - MW 40000 Da

Cat. No.: A163133

GRADE & PURITY MW 40000 Da

Storage

Room temperature

Shipped In

Normal

Visão geral

8 arm PEG derivatives have multiple reactive groups that can be used to modify proteins, peptides and other materials via their functional groups. PEGylation can increase solubility and stability and reduce immunogenicity of peptides and proteins. It can also suppress the non-specific binding of charged molecules to the modified surfaces. .

Specifications

Especificações e pureza

MW 40000 Da

Condições de armazenamento de armazenamento

Room temperature

Enviado em

Normal

Propriedades químicas e físicas

• Solubilidade: Off-white/white solid or viscous liquid depends on molecule weight;Soluble in regular aqeous solution as well as most organic solvents

Application Protocols

No vendor-tested application protocols are provided for this SKU. The following example workflows are literature-based and should be optimized by the user.

A. Coating streptavidin surfaces with 8-arm PEG–biotin (surface passivation and handle presentation)

• Prepare 0.1–0.5 mg/mL polymer in PBS (pH 7.4), optionally 0.01% Tween 20.
• Rinse streptavidin-coated plate or chip with PBS. Add polymer solution to fully cover surface.
• Incubate 30–60 min at room temperature with gentle agitation.
• Wash 3× with PBS. Proceed to add biotinylated capture ligands at desired concentrations.

B. Formation of streptavidin-crosslinked PEG hydrogels (qualitative)

• Prepare polymer solution (e.g., 1–5% w/v in PBS). Separately, prepare streptavidin solution.
• Mix solutions to target near-stoichiometric ratio of biotin end-groups to streptavidin binding sites (4 per tetramer). Vortex gently; avoid bubbles.
• Allow to stand at room temperature; monitor gelation (minutes to hours depending on Mn and concentration). Adjust modulus by polymer concentration and stoichiometry.

C. Affinity capture enhancement

• Add polymer (1–50 µg/mL) to streptavidin-coated magnetic beads to increase PEG passivation and provide multivalent binding sites. Wash, then introduce biotinylated target. Optimize to balance passivation with capacity.

Note: Validate concentrations and times for your specific assay and the item’s functionalization level (consult CoA).

Biological Roles

This section addresses biological context of the functional groups; no therapeutic claims are made.

Literature context (non-item-specific):

• Biotin (vitamin B7) is a natural cofactor covalently attached to carboxylases (e.g., pyruvate carboxylase, acetyl-CoA carboxylase) via a lysine residue (biocytin). Its strong noncovalent binding to avidin/streptavidin underpins numerous bioanalytical and biomaterials applications.
• PEG (polyethylene glycol) is a hydrophilic, nonionic polymer known for protein-repellent properties, increased solubility, and reduced nonspecific adsorption. PEGylation of surfaces and macromolecules often improves colloidal stability and decreases biofouling.
• 8-arm PEG–biotin exploits these features to present multiple biotin ligands in a hydrated, protein-resistant corona, enabling high-avidity interactions with streptavidin-family proteins. This multivalency can drive assembly of supramolecular networks, targeted localization on streptavidin-bearing interfaces, and signal amplification in assays.
• Binding characteristics: biotin–streptavidin Kd ~10^−14–10^−15 M (literature), effectively irreversible under typical assay conditions, yet dissociable under harsh conditions (e.g., boiling SDS, high guanidine). NeutrAvidin provides lower nonspecific binding in many applications.

Note: Exact degree of functionalization, linker chemistry, and polymer Mn govern hydrodynamic size, diffusion, and binding stoichiometry. Consult the item’s CoA/Spec for these determinants if critical to experimental design.

Buffer Applications

Not a buffering reagent. 8 Arm PEG Biotin does not establish or control pH and is not used to prepare standard biological buffers.

Practical guidance (literature):

• Use physiologically compatible buffers (e.g., PBS, TBS, HEPES) at pH 7.2–7.6 for biotin–streptavidin assembly to maintain protein integrity and minimize nonspecific interactions.
• Include 0.01–0.1% nonionic surfactant (e.g., Tween 20) when working on surfaces to reduce nonspecific adsorption (validate for your assay).
• Maintain moderate ionic strength (≥150 mM NaCl) to screen electrostatics; avoid strong bases/acids that could hydrolyze linkers in some PEG–biotin constructs (general note, not item-specific).

Green Alternatives

Context: 8 Arm PEG Biotin is a functional macromolecule, not a commodity solvent or reagent with direct “drop-in” green substitutes. Greener practice focuses on solvent choice, energy input, and waste minimization during its use (literature guidance).

Greener handling strategies:

• Prefer aqueous buffers (PBS, HEPES) over organic solvents where possible. Prepare concentrated aqueous stocks to avoid DMSO/DMF.
• Room-temperature assembly: Biotin–streptavidin interactions proceed efficiently at ambient temperature; avoid unnecessary heating/cooling.
• Minimize excess: Calculate stoichiometry based on functionalization per arm to limit unbound polymer and downstream purification burden.
• Reusable supports: Use streptavidin-coated solid phases designed for regeneration (where compatible) to reduce consumable waste.

Comparative considerations (literature, non-item-specific):

• Monovalent small-molecule biotin vs PEG–biotin polymers:
  • Environmental: Polymers may increase persistence; however, reduced amounts may be needed due to multivalency.
  • Performance: Multivalency can lower required concentration but may complicate disposal; aqueous use conditions favor greener profiles.

Summary table (literature):

• Parameter | Greener choice/impact
• Solvent | Water-based buffers preferred over DMSO/DMF
• Temperature | Ambient conditions adequate; avoid heating
• Quantity | Use stoichiometric calculations to minimize excess
• Purification | Choose magnetic or reusable supports to cut solvent use

Always follow institutional green-chemistry policies for polymer disposal and solvent reduction.

Pharmaceutical Uses

For research use only. No clinical or therapeutic use is claimed or supported for this SKU.

Literature/formulation context (non-item-specific):

• PEG–biotin polymers are employed in R&D settings for affinity-based separations, diagnostic assay development, and biomaterials prototyping. The multivalent biotin display enables robust, noncovalent assembly to streptavidin-labeled components used in assay and device manufacture.
• Potential roles in development workflows include:
  • Surface passivation of diagnostic components (chips, microtiter wells) while providing biotin handles for modular assembly.
  • Construction of reversible, biotin–streptavidin crosslinked hydrogels for screening and mechanobiology tools.
  • Affinity capture/release systems in upstream/downstream bioprocess research.
• Regulatory/compendial status: Not specified for this item; refer to CoA/Spec Sheet. In general, specialized PEG–biotin macromolecules are not monographed in pharmacopeias and are used as research-grade materials unless otherwise stated by the supplier.

Note: Any use in manufacturing or as an excipient would require qualification to relevant standards (bioburden, endotoxin, residuals) not provided here. Confirm specifications and regulatory suitability before considering such applications.

Physical Properties

Item-specific physical data (exact values): Not specified for this item; refer to CoA/Spec Sheet.

General/literature characteristics for 8-arm PEG–biotin (non-item-specific):

• Physical state: depending on arm length/Mn, materials range from free-flowing white solids/waxes to viscous syrups (literature).
• Solubility: highly soluble in water and many polar protic/apyric solvents (e.g., PBS, saline, methanol, ethanol, DMSO). Solubility in nonpolar solvents is poor due to PEG polarity (literature).
• Hygroscopicity: PEGs are mildly hygroscopic; water uptake can alter mass concentration and effective biotin density. Work in controlled humidity and record water content if critical (literature best practice).
• pKa/logP: not applicable for the polymer backbone; terminal biotin is neutral at physiological pH; overall macromolecule behaves as a nonionic hydrophile (literature).
• Viscosity: solutions can be viscous at high concentration; diffusion and binding kinetics may be slower than with monovalent biotin (literature).
• Thermal behavior: PEG glass transition typically around −60 to −20 C depending on Mn; softening/melting broad and Mn-dependent; avoid prolonged heating above ~60–80 C to prevent degradation (literature guidance).

Analytical notes:

• Typical characterization uses 1H NMR (end-group analysis), MALDI-TOF/ESI (average Mn), SEC/GPC (Mw, PDI), and HPLC/UV for biotin content (literature). Exact specs for this item are not provided here.

Quality and Grades

Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.

How to interpret quality for 8-arm PEG–biotin (general guidance):

• Purity of macromolecules is multidimensional. Key metrics include:
  • Average molecular weight per arm and per molecule (Mn) and dispersity (Đ or PDI). Lower dispersity supports consistent binding stoichiometry.
  • End-group conversion/functionalization efficiency (% biotinylation per arm). Near-quantitative substitution is desirable for predictable multivalency.
  • Residual small-molecule impurities (unreacted biotin/linkers), solvents, catalysts—important for bioassays.
  • Water/volatile content and ash/metals (if relevant for downstream applications). For this SKU, these are Not specified for this item; refer to CoA/Spec Sheet.
• Stabilizers: Generally not required for PEG–biotin; if present (e.g., antioxidant), it should be disclosed on the CoA.

What to expect in documentation:

• NMR spectra showing PEG backbone and biotin resonances; integration for end-group analysis.
• SEC/GPC traces with calibration details.
• Mass spectrometry (MALDI/ESI) for average Mn where feasible.
• HPLC/UV data for free biotin removal.

Fit-for-purpose suggestions:

• For quantitative avidin/streptavidin crosslinking or surface assembly, prioritize lots with high end-group conversion and narrow Đ.
• For routine capture/immobilization, slightly broader Đ may be acceptable.

Reaction and Applications

Manufacturer application text: Not provided beyond the product name. The following expands on typical uses of 8-arm PEG–biotin in research (literature; non-item-specific):

• Ultra-high-affinity capture via biotin–(strept)avidin: The biotin moieties bind streptavidin/avidin/NeutrAvidin with femtomolar affinity, enabling robust, noncovalent assembly. The 8-arm scaffold provides multivalent presentation for enhanced avidity and crosslinking.
• Hydrogel and network formation: In the presence of tetravalent streptavidin, 8-arm PEG–biotin can form reversible physical gels/crosslinked networks. Tunable mechanics arise from concentration, arm length, and stoichiometry (literature).
• Surface engineering: Coating or patterning of streptavidin-functionalized surfaces (chips, beads, nanoparticles) to create PEGylated, protein-resistant layers while providing biotin handles for second-stage assembly.
• Signal amplification: Multivalent display of biotin enables recruitment of multiple streptavidin–enzyme/fluorophore conjugates for enhanced assay sensitivity (ELISA, blotting, biosensors).
• Affinity purification: Bridges between biotinylated targets and streptavidin matrices; can act as a multivalent spacer to reduce steric hindrance and improve capture.

Practical tips:

• Work near neutral pH (6.8–8.0). High ionic strength (≥150 mM NaCl) reduces nonspecific interactions.
• Optimize stoichiometry to avoid precipitation/over-crosslinking in solution-phase work. Titrate polymer to streptavidin equivalents based on end-group conversion.
• Gentle mixing preserves protein activity; avoid organic content >10% when proteins are present unless validated.

Reaction Conditions

There are no covalent “reactions” intrinsic to use; applications typically exploit noncovalent biotin–streptavidin binding. The following are general, literature-based conditions for common workflows (non-item-specific):

• Streptavidin binding/assembly:
  • Buffer: PBS or TBS, pH 7.2–7.6; 1–2 mM EDTA optional to chelate adventitious metals.
  • Ionic strength: ~150 mM NaCl minimizes nonspecific interactions.
  • Temperature: 20–25 C; low temperatures (4 C) slow kinetics but can reduce proteolysis.
  • Concentrations: polymer 0.01–1 mg/mL typical; adjust based on arm Mn and desired stoichiometry. Equivalents of biotin to streptavidin binding sites (4/site) govern crosslinking density.
  • Time: 15–60 min for surface binding; longer for bulk gelation or diffusion-limited systems.
• Hydrogel formation with streptavidin:
  • Mix stoichiometric equivalents of biotin end-groups to streptavidin tetramer binding sites; monitor viscoelasticity (rheometry) to tune modulus. Excess polymer can lead to phase separation.
• Surface functionalization:
  • Pre-rinse streptavidin-coated substrates with buffer containing 0.01% Tween 20. Incubate with polymer solution, wash to remove unbound material, then add secondary biotinylated components.

Notes:

• Avoid extremes of pH (>9 or <5) that can weaken protein activity or hydrolyze linkers (if ester-based). High concentrations of free biotin will competitively displace polymer.

Safety and Handling

GHS/SDS information for this SKU:

• Signal word: Not specified for this item; refer to CoA/Spec Sheet and SDS.
• Hazard statements, pictograms, GHS classification: Not specified for this item; refer to SDS.

General handling guidance (literature/best practice):

• PEG-based materials and biotinylated PEGs are generally regarded as low hazard for laboratory handling; nevertheless, avoid inhalation of dust/aerosols and skin/eye contact. Use standard lab PPE: lab coat, gloves (nitrile), safety glasses.
• Work in a clean, dry environment. PEGs can absorb moisture and adventitious salts; store desiccated when possible. Close containers promptly to prevent hydration and contamination.
• Incompatibilities: strong oxidizers may attack PEG chains; strong acids/bases and elevated temperatures can accelerate hydrolysis of linkers (if ester/urethane present in this specific material). Keep away from reactive acylation/oxidation reagents unless intended.
• First aid (overview; defer to SDS): rinse eyes/skin with water upon contact; if inhaled, move to fresh air; if ingested, rinse mouth and seek medical advice.
• Waste: dispose according to institutional and local regulations for nonhazardous organic polymers.

Special notes:

• Dust formation can be minimized by handling as solutions. If preparing concentrated solutions, consider sterile filtration (0.22 µm) for biological assays to reduce bioburden (lab practice, not a sterile specification).

Solvent Selection

Applicability: As a hydrophilic macromolecule, 8 Arm PEG Biotin is typically handled in aqueous buffers or polar organic solvents.

General/literature solvent behavior (non-item-specific):

• Preferred solvents: water, PBS, HEPES buffer, Tris buffer (pH ~7–8), and polar organics such as DMSO, DMF, methanol, ethanol.
• Miscibility: PEG derivatives are generally miscible with water and many lower alcohols; partial miscibility with acetone and acetonitrile can occur; immiscible or poorly soluble in nonpolar solvents (hexanes, toluene) (literature).
• Practical choices:
  • Aqueous binding/assembly with streptavidin/avidin is best performed in PBS or TBS with moderate ionic strength (e.g., 150 mM NaCl) to minimize nonspecific adsorption.
  • For stock solutions of high-Mn materials, DMSO can help achieve higher concentrations; dilute into buffer immediately before use to avoid DMSO effects on proteins.
• Filtration: 0.22–0.45 µm syringe filtration helps remove particulates/aggregates before sensitive assays.

Comparison (literature):

• Monofunctional biotin: soluble in DMF/DMSO; less water-soluble than PEG–biotin conjugates.
• 4-arm vs 8-arm PEG–biotin: similar solvent preferences; higher arm number increases hydrodynamic radius and solution viscosity, sometimes requiring slower addition and longer mixing for homogeneity.

Notes: Check the CoA for any solvent limitations or stability notes specific to this SKU (e.g., ester-linked biotin may hydrolyze faster in high-pH buffers).

Storage and Reconstitution

Item-specific storage/shipping:

• Storage conditions: Room temperature (per Product Data). Store tightly closed in a dry place, protected from light if sensitive linkers are suspected.
• Shipped in: Normal (per Product Data).

General reconstitution guidance (literature; non-item-specific):

• Solvents: Water, PBS, or other neutral buffers are preferred. For highly concentrated stocks, DMSO or DMF can be used, followed by dilution into aqueous buffer immediately before use.
• Concentration: Prepare stocks at 1–100 mg/mL depending on solubility and application. Record exact concentration gravimetrically, accounting for moisture uptake where possible.
• Filtration: Sterile-filter (0.22 µm) for cell-adjacent assays. This product is not supplied as sterile unless explicitly stated on CoA.
• Handling: Avoid repeated freeze–thaw of solutions; aliquot and store at 4 C for short term (days to weeks) or at −20 C for longer term if compatible with your application. Solid form prefers desiccated storage.
• Stability: Avoid prolonged exposure to strong light, elevated temperature, or extreme pH that may degrade linkers or PEG chains. Do not store solutions in reactive metal containers.

Always consult the product’s CoA/Spec Sheet for any item-specific stability data, recommended solvents, and shelf-life information.

Structure and Identity

Item-specific identifiers (CAS, InChIKey, SMILES, formula, exact molecular weight): Not specified for this item; refer to CoA/Spec Sheet.

General/literature description (non-item-specific):

• 8 Arm PEG Biotin typically denotes a star-shaped poly(ethylene glycol) (PEG) macromolecule with an 8-functional core from which eight PEG chains emanate, each terminated with a biotin moiety via a linker (often an amide/urea/ether-type spacer). The core is commonly a multifunctional polyol scaffold (e.g., pentaerythritol or dendritic variants), but exact chemistry varies by manufacturer (literature).
• Structural features: eight PEG chains (–[O–CH2–CH2]n–) providing hydrophilicity and water solubility; terminal biotin functionalities capable of ultra-high affinity binding to avidin/streptavidin/NeutrAvidin proteins (literature). No stereocenters in PEG backbone; biotin contains bicyclic ureido-tetrahydrothiophene structure.
• 2D depiction (verbal): central hub (core) connected to eight flexible ethylene oxide chains that radiate outward; each chain ends with a biotin group. The biotin ring system features a fused imidazolidone and thiophane ring with a valeric acid-derived linker (literature).

Notes for users:

• Degree of polymerization (DP) per arm, exact linker type, and average Mn/Mw/PDI critically define performance; consult the CoA/Spec Sheet for this specific SKU.

Synthetic Utility

Although supplied as a finished macromolecular reagent, 8 Arm PEG Biotin can serve as a versatile scaffold in synthesis and assembly (literature; non-item-specific):

• Multivalent ligand presentation: Eight terminal biotin groups enable programmed, noncovalent assembly with streptavidin-family proteins to build higher-order architectures (networks, lattices, hydrogels), useful for templating and display technologies.
• Modular surface chemistry: On streptavidin-coated substrates, the polymer provides a PEG cushion with accessible binding sites for further biotinylated components, enabling sequential, orthogonal assembly.
• Spacer/solubilizer: The PEG arms act as hydrophilic spacers, improving aqueous solubility of bound cargos and reducing steric hindrance in affinity capture.
• Retrosynthetic perspective: Star-PEG cores bearing protected handles can be diversified prior to biotin installation. If the core retains functional groups (not specified for this item), users may further derivatize for bespoke architectures.

Analytical and process notes:

• End-group verification by 1H NMR and HPLC quantitation of free biotin is critical to ensure the intended valency.
• For covalent routes, common linkages to biotin include amide coupling (activated esters), click reactions (azide–alkyne), and thiol–maleimide, but the exact chemistry of this SKU is not specified; consult CoA/Spec.

Target Specificity

Item-specific biological target data (antigen/clone/isotype/species): Not applicable; this product is not an antibody or protein reagent. No item-specific target data are provided.

Literature-based interaction specificity (non-item-specific):

• The terminal biotin groups exhibit ultra-high specificity and affinity for avidin, streptavidin, and NeutrAvidin, forming a tight noncovalent complex (Kd ~10^−14–10^−15 M). Binding is highly selective for the biotin-binding pocket; cross-reactivity with unrelated proteins is minimal under standard buffer conditions.
• Stoichiometry: Each streptavidin tetramer has four biotin-binding sites; multivalent polymers like 8-arm PEG–biotin can engage multiple sites on one or more tetramers, leading to crosslinking and network formation depending on concentration and geometry (literature).

Caveats:

• Presence of free biotin or biotinylated contaminants competes for binding sites and reduces effective coupling.
• Harsh denaturants, SDS at high temperature, or very low pH can disrupt complexes, enabling deliberate dissociation when required.