8 bras PEG Maléimide - MW 10000 Da

Cat. No.: A163136

GRADE & PURITY MW 10000 Da

Synonyms

maléimide PEG10K à 8 bras

Storage

Protégé de la lumière,Stocker à -20°C,Chargé à l'argon

Shipped In

Glacière + blocs de glace

Vue d’ensemble

les dérivés du PEG 8 arm possèdent de nombreux groupes réactifs qui peuvent être utilisés pour modifier les protéines, les peptides et d'autres matériaux par l'intermédiaire de leurs groupes fonctionnels. La PEGylation peut augmenter la solubilité et la stabilité et réduire l'immunogénicité des peptides et des protéines. Elle peut également supprimer la liaison non spécifique de molécules chargées sur les surfaces modifiées. .
Les applications peuvent comprendre : la bioconjugaison, l'administration de médicaments, les hydrogels PEG, les réticulateurs et la fonctionnalisation des surfaces

Specifications

Synonymes

maléimide PEG10K à 8 bras

Spécifications et pureté

MW 10000 Da

Conditions de stockage de stockage

Protégé de la lumière,Stocker à -20°C,Chargé à l'argon

Expédié en

Glacière + blocs de glace

Propriétés chimiques et physiques

• Solubilité: Off-white/white solid or viscous liquid depends on molecule weight;Soluble in regular aqeous solution as well as most organic solvents
• Sensibilité: light and moisture sensitive

Application Protocols

Tested application protocols, recommended dilutions, and positive controls are not specified for this item; refer to CoA/Spec Sheet and SDS.

Note: General, literature-based procedural guidance for thiol–maleimide conjugation and hydrogel formation is provided in the sections Reaction & Applications, Buffer Applications, and Reaction Conditions.

Biological Roles

This product is a synthetic polymeric reagent rather than a biological macromolecule. The following describes general, literature-based interactions relevant to laboratory research (not clinical use).

• PEG as a biomaterials component (literature/general):
  • PEG is protein-resistant: Hydrated PEG chains form steric and enthalpic barriers that reduce nonspecific protein adsorption and cell adhesion on surfaces.
  • Inert spacer/linker: PEG’s flexibility and hydrophilicity make it a widely used linker to space functional moieties and to modulate hydrodynamic size in conjugates.
• Maleimide–thiol bioconjugation relevance (literature):
  • Enables site-specific cysteine modification on proteins and peptides, facilitating controlled attachment of probes, handles, or crosslinkers.
  • In multivalent formats (8-arm), can create networked environments (hydrogels) that influence cell behavior in vitro by providing tunable mechanical and biochemical cues (for research use only).
• Stability considerations in biological media (literature):
  • Maleimide–thiol adducts are thioethers; in certain cases, succinimide–thioether can undergo retro-Michael/exchange at high pH or with excess thiols. Ring-opening (hydrolysis) to a maleamic acid thioether improves long-term stability.
• No endogenous biological role: The polymer does not participate in metabolic pathways; it is a tool for modifying biomolecules and materials in controlled research settings.

Buffer Applications

This product is not a pH buffer. However, successful use relies on appropriate buffer systems for thiol–maleimide coupling (literature/general guidance).

• Recommended buffer systems (no amines, no thiols):
  • Phosphate (10–50 mM), pH 6.5–7.2, 0–150 mM NaCl, 1–5 mM EDTA.
  • HEPES (10–50 mM), pH 6.8–7.4, 0–150 mM NaCl, 1–5 mM EDTA.
  • Avoid Tris, glycine, or other primary amine buffers that can compete/react; avoid reducing agents like DTT, BME, or glutathione until the intended reaction.
• Preparation tips:
  • Degas buffers (N2 or Ar sparge) to limit thiol oxidation; filter-sterilize if used with proteins/cells.
  • Adjust ionic strength to preserve protein stability if performing bioconjugation; include EDTA to chelate trace metals.
• Working concentrations and times (literature):
  • Stock polymer solutions: 10–200 mg/mL in buffer or anhydrous DMSO; dilute into buffer immediately before use.
  • Reaction times: 10 min to 2 h at 20–25 °C; slower at 4 °C.

Note: The above are general recommendations and not item-specific specifications. Verify compatibility with your biomolecule and intended application.

Green Alternatives

Greener practice focuses on solvent choice, reaction conditions, and reagent selection rather than changing the core functionality, since maleimide–thiol click is already high-yielding and atom-economical.

• Greener solvent/use conditions (literature/general):
  • Prefer aqueous buffers (phosphate or HEPES, pH 6.5–7.2) over DMF/DMSO when biomolecule compatibility allows. Run at ambient temperature and neutral pH.
  • If organic co-solvent is required for solubility, limit DMSO to the smallest practical fraction (≤10–20% v/v) and avoid DMF when possible due to persistence concerns.
• Energy and safety:
  • Reactions proceed rapidly at room temperature, often within minutes to hours, minimizing energy use.
  • No metal catalysts are required; avoids heavy-metal waste streams.
• Alternative functional groups (tradeoffs, literature):
  • Vinyl sulfone–PEG: More hydrolytically robust; slower kinetics; broader pH tolerance (7–9). Potentially fewer repeat dissolutions due to longer shelf life in solution.
  • Acrylate–PEG: Less selective; slower; may require higher pH or base catalysis.
  • Iodoacetyl–PEG: Fast and thiol-selective but involves haloacetyl electrophiles with greater aquatic toxicity concerns.

Comparison (literature/general):

• Metric | Maleimide | Vinyl sulfone | Acrylate
• Selectivity for thiols | High (pH 6–7.5) | High–moderate | Moderate
• Hydrolytic stability | Moderate | Higher | Moderate
• Typical solvent | Aqueous | Aqueous | Aqueous/basic
• Catalyst | None | None | Often base

Choose conditions that maximize aqueous content and avoid excess organic solvents while meeting performance targets.

Pharmaceutical Uses

No clinical or therapeutic claims are made. The following describes laboratory/formulation roles reported in the literature for related materials; these are for research use only.

• Excipient/biomaterials roles (literature/general):
  • Hydrogel network former: 8-arm PEG maleimide crosslinks with multi-thiol macromers to form hydrogels used in research on sustained-release matrices, tissue-mimetic scaffolds, and cell encapsulation studies.
  • Surface passivation: PEGylation reduces nonspecific adsorption on device components or analytical surfaces during method development.
  • Conjugation handle: Enables attachment of ligands, imaging agents, or handles to thiol-containing biomolecules for analytical development and in vitro studies.
• Formulation considerations (general):
  • Maintain neutral pH and minimize exposure to moisture prior to use to preserve maleimide content.
  • Filter sterilization (0.22 µm) of aqueous solutions may be feasible depending on viscosity and concentration; confirm no loss of functionality by thiol titration post-filtration.
• Regulatory/pharmacopeia status:
  • Grade, compendial status, and residual limits are Not specified for this item; refer to CoA/Spec Sheet. Multiarm PEGs used in regulated settings typically require detailed control of Mw/Đ, residual solvents/metals, endotoxin/bioburden (if applicable), and identity assays.

Physical Properties

Item-specific measured values are not provided in the Product Data. Do not treat the following as specifications.

• Appearance (item-specific): Not specified for this item; refer to CoA/Spec Sheet. (Multiarm PEG maleimides are typically off-white amorphous solids, literature.)
• Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet. (Offered commercially in various totals, e.g., 5–80 kDa, literature.)
• Solubility (literature/general):
  • Water / aqueous buffers: Typically highly soluble to tens of mg/mL, depending on total MW and temperature.
  • Polar aprotic solvents: Freely soluble in DMSO and DMF; soluble in NMP and acetonitrile to varying extents.
  • Alcohols: Soluble in methanol/ethanol (literature), though maleimide stability is better in neutral aqueous buffers or dry aprotics.
  • Nonpolar solvents: Limited solubility in ethers/alkanes.
• Partitioning (literature): Overall hydrophilic polymer; effective logP not meaningful in the classical small-molecule sense.
• pKa (literature): Maleimide is an electrophile; no relevant acid/base ionization in the coupling range; ring hydrolysis to maleamic acid increases at higher pH.
• Refractive index / density / BP / MP: Not specified for this item; refer to CoA/Spec Sheet. (PEGs are non-volatile polymers; Tg/Tm depend on MW and end groups, literature.)
• Optical/UV (literature): Maleimide shows modest π→π* absorption in near-UV; avoid prolonged light exposure (see Storage).

Quality and Grades

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

How quality is typically defined for 8-arm PEG maleimides (literature/general):

• Molecular weight characterization: Reported as Mn and Mw with dispersity (Đ) by GPC/SEC (often calibrated to PEG standards). For star polymers, the hydrodynamic volume differs from linear PEGs; method notes on calibration are important.
• Degree of functionalization (DoF): Percent of arms bearing active maleimide. Commonly assessed by 1H NMR end-group integration, UV-active derivatization, or thiol consumption assays. High-quality material exhibits DoF approaching 8/8.
• Residuals: Solvent, catalyst, and low-MW impurities are typically controlled; specifics (ppm levels, metal content) are Not specified for this item; refer to CoA/Spec Sheet.
• Moisture/peroxide/UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.
• Stabilization: Some lots are packaged under inert gas (as here) to minimize hydrolysis/oxidation; no additional stabilizers are listed for this item.

What the grade implies (general):

• For bioconjugation and hydrogel formation, grades marketed as “bioconjugation” or “crosslinking ready” emphasize high DoF, low residuals, and narrow Đ for reproducible gelation kinetics and mechanical properties.

Recommendations:

• Review the CoA for Mn/Mw/Đ, DoF, water content, and recommended assay conditions. Confirm reactivity via a small-scale thiol titration before committing valuable biomaterials.

Reaction and Applications

Applications leverage the eight terminal maleimide groups for rapid, chemoselective thiol conjugation.

• Bioconjugation (literature/general):
  • Cysteine-selective coupling to proteins/peptides via Michael addition, forming stable thioether linkages. Optimal at pH 6.5–7.2, where thiolate concentration is sufficient while maleimide hydrolysis is minimized.
  • Site-specific conjugation to engineered cysteines on antibodies, enzymes, or nanobodies. Multivalency allows clustering or multivalent display.
• Hydrogel formation (literature):
  • Thiol–maleimide click crosslinking with multi-thiol macromers (e.g., PEG-dithiol, thiolated hyaluronic acid, peptides with multiple cysteines) to form hydrogels under mild, aqueous conditions. Gelation times tunable by pH, buffer, and catalyst (e.g., weak base).
  • Biomedical research utilities include 3D cell culture scaffolds, microencapsulation, and bioink formulation research (for research use only).
• Surface and nanoparticle modification (literature):
  • Functionalization of thiolated surfaces (gold–thiol SAMs, thiolated silica) to introduce PEG passivation layers with terminal PEG chains.
• Practical tips:
  • Use freshly reduced thiols (e.g., TCEP-treated) and include 1–5 mM EDTA to limit oxidation.
  • Avoid amine buffers (Tris) and pH > 8 to prevent maleimide ring opening.
  • For proteins, degas buffers and work at 4–25 °C; monitor via Ellman’s assay or UV/SEC.
  • For hydrogels, match the molar ratio of thiols to maleimides to near-stoichiometric (r ≈ 1) for maximal crosslink density; small excess thiol can limit defects if DoF < 100%.

Reaction Conditions

General, literature-based guidance for thiol–maleimide coupling and hydrogel formation. These are not item specifications.

• Typical conditions for thiol–maleimide Michael addition:
  • Solvent: Aqueous buffer (phosphate or HEPES, pH 6.5–7.2); optional ≤10–20% DMSO for solubility.
  • Temperature: 4–25 °C (room temperature commonly used). Higher temperatures increase rate but can promote hydrolysis.
  • Time: Seconds to 2 h depending on concentration and temperature.
  • Stoichiometry: For discrete conjugation, 1.0–1.5 equiv thiol per maleimide; for gelation, global thiol:maleimide ratio near 1.0.
  • Catalysts/additives: None required; include 1–5 mM EDTA to suppress metal-catalyzed thiol oxidation. Use TCEP (non-thiol reducing agent) for disulfide reduction when needed.
• Kinetic notes (literature):
  • Apparent second-order rate constants for cysteine–maleimide at pH ~7 are typically 10–10^3 M−1 s−1, depending on nucleophile and environment.
  • Reaction accelerates with increasing pH up to ~7.5 but hydrolysis to maleamic acid also accelerates above neutral pH, reducing effective conversion.
• Workup and analysis:
  • Quench unreacted maleimide with an excess of a low-MW thiol (e.g., cysteine or mercaptoethanol) if necessary.
  • Monitor by Ellman’s assay (thiol consumption), SEC/GPC, SDS-PAGE (proteins), or rheology (gel point). For hydrogels, gelation typically occurs within minutes to tens of minutes at room temperature.
• Stability in solution:
  • Prepare solutions fresh. At neutral pH and ambient temperature, maleimide activity decays over hours to days (literature); refrigeration and light protection extend life but best practice is immediate use.

Safety and Handling

Authoritative safety information must be taken from the product SDS. The following consolidates Product Data with general handling guidance.

• Product Data specifics:
  • Storage: Protect from light; store at −20 °C; argon charged.
  • Shipped: Ice chest + ice pads.
  • GHS classification / pictograms / H-statements / signal word: Not specified for this item; refer to SDS.
• General hazard profile (literature/general):
  • Maleimide end groups are electrophilic and can be irritating to skin, eyes, and respiratory tract; may cause sensitization upon repeated exposure. PEG backbone is generally of low acute toxicity.
• PPE and handling:
  • Wear suitable lab coat, safety glasses, and nitrile gloves. Handle powders to minimize dust/aerosol formation.
  • Work under dry, inert atmosphere when weighing/dissolving to limit hydrolysis of maleimide. Use amber glassware or subdued light.
• Incompatibilities and stability (literature):
  • Avoid amines, strong bases (pH > 8), and nucleophiles that can ring-open or consume maleimide.
  • Avoid prolonged exposure to moisture and light; hydrolysis to maleamic acid reduces reactivity.
  • Thiols and reducing agents (e.g., DTT, BME) will react; keep them absent until intended coupling.
• First-aid overview (general):
  • Skin/eye contact: Rinse with water for at least 15 minutes; remove contaminated clothing; seek medical advice.
  • Inhalation: Move to fresh air; seek medical attention if symptoms persist.
  • Ingestion: Rinse mouth; do not induce vomiting; seek medical attention.
• Waste: Collect aqueous/organic solutions and contaminated disposables as hazardous chemical waste per institutional/municipal regulations.

Solvent Selection

This reagent is a hydrophilic, multi-functional polymer best handled in aqueous buffers or dry polar aprotic solvents.

• Polarity and miscibility (literature/general):
  • Water/aqueous buffers: Typically highly soluble; preferred for bioconjugation and hydrogel formation. Choose buffers without primary amines or thiols.
  • Polar aprotics (DMSO, DMF, NMP): Excellent solvents for stock solutions; ensure they are anhydrous to preserve maleimide activity.
  • Alcohols (MeOH/EtOH): Soluble; use with care due to potential transesterification/base impurities and maleimide stability at higher pH.
  • Nonpolar solvents (Et2O, hexanes): Poor solubility; generally unsuitable.
• Buffer guidance (literature):
  • Phosphate or HEPES, pH 6.5–7.2, 1–5 mM EDTA to chelate metals that catalyze thiol oxidation. Avoid Tris and other amine buffers.
  • Maintain ionic strength compatible with biomolecules (e.g., 50–150 mM NaCl) if used for protein conjugation.
• When to choose alternatives:
  • If extended pot-life in basic media is needed, vinyl sulfone–terminated PEG is more base-stable but less selective than maleimide.
  • For exclusively organic-phase syntheses, acrylate-terminated PEG offers slower, base-catalyzed Michael addition kinetics.

Small comparison (literature/general):

• Maleimide: fastest thiol conjugation at pH ~6.5–7.2; sensitive to hydrolysis.
• Vinyl sulfone: slower, works at pH 7–9; more hydrolytically robust.
• NHS ester: targets amines (lysines) in pH 7.5–8.5 buffers; not thiol-specific; hydrolyzes in water.

Storage and Reconstitution

• Item-specific storage from Product Data:
  • Store at −20 °C, protected from light, argon charged.
  • Shipped in an ice chest with ice pads.
• Container and atmosphere:
  • Keep tightly closed in the original amber container. Maintain inert atmosphere (Ar or N2) after each use to limit moisture/oxygen exposure.
• Handling to preserve activity (literature/general):
  • Allow the sealed container to equilibrate to room temperature before opening to minimize condensation. Open in a dry box or under inert gas if available.
  • Recap promptly; consider storing with a desiccant and backfilling with inert gas.
• Reconstitution guidelines (general):
  • Prepare fresh solutions immediately before use. Dissolve in dry DMSO/DMF for concentrated stocks or directly in neutral, amine-free buffer (phosphate or HEPES, pH 6.5–7.2). Filter (0.22 µm) if needed and compatible.
  • Avoid prolonged standing in aqueous media; maleimide can hydrolyze to maleamic acid. Use within the working session for best performance.
• Aliquoting and freeze–thaw:
  • If stock solutions must be stored, aliquot into dry, amber vials, purge with inert gas, and freeze at −20 °C. Minimize freeze–thaw cycles; discard if loss of reactivity is detected by thiol titration.
• Stability limits:
  • Exact shelf life, water content, and stability-in-solution are Not specified for this item; refer to CoA/Spec Sheet. Periodically verify functionality (e.g., small-scale thiol coupling assay) before critical experiments.

Structure and Identity

Brief overview: 8 Arm PEG Maleimide is a star-shaped, multi-functional polyethylene glycol (PEG) bearing eight terminal maleimide groups for thiol-selective conjugation.

• Item-specific identifiers from Product Data:
  • 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.
  • SMILES / InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
• Structural features (literature/general description):
  • Architecture: A central small-molecule core (commonly a polyol, literature) radiating eight PEG chains (–CH2–CH2–O– repeats) that terminate in maleimide rings.
  • Functional groups: Eight electron-deficient maleimide double bonds (N‑succinimide-like imide with an exocyclic C=C) that undergo rapid, selective Michael addition with thiols; multiple ether linkages along PEG arms; an imide ring at each terminus.
  • Topology: Star polymer (8-arm). No stereocenters in PEG backbone; maleimide ring is planar and conjugated.
  • 2D description in words: Central hub → eight flexible PEG chains → each capped by a five-membered imide ring bearing an activated alkene (maleimide). The termini are the reactive loci; the interior PEG is hydrophilic and typically inert.
• Notes on identity control (literature): Degree of functionalization (DoF ~8/8), number-average molecular weight (Mn), weight-average (Mw), and dispersity (Đ) are the key identity metrics typically provided on CoA for multiarm PEGs.

Synthetic Utility

The eight terminal maleimide groups provide versatile, high-yielding transformations under mild conditions (literature/general):

• Key reactivity:
  • Thiol–maleimide Michael addition: Rapid, chemoselective formation of thioether bonds at pH ~6.5–7.5 without catalysts; cornerstone for bioconjugation and step-growth crosslinking.
  • Post-conjugation stabilization: Base- or nucleophile-promoted ring opening of the succinimide in the thioether adduct to the corresponding maleamic acid is sometimes employed to suppress exchange/retro-Michael processes.
  • Diels–Alder reactivity: Maleimides can participate in DA reactions with dienes (e.g., furan) under appropriate conditions; less common in aqueous bioconjugation but relevant for advanced materials synthesis.
• Retrosynthetic value:
  • Serves as an octavalent electrophilic node in step-growth polymerizations with multi-thiols, enabling network formation with tunable mesh size and mechanical properties.
  • Orthogonality: Maleimide (thiol-reactive) can be combined with other end groups on complementary macromers (e.g., azide/alkyne, NHS esters) for multi-step or sequential functionalization strategies.
• Practical synthesis tips:
  • Verify degree of functionalization via 1H NMR end-group integration or thiol titration prior to multistep assembly.
  • Control stoichiometry (thiol:maleimide ratio) near unity to maximize crosslink density; introduce slight excess thiol to cap defects if DoF < 100%.
  • Work in oxygen-free, neutral buffers to minimize disulfide formation and maleimide hydrolysis; avoid primary amines that can compete or ring-open the imide.

Target Specificity

Not applicable to this product type. 8 Arm PEG Maleimide is a synthetic multiarm polymer and does not have biological target specificity (no antigen, epitope, species reactivity, clone, or isotype). For selectivity in reactions, see the sections on Reaction & Applications and Reaction Conditions (thiol specificity).