mPEG benzaldehyde - MW 2000 Da

Cat. No.: M163982

GRADE & PURITY MW 2000 Da

Storage

Room temperature

Shipped In

Normal

Specifications

Specifications & Purity

MW 2000 Da

Storage

Room temperature

Shipped In

Normal

Application Protocols

No vendor-validated application protocols are provided for this specific item.

General procedural outline (literature; adapt to your system):

• Prepare a fresh mPEG-CHO stock (e.g., 10–100 mM) in water, DMSO, or buffer compatible with the chosen ligation chemistry.
• For hydrazone/oxime coupling: mix with the hydrazide/aminooxy partner in acetate buffer (pH 5.0–6.0), optional 10–50 mM aniline, react 2–6 h at room temperature; purify by dialysis or SEC.
• For reductive amination to amines: pre-equilibrate in phosphate buffer (pH ~7), allow imine formation (0.5–2 h), then add a suitable reducing agent; quench and purify.

Because performance is substrate- and MW-dependent, run small-scale screens to optimize stoichiometry, pH, temperature, and reaction time. Always consult the SDS and CoA for item-specific constraints.

Biological Roles

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

Literature/general context:

• Poly(ethylene glycol) (PEG) is widely used as an inert, hydrophilic spacer that reduces nonspecific interactions, increases solubility, and provides a steric shield on biomolecular surfaces.
• The benzaldehyde end-group enables chemoselective ligation to nucleophilic functionalities (hydrazide, aminooxy, primary amines) introduced on proteins, peptides, carbohydrates, or cell-surface glycoconjugates in research settings.
• In biophysical studies, PEGylation modulates hydrodynamic radius, decreases aggregation, and can tune binding kinetics by entropic exclusion near surfaces.
• In cell/material interfaces, PEG layers minimize protein adsorption and fouling, allowing controlled display of ligands distal to the surface through the aryl aldehyde linkage chemistry.

Notes:

• The reagent is for research use only. No medical or clinical claims are made or implied.
• Biological performance (e.g., conjugation efficiency, retained activity of biomolecules) depends on PEG molecular weight, end-group conversion, degree of labeling, and reaction conditions; verify experimentally for each system.

Buffer Applications

This product is not a buffering agent and is not typically used to prepare classical buffer systems.

Practical note (literature/general): For conjugation, it is commonly used in compatible buffers:

• Hydrazone/oxime ligation: sodium acetate or citrate buffer, pH 4.5–6.5; optional aniline catalyst (10–50 mM) to accelerate reactions.
• Imine formation with amines (followed by reduction): phosphate or HEPES buffer near neutral pH (6.5–7.5) with minimal primary amine content; avoid Tris during coupling. After imine formation, apply reductive amination using water-compatible reducing agents.

Always tailor buffer ionic strength and pH to the biomolecule’s stability and intended reaction pathway.

Green Alternatives

Consider greener choices in solvent, catalysts, and coupling handles (literature/general):

• Solvent selection:

  • Prefer water or aqueous buffers for hydrazone/oxime ligations; limit DMSO/DMF to minimal cosolvent percentages.
  • Ethanol can substitute for methanol in organic phases as a greener protic solvent.

• Reducing agents/catalysts:

  • Picoline borane or pyridine–borane are effective alternatives to sodium cyanoborohydride, avoiding cyanide. Select based on toxicity profiles and waste handling policies.
  • Organocatalysts such as aniline accelerate oxime/hydrazone formation at low loading; consider less hazardous derivatives (e.g., p-anisidine) and minimize catalyst concentration.

• Alternative coupling handles:

  • Oxime/hydrazone bioconjugation can be performed without reduction, yielding water-stable linkages under mildly acidic conditions—often more aqueous and additive-light than reductive amination.
  • If aldehyde avoidance is desired, mPEG-azide with Cu-free click (DBCO/BCN) partners or mPEG-thiol for Michael additions can reduce reliance on reducing agents.

Comparison snapshot (general):

• Parameter | Benzaldehyde end-group | NHS ester | Azide/Click
• Water compatibility | Good (esp. hydrazone/oxime) | Moderate (hydrolyzes) | Good
• Need for reductant | Optional (hydrazone/oxime); yes for imine→amine | No | No
• Byproducts | Minimal; borate salts if reduced | NHS, hydrolysis products | None significant

Balance tradeoffs against target substrate, pH tolerance, and downstream purification.

Pharmaceutical Uses

Item-specific pharmacopeial status or excipient grade: Not specified for this item; refer to CoA/Spec Sheet.

Literature/general (formulation/manufacturing research context only):

• PEGylation reagents like mPEG benzaldehyde are employed in process development studies to explore conjugation routes to proteins/peptides or to functionalize surfaces (e.g., filters, resins) to mitigate fouling and tailor adsorption.
• As a polymeric modifier, mPEG end-capped with benzaldehyde can be used to prepare model PEG–amine linkages through reductive amination, informing scale-up strategies and purification workflows.
• Surface engineering: installing PEG layers on medical-material analogs during research can evaluate hydrophilicity, lubrication, and biofouling resistance characteristics of candidate materials.

Note: For research use only. No therapeutic or clinical use is intended or implied by this listing.

Physical Properties

Item-specific physicochemical specifications (BP/MP/density/UV cutoff/purity/logP/pKa/refractive index/solubility): Not specified for this item; refer to CoA/Spec Sheet.

Literature/general expectations for mPEG-benzaldehyde (qualitative; polymer-MW dependent):

• Physical state: typically white to off-white solid or waxy flakes/powder; glass transition and softening strongly depend on molecular weight.
• Solubility: highly soluble in water and polar organics (MeOH, EtOH, acetone, acetonitrile, DMSO, DMF); limited solubility in nonpolar hydrocarbons; aromatic end-group can improve solubility in moderately polar organics (literature/general).
• Viscosity: aqueous and organic solutions can be viscous at high concentration; viscosity increases with MW (literature/general).
• Vapor pressure/boiling point: not applicable as a nonvolatile polymer; aldehyde end may have characteristic aromatic absorption in UV (approx. 250–280 nm), but solution spectra depend on MW and concentration (literature/general).
• Stability: aldehydes can oxidize to the corresponding benzoic acid and hydrate in water; rate minimized under neutral, oxygen-limited, and low-light conditions (literature/general).

Practical notes (general):

• Prepare solutions freshly for conjugation chemistry to minimize background oxidation/hydration of –CHO.
• Filter solutions (0.22 µm) if particulate is observed; mild warming (≤40 °C) can aid dissolution for higher-MW grades.

Quality & Grades

Item-specific grade/purity, stabilizers, and metal/UV specifications: Not specified for this item; refer to CoA/Spec Sheet.

General guidance (literature/industry practice):

• PEG functional reagents are commonly offered as research grade with control over: average molecular weight (Mn), polydispersity (Đ), aldehyde end-group conversion (>90–98% typical), and residual solvents/reagents. Verify these on the provided CoA.
• What “mPEG benzaldehyde” implies: methoxy-capped PEG bearing a single benzaldehyde terminus—optimized for bioconjugation (imine/hydrazone/oxime formation) and surface modification.
• Stabilizer implications: These reagents are typically supplied without added stabilizers to preserve –CHO reactivity. If any stabilizer or antioxidant is present, it will be listed on the CoA; assess compatibility with your application.
• Analytical verification: End-group titration (e.g., hydroxylamine assay), NMR end-group analysis, GPC for Mn/Đ, and residual aldehyde oxidation (acid content) are common QC elements (literature/general).
• What to check before use:
  • Target Mn (e.g., 2k/5k/10k) matches your protocol.
  • Moisture content and residual solvents suit your process.
  • End-group conversion and aldehyde integrity meet your coupling efficiency needs.

Reaction & Applications

This reagent is designed for end-group conjugation via the benzaldehyde functionality while leveraging PEG’s solubility and biocompatibility (literature/general).

Key application families:

• Schiff base formation with primary amines (R–NH2) followed by in situ reductive amination to stable secondary amines. Common reductants: sodium cyanoborohydride, picoline borane, pyridine–borane, or sodium triacetoxyborohydride in appropriate media.
• Hydrazone and oxime ligations with hydrazides (R–NH–NH2) and aminooxy groups (R–ONH2), respectively; typically proceed efficiently at pH 4.5–6.5 and can be catalyzed by aniline derivatives.
• Polymer/materials coupling: immobilization onto amine-functional surfaces (e.g., polymers, silica, nanoparticles) to install PEG coatings, reduce fouling, or tune interfacial properties.
• Macromolecular PEGylation: site-selective conjugation to proteins bearing introduced hydrazide/aminooxy handles (via periodate-oxidized glycans or EDC/NHS pre-functionalization), enabling stealthy, water-soluble conjugates for research.

Practical tips (general):

• Maintain mildly acidic to neutral pH for imine/hydrazone formation; avoid strong base. For amine targets, follow with reductive stabilization.
• Use freshly prepared solutions to minimize aldehyde oxidation to benzoic acid; sparge with inert gas if feasible.
• Typical stoichiometry: 2–10 molar equivalents of mPEG-CHO per reactive site for biomolecules; optimize based on accessibility and MW of PEG.
• Monitor reaction by SDS-PAGE (for proteins), MALDI/ESI-MS (for small conjugates), or NMR/GPC for polymer coupling.

Reaction Conditions

General conditions (literature guidance; optimize empirically):

1. Hydrazone/Oxime Ligation

• Substrates: mPEG-CHO with hydrazide or aminooxy partners.
• Solvent: aqueous acetate/citrate buffer (50–200 mM), pH 4.5–6.5; ≤10–20% DMSO or DMF if needed.
• Catalyst: aniline or p-anisidine (10–50 mM) can accelerate; optional.
• Temperature/time: 20–25 °C for 1–6 h; complete in 2–24 h depending on sterics.
• Workup: desalting, dialysis (MWCO chosen by PEG size), or precipitation into cold ether/acetone for polymer conjugates.

2. Imine Formation + Reductive Amination

• Substrates: primary amines (proteins, polymers) with mPEG-CHO.
• Solvent: phosphate or HEPES buffer, pH 6.5–7.5; avoid primary amine buffers (e.g., Tris) during coupling.
• Reductant: sodium cyanoborohydride (1–10 mM) or picoline borane (10–50 mM) added after initial imine formation; maintain pH 6–7 for selectivity.
• Temperature/time: 20–25 °C, 2–18 h; gentle agitation.

3. Organic-phase Couplings

• Solvent: dry DMF/DMSO/MeOH/EtOH depending on partner solubility.
• Additives: molecular sieves (3 Å) can drive imine formation by water removal.
• Monitoring: NMR for small-molecule adducts; GPC for macromolecular shifts.

Yields: Typically high for small-molecule conjugates (literature) and variable for biomolecules depending on accessibility and degree of labeling; verify by appropriate analytics.

Safety & Handling

GHS/SDS classifications for this specific item (signal word, H-statements, pictograms): Not specified for this item; refer to SDS.

General safety considerations for PEG aldehydes (literature/general):

• Hazard profile: PEG backbones are generally of low acute toxicity; aromatic aldehydes can be irritants and sensitizers. Avoid inhalation of dust and contact with eyes/skin.
• PPE: use lab coat, safety glasses, and appropriate gloves (e.g., nitrile). Handle powders in a fume hood or with local exhaust to minimize dust exposure.
• Incompatibilities: strong oxidizers (risk of aldehyde oxidation), strong bases/acids (can catalyze side reactions such as aldol self-condensation of aldehydes or acetal formation), reducing agents in storage (may reduce –CHO). Keep away from reactive amines during storage unless intended for conjugation.
• Special risks: aldehydes can slowly oxidize to acids upon air/light exposure; protect from air and light during prolonged handling. PEGs can form peroxides only at very low levels relative to ethers with activated α-positions; nevertheless, avoid unnecessary prolonged storage with air exposure (literature/general).
• First-aid overview: rinse skin/eyes with water for several minutes in case of contact; remove contaminated clothing; if inhaled, move to fresh air; if ingested, rinse mouth. Seek medical attention as needed. Always defer to the SDS for authoritative measures.
• Spill/cleanup: collect solids by gentle sweeping; for solutions, absorb with inert material. Avoid discharge to drains.

Solvent Selection

This PEGylation reagent is amphiphilic: the PEG chain confers water/polar-organic solubility; the benzaldehyde end adds slight hydrophobicity.

• Polarity/miscibility (literature/general):

  • Water: typically freely soluble; solubility increases with lower MW.
  • Polar protic: MeOH, EtOH—excellent solvents for stock solutions and small-molecule conjugations.
  • Polar aprotic: DMSO, DMF, NMP—excellent for concentrated stocks; miscible with aqueous buffers upon dilution.
  • Moderately polar: acetonitrile, acetone—often good; check MW-dependent solubility.
  • Nonpolar: poor to limited solubility (hexanes, toluene), though the aryl end can marginally improve toluene solubility relative to pure mPEG.

• Practical selection tips (general):

  • For protein/biomolecule conjugation: prepare stocks in DMSO or aqueous buffer (pH 5–7) and dilute into the reaction buffer to ≤10% organic co-solvent to maintain biomolecule integrity.
  • For surface modification or polymer coupling: DMF/DMSO aid wetting of hydrophobic substrates while maintaining PEG solubility.
  • Avoid strongly basic aqueous media during storage/use to limit aldehyde hydration/side reactions.

• Comparison (literature/general):

  • mPEG-benzaldehyde vs mPEG-propionaldehyde: aryl aldehydes form imines more readily and are often more stable, enabling faster conjugation at near-neutral pH.
  • mPEG-benzaldehyde vs mPEG-NHS: NHS esters require basic pH and are water-labile; benzaldehyde handles allow chemoselective ligations with hydrazide/aminooxy groups at mildly acidic pH.

Storage & Reconstitution

Item-specific storage/shipping (from Product Data):

• Storage conditions: Room temperature.
• Shipped in: Normal.

Additional best-practice guidance (literature/general; do not override the above):

• Keep container tightly closed, protected from moisture and light to preserve –CHO integrity. Use a desiccant in long-term storage.
• After opening, purge headspace with inert gas if possible and reseal promptly.
• For solution stocks: prepare in dry solvent (water, DMSO, DMF, or alcohols as appropriate) at convenient concentrations; store aliquots at 2–8 °C or −20 °C if compatible with your workflow to minimize repeated freeze–thaw. Avoid prolonged storage of aqueous stocks due to aldehyde hydration/oxidation.
• Reconstitution: allow solid to warm to ambient in a desiccator before opening; dissolve with gentle stirring. Mild warming (≤40 °C) can aid dissolution of higher-MW grades.
• Stability checks: monitor by NMR or functional assay (e.g., hydroxylamine titration) if stored for extended periods.

Research Use Note: For research use only.

Structure & Identity

Overview: mPEG benzaldehyde (often written mPEG-Ph-CHO) is a methoxy-terminated poly(ethylene glycol) bearing a terminal benzaldehyde group for Schiff-base–type bioconjugation.

• Item-specific identifiers (CAS, MF, MW, SMILES, InChIKey): Not specified for this item; refer to CoA/Spec Sheet.
• Polymer nature: This is a polydisperse PEG macromolecule with a single active end-group. Exact average molecular weight and dispersity (Đ) are lot-dependent (literature/general).
• Structural features (literature/general):
  • Backbone: repeating –CH2–CH2–O– units (polyether).
  • Termini: one end is methoxy-capped (–OCH3), the other end is para- (or general aryl-) benzaldehyde (–C6H4–CHO or –C6H5–CHO linker depending on design).
  • Functional group: aromatic aldehyde capable of forming imines/hydrazones/oximes.
  • Typical 2D description: linear PEG chain terminating in an aryl ring bearing a formyl (–CHO) substituent; distal terminus capped with methoxy.
• Stereochemistry: None (achiral repeat units; no defined stereocenters) (literature/general).
• Notation guidance (literature/general): Repeat unit shown as (–O–CH2–CH2–)n; end-group as –O–(PEG)n–O–CH3 (methoxy end) and –O–(PEG)n–Ar–CHO (benzaldehyde end).

Synthetic Utility

From a synthetic perspective, mPEG benzaldehyde serves as a monofunctional macromolecular building block (literature/general):

• Key reactivity: electrophilic aldehyde suitable for forming imines, hydrazones, and oximes; subsequent reduction yields stable secondary amines covalently attaching the PEG chain to nucleophilic substrates.
• Polymer-supported chemistry: acts as a soluble polymer support—facilitates purification by precipitation/dialysis and enables phase-switch strategies.
• Materials/linker synthesis: enables installation of PEG spacers onto amine-bearing polymers (polyamides, polyethylenimine), silica (via aminosilanes), or nanoparticles, tuning dispersibility and interfacial properties.
• Protection/derivatization: aldehyde can transiently form imines/hydrazones as protecting or reversible anchoring groups in aqueous-compatible settings; oxime linkages offer enhanced hydrolytic stability without reduction.
• Orthogonality: compatible with many bio-orthogonal chemistries; the PEG chain is typically inert to mild coupling conditions (EDC/NHS on separate handles, click reactions if dual-functional designs are used).

Considerations:

• Control stoichiometry to avoid crosslinking when substrates are multi-amine polymers.
• Choose PEG molecular weight to balance solubility, steric shielding, and analytical tractability (GPC, MALDI).

Target Specificity

This is not an antibody or affinity ligand with defined biological target specificity.

Item-specific target/epitope/clone/isotype information: Not applicable and not specified for this item.

Frequently Asked Questions

How should this product be stored?

Store at room temperature.

How is this product shipped?

This product ships under standard ambient conditions. No temperature-controlled packaging is required.

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.