HO-PEG4-NH2

Cat. No.: H487634

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

개요

Description

Applications may include: bioconjugation, drug delivery, PEG hydrogel, crosslinker, and surface functionalization

Specifications

법률 정보

Product of JenKem Technology

보관 조건

Store at -20°C

배송

Ice chest + Ice pads

이 제품은 콜드 체인 배송이 필요합니다.지상 및 기타 경제 서비스는 사용할 수 없습니다.

Application Protocols

Not applicable as standardized immunoassay or cell-based protocols. This item is a chemical linker. For general use, see Reaction & Applications and Reaction Conditions for literature-based guidance. Any specific protocols (e.g., coating, coupling) should be validated for the intended system.

Biological Roles

This product is intended for research use only; no medical or clinical claims are made.

General/literature context for PEG-based linkers:

• PEG spacers are widely used in bioconjugation workflows to increase hydrophilicity, reduce nonspecific interactions, and provide spatial separation between a surface and a ligand or between two biomolecular partners.
• The terminal primary amine participates in standard bioconjugation chemistries (amide formation with activated carboxylates, reductive amination with aldehydes), while the terminal hydroxyl can be activated to carbonates/esters for subsequent coupling.
• Short PEG lengths (n≈4) often balance aqueous solubility with minimized flexibility, which can improve presentation of ligands on surfaces or nanoparticles without overly increasing hydrodynamic radius.
• PEG backbones are generally considered biologically inert and resistant to protein adsorption (protein-repellent), contributing to reduced fouling on coated materials in biosensing and diagnostics contexts.

Note: Any use with biological macromolecules (proteins, oligos, lipids) should be validated for the specific system, including assessment of residual reagents and buffer compatibility. Endotoxin/bioburden specifications, if required, must be confirmed on the lot-specific CoA.

Buffer Applications

HO–PEG4–NH2 is not itself a buffering agent. However, buffer choice is critical when using this linker in aqueous couplings (literature guidance):

• For amide couplings to activated esters (e.g., EDC/NHS chemistry):
  • Use amine-free buffers (to avoid competition), such as phosphate (10–50 mM), MES, or HEPES at pH 6.0–7.4. Typical pH for NHS-ester reactions is 7.2–7.5; for EDC activation with carboxylates, activation often performed at pH ~5.0–6.0 (MES), then coupling at neutral pH.
• For reductive amination:
  • Mildly acidic buffers (pH 5.5–6.5, e.g., acetate) enhance imine formation, followed by reduction with NaBH3CN or picoline borane; avoid primary amines (Tris) and strong nucleophiles.
• For carbonate/urea formations in aqueous media:
  • Bicarbonate/carbonate buffers (pH 8.5–9.2) can promote coupling to activated carbonates; monitor to minimize hydrolysis of active species.

Practical tips:

• Filter and degas buffers when performing sensitive conjugations.
• Control ionic strength (50–200 mM) to maintain solubility of both partners; add 5–20% water-miscible cosolvents (MeCN, EtOH) if necessary.

Item-specific buffer compatibility or recommended recipes: Not specified for this item; refer to application notes or CoA as available.

Green Alternatives

From a green chemistry perspective, HO–PEG4–NH2 is itself a benign, non-volatile, and frequently water-compatible linker. Sustainability considerations mainly involve solvent and reagent choices for its use.

• Greener media and methods (literature guidance):

  • Prefer water or water/ethanol mixtures for amide couplings using water-tolerant carbodiimides (EDC) and NHS/TFP activation, avoiding DMF/DCM when feasible.
  • Enzymatic or organocatalytic esterifications/carbamate formations under mild, aqueous or solvent-free conditions can replace classical methods that use phosgene analogs or acid chlorides.
  • Employ solid-supported coupling reagents to simplify work-up and reduce waste.

• Comparison of common approaches:

  | Aspect | Conventional | Greener alternative | Trade-offs | |---|---|---|---| | Amide coupling | DIC or DCC in DMF/DCM | EDC in water/EtOH (buffered) | May need careful pH control; zero-amine buffers (avoid Tris) | | Alcohol activation | Tosylation in DCM/pyridine | Carbonate formation using CDI in MeCN/green esters | CDI generates imidazole byproduct; still requires organic solvent | | Linking via isocyanates | Phosgene-derived reagents | Non-phosgene routes (triphosgene alternatives) or activated carbonates | Reactivity may be lower; longer reaction times | | Purification | Silica flash with chlorinated solvents | Aqueous work-up + RP-HPLC or EtOAc/alcohol mixtures | HPLC has higher energy/water footprint |

• Operational tips:

  • Use minimal solvent volumes and recover/recycle polar solvents where infrastructure permits.
  • Favor catalytic over stoichiometric additives (e.g., DMAP at low loading if required).

Pharmaceutical Uses

No therapeutic claims are made; this product is for research use only.

Formulation/manufacturing context (general/literature):

• Heterobifunctional PEG linkers like HO–PEG4–NH2 are used in process development for constructing conjugates (e.g., linker–payload prototypes, diagnostic reagents, surface coatings) where a short, hydrophilic spacer is desired.
• The primary amine can serve as an anchor to carboxyl-activated components (resins, polymers), leaving the hydroxyl terminus for subsequent activation and attachment to another moiety.
• In preformulation studies, insertion of short PEG spacers may improve aqueous solubility and reduce aggregation of hydrophobic small molecules or peptides in screening assays.
• Regulatory/compendial status: Not specified for this item; refer to CoA/Spec Sheet. PEG oligomers used in GMP contexts require defined specifications for identity, purity, residual solvents, and bioburden/endotoxin if applicable.

Operational considerations:

• Residual coupling reagents (e.g., carbodiimides, NHS) and byproducts must be removed by dialysis, ultrafiltration, or chromatography prior to downstream studies.
• For analytical release, orthogonal tests (NMR, LC–MS, HPLC area%, amine/hydroxyl value) are commonly applied to confirm identity and functionality.

Physical Properties

Item-specific values are not provided for this SKU. Where useful, typical/literature characteristics for HO–PEGn–NH2 oligomers of comparable length (n≈4) are noted for context only.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight (exact): Not specified for this item; refer to CoA/Spec Sheet.
• Melting point / physical state: Not specified for this item; refer to CoA/Spec Sheet. (Literature: short PEG oligomers around n=4 may be low-melting waxy solids or viscous liquids.)
• Boiling point / decomposition: Not specified for this item; refer to CoA/Spec Sheet. (Literature: oligomeric PEGs typically show high boiling points and decompose before distillation at ambient pressure.)
• Density, refractive index: Not specified for this item; refer to CoA/Spec Sheet.
• Solubility (general, literature):
  • Highly soluble in water and polar organic solvents (MeOH, EtOH, MeCN, DMF, DMSO).
  • Limited solubility in nonpolar solvents (hexanes, toluene) due to polarity.
• pKa (literature): Terminal primary amine conjugate acid pKa typically ~9–10; terminal alcohol pKa ~16 (in water, not observable as a Brønsted base). These values guide protection/activation strategies.
• LogP (literature trend): PEGylated oligomers are strongly hydrophilic with low logP; exact value depends on end groups and chain length.

Note: For method development or analytical qualification (HPLC/GC), obtain the item-specific CoA/SDS for authoritative data.

Quality and Grades

• Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.

Context and guidance for this class of materials:

• Typical grades offered for heterobifunctional PEG oligomers include:
  • Synthetic grade: Suitable for general materials synthesis (surface functionalization, polymer modification). Impurity profile focuses on residual solvents, di-/multi-PEG content, and unreacted end groups.
  • Bioconjugation grade: Tighter control of metal/ionic contaminants, residual reagents, and low UV-absorbing impurities; often accompanied by HPLC assay and functionality verification (amine value, hydroxyl value).
  • Anhydrous/low-water packaging: For moisture-sensitive applications (carbamate or activated-ester couplings), materials may be packaged under inert gas with desiccants.

What to check on the CoA/Spec Sheet for your specific lot:

• Assay/purity method (HPLC/GC/NP-HPLC) and specification limits.
• End-group functionality verification (amine value, hydroxyl value, titration results).
• Water content (Karl Fischer), residual solvents, and bioburden/endotoxin if relevant to your workflow.
• Appearance and color limits, and any stabilizers (usually none for short PEG linkers; if present, will be declared).

Reaction and Applications

HO–PEG4–NH2 is a versatile heterobifunctional linker enabling orthogonal derivatization at either terminus. Typical research/materials applications include (literature):

• Surface and particle functionalization:

  • Amine-onto-carboxyl surfaces via carbodiimide chemistry (EDC/NHS) to install PEG spacers improving hydrophilicity and reducing nonspecific adsorption.
  • Hydroxyl-onto-oxide surfaces (SiO2, metal oxides) after silanization or via carbonate formation, enabling tethering of amine-terminated ligands on the distal end.

• Bioconjugation building block (research use only):

  • Amide formation with activated esters (NHS, TFP) on biomolecule surfaces/polymers.
  • Urea/carbamate formation with isocyanates/chloroformates from the hydroxyl or amine end.
  • Reductive amination of aldehyde-functional substrates via the amine terminus (NaBH3CN/borohydride systems).

• Polymer chemistry:

  • Macroinitiator/chain-transfer strategies after converting the hydroxyl to a halide/carbonate/tosylate for subsequent substitution (e.g., ATRP initiator via –O–CO–RCl or tosylate → azide → click).
  • Preparation of heterotelechelic PEGs (e.g., HO–PEG4–N3 via diazotization/azidation of a suitable amine derivative) for CuAAC or SPAAC after further modification.

• Small-molecule assembly:

  • Spacer introduction to modulate aqueous solubility and linker length between pharmacophores, dyes, or handles for affinity tags; the amine allows amide coupling while preserving the terminal alcohol for later activation.

Practical notes:

• Protecting group strategy: Boc/Fmoc for the amine; silyl/carbonate-based protections for the alcohol to achieve selective, stepwise functionalization.
• Control of stoichiometry and sequence: Use orthogonal activation (e.g., NHS-ester coupling at the amine, then activate the alcohol as p-nitrophenyl carbonate) to minimize scrambling.

Reaction Conditions

General literature guidance for typical transformations involving HO–PEG4–NH2. Optimize for your substrates and consult the SDS/CoA for compatibility.

• Amide coupling (amine terminus → carboxylic acid partner):

  • Solvent: DMF, DMSO, or water (EDC/NHS).
  • Conditions: EDC·HCl (1.1–1.5 eq), NHS or TFP (1.1–1.5 eq), pH 7.0–7.5 (phosphate buffer) or anhydrous DMF with HOBt/DIPEA.
  • Temperature/time: 20–25°C, 1–4 h (aqueous) or overnight (organic).
  • Notes: Avoid amine-containing buffers (e.g., Tris) that compete with coupling.

• Reductive amination (amine terminus → aldehyde partner):

  • Solvent: MeOH, EtOH, or phosphate/acetate buffer with 10–30% MeOH.
  • Reagents: NaBH3CN (2–5 eq) or picoline borane; pH 5.5–6.5.
  • Temperature/time: 20–30°C, 2–16 h.

• Alcohol activation to carbonate (alcohol terminus):

  • Reagent: CDI (1.2–2.0 eq) in dry MeCN/DMF, 0–25°C for 1–3 h to form imidazolyl carbonate; then add amine partner with catalytic DMAP.
  • Alternative: p-nitrophenyl chloroformate in DCM with base (pyridine/Et3N), 0–25°C; monitor to minimize overactivation.

• Tosylation/substitution (alcohol terminus → leaving group → azide/halide):

  • TsCl (1.1–1.5 eq), pyridine or Et3N, DCM/DMF, 0–25°C; then NaN3 in DMF (60–80°C) for azidation, followed by Staudinger reduction or CuAAC.

• Purification and analysis:

  • Monitor by LC–MS (ESI), 1H/13C NMR in D2O/DMSO-d6, and HPLC (RP, water/acetonitrile with 0.1% formic acid or NH4HCO3).
  • Short PEGs often give broad NMR signals; rely on end-group diagnostics and MS for confirmation.

Safety and Handling

Always consult the SDS for authoritative safety information. Item-specific GHS details are not provided here.

• GHS classification: Not specified for this item; refer to SDS.

• Signal word / H-statements / pictograms: Not specified for this item; refer to SDS.

• General hazards and precautions (literature/analogous materials):

  • Primary amines can cause skin/eye irritation and may be harmful if inhaled or ingested; avoid aerosol formation.
  • PEG oligomers are generally of low acute toxicity but can cause irritation; handle with standard laboratory hygiene.
  • Hygroscopic: Can absorb moisture and CO2; keep containers tightly closed and use under dry conditions when moisture-sensitive reactions are planned.

• PPE and engineering controls:

  • Use lab coat, safety glasses, and appropriate chemically resistant gloves (e.g., nitrile). Work in a fume hood when weighing or dissolving.

• Incompatibilities (general):

  • Strong oxidizers (may oxidize the alcohol/amine).
  • Strong acids/acid chlorides/anhydrides or isocyanates will react with the amine/alcohol—store separately unless intentional.

• First aid overview (general):

  • Skin/eye contact: Rinse with water for at least 15 minutes; remove contaminated clothing; seek medical attention if irritation persists.
  • Inhalation: Move to fresh air; seek medical attention if symptoms occur.
  • Ingestion: Rinse mouth; do not induce vomiting; seek medical advice.

• Waste: Collect organic aqueous waste according to institutional and local regulations.

Solvent Selection

HO–PEG4–NH2 is not used as a chromatographic solvent; selection here refers to media for dissolution and reactions involving this linker.

• Polarity/miscibility (literature):

  • Highly polar and strongly hydrogen-bonding; readily miscible with water, methanol, ethanol, acetonitrile, DMF, and DMSO.
  • Poor solubility in nonpolar solvents (hexanes, cyclohexane). Limited in toluene unless warmed or co-solvent is used.

• Recommended dissolution media by task:

  • Aqueous work: Water or phosphate/HEPES buffers (pH 6.5–8.5) for amine-coupling to activated esters; avoid buffers containing competing amines (e.g., Tris) during NHS coupling.
  • Non-aqueous coupling: Anhydrous DMF, DCM/DMF mixtures, or DMSO for carbamate/urea/amide formation and for pre-activation of the hydroxyl.
  • Purification aids: Add small amounts of MeOH/MeCN to adjust polarity during flash chromatography on silica; or purify by preparative RP-HPLC when high purity is needed.

• Comparison (literature guidance):

  • PEG2–NH2/OH: Higher reactivity in some cases due to lower steric bulk but shorter spacer and reduced hydrophilicity.
  • PEG8–NH2/OH: Better aqueous solubility and masking/hydrophilization, but increased flexibility/length can affect spatial presentation and may complicate purification.

• Practical tips:

  • For moisture-sensitive couplings, dry the solvent (molecular sieves) and work under inert atmosphere.
  • Prepare concentrated stock solutions (e.g., 50–200 mM) in dry DMF or DMSO, aliquot, and store frozen to minimize freeze–thaw.

Storage and Reconstitution

• Storage (item-specific): Store at -20°C. Protect from moisture. Keep tightly closed.
• Shipping (item-specific): Shipped in an ice chest with ice pads to maintain a cold chain.
• Handling guidance (literature/good practice):
  • Allow container to equilibrate to room temperature before opening to minimize moisture condensation.
  • If frequent use is anticipated, divide into single-use aliquots under dry, inert atmosphere.
• Reconstitution/stock solutions:
  • Solvents: Water, PBS (amine-compatible applications), or anhydrous DMF/DMSO for non-aqueous couplings.
  • Typical stock concentrations (guidance): 10–200 mM depending on application. For NHS-ester couplings, prepare immediately before use to limit hydrolysis of activated partners.
  • Filtration: If needed, sterile-filter aqueous stocks (0.22 µm) for work with sensitive biomolecules; verify that filtration materials are compatible.
• Stability:
  • General: Primary amine and alcohol are stable under neutral conditions; avoid prolonged exposure to strong acids/bases or oxidants.
  • Freeze–thaw: Minimize cycles; store aliquots at -20°C. Thaw on ice or at room temperature and use promptly.

Item-specific limits on water content, stabilizers, or shelf life: Not specified for this item; refer to CoA/Spec Sheet.

Structure and Identity

Heterobifunctional, short-chain polyethylene glycol (PEG) spacer featuring a terminal primary amine and a terminal hydroxyl (HO–PEG4–NH2). Useful as a hydrophilic linker for surface and polymer modification and for assembling conjugates.

• Item-specific identifiers (this SKU):

  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: 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.

• Structural features (general/literature description):

  • Backbone: Four ethylene glycol repeat units [–CH2–CH2–O–]4 providing a flexible, hydrophilic spacer of ca. 1.5–2.0 nm contour length (literature, approximate).
  • Termini: One end is a primary amine (–NH2; nucleophilic, can form amides/ureas/urethanes), the other end is a primary alcohol (–OH; can be esterified, etherified, or converted to activated leaving groups).
  • Functional group polarity: Overall highly polar and water-miscible due to multiple ether oxygens and terminal polar groups.
  • Stereochemistry: Achiral, no stereocenters.

• 2D description in words (general): A linear chain of alternating ethylene and ether linkages ending in –OH on one terminus and –NH2 on the opposite terminus; no ring systems or aromatic units.

Synthetic Utility

Functional handles: terminal primary amine (nucleophilic, basic) and terminal primary alcohol (nucleophilic after activation). The PEG4 spacer provides conformational flexibility and hydrophilicity, enabling diverse transformations (literature):

• Amine-side chemistry:

  • Amide coupling to acids/activated esters (EDC/NHS, HATU, TFFH) to install acyl groups or attach to carboxylated substrates.
  • Urea formation with isocyanates; thioureas with isothiocyanates.
  • Reductive amination with aldehydes/ketones (NaBH3CN, picoline borane) to introduce alkyl groups or link to oxidized polysaccharides.
  • Quaternization or acylation to tune charge/hydrophilicity; protection as Boc/Fmoc/CBz to enable orthogonal sequences.

• Alcohol-side chemistry:

  • Esterification (DIC/DMAP, EDC in aqueous ethanol) to install carboxylate-derived groups.
  • Activation to leaving groups (tosylate, mesylate, imidazolyl carbonate with CDI) followed by SN2 substitution (e.g., azide, halide) to generate click-ready handles.
  • Carbonate/urethane formation with chloroformates or activated carbonates to tether to amines on surfaces or polymers.

• Convergent assembly strategies:

  • Sequential orthogonal couplings (protect amine → modify alcohol → deprotect → second coupling) to build asymmetrically functionalized constructs.
  • Use as a hydrophilic spacer in multipodal scaffolds to reduce intramolecular interactions and improve solubility.

• Retrosynthetic value:

  • Decomposes into well-understood disconnections: amide/urea at the amine end; ester/carbonate/ether at the alcohol end, allowing modular synthesis of libraries with tunable length and polarity.

Target Specificity

Not applicable. This product is a small-molecule/oligomeric linker, not an antibody or affinity reagent. No antigen, epitope, clone, isotype, or species reactivity applies.