mPEG-Cholesterol,MW 2000 , CAS No.M1439988

CAS: M1439988 Cat. No.: M1439988 분자량: 2000.00

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

개요

mPEG-Cholesterol,MW 2000 is a PEG derivative which self-assembles in water to form micelle-like structure. The cholesterol tail can be used to encapsulate hydrophobic drugs while the PEG chain ehances the water solubility of the micelles.

Specifications

보관 조건

Store at -20°C

배송

Ice chest + Ice pads

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이름과 식별자

분자량

2000.00

Application Protocols

The following are generalized, literature-based protocols for research formulation. Adjust to your system; these are not item-specific validated procedures.

• Protocol A: Micelle preparation (aqueous)

  1. Warm HEPES buffer (20 mM, pH 7.4) to 50 °C.
  2. Add mPEG–cholesterol to 2 mg/mL while stirring.
  3. Sonicate in a bath sonicator for 5–10 min until clear.
  4. Optional: load hydrophobic probe by adding a small volume of its DMSO stock (<2% v/v final) during step 2.
  5. Filter through 0.22 μm PES and cool to room temperature.

• Protocol B: Thin-film hydration for PEGylated liposomes

  1. Dissolve desired lipids (e.g., 55 mol% PC, 40 mol% cholesterol, 5 mol% mPEG–cholesterol) in CHCl3:MeOH (3:1).
  2. Evaporate solvent in a round-bottom flask; dry under high vacuum ≥2 h.
  3. Hydrate with PBS at 60 °C (volume to reach 5–10 mg/mL total lipid) with vortexing.
  4. Perform 5 freeze–thaw cycles; extrude through 200 nm then 100 nm membranes.
  5. Characterize by DLS and phosphorous assay; store at 4 °C for short term.

• Protocol C: Ethanol injection (chlorinated-solvent-free)

  1. Prepare a 10 mg/mL ethanolic solution of mPEG–cholesterol (± co-lipids).
  2. Inject into 4 volumes of PBS with rapid stirring at room temperature.
  3. Dialyze (MWCO 3.5 kDa) against PBS to remove ethanol; change buffer 3× over 24 h.

Note: Composition ratios and temperatures are typical literature values and should be optimized. Avoid clinical use; research only.

Biological Roles

• Research context only (no clinical claims). The following describes general behaviors of PEG–cholesterol amphiphiles in biochemical systems (literature/general):

• Membrane interaction

  • The cholesterol anchor inserts into lipid bilayers, leveraging native sterol–phospholipid interactions. This can modulate bilayer order, reduce fusion, and provide a handle for presenting a hydrated PEG brush at the membrane–solution interface.

• Colloidal stabilization and protein resistance

  • Surface-presented PEG creates steric repulsion and hydration layers that reduce nonspecific protein adsorption and aggregation, aiding in the stability of liposomes, proteoliposomes, and other nanoparticles used in biochemical assays.

• Self-assembly and cargo handling

  • In aqueous media above the CMC, mPEG–cholesterol self-assembles into micelles or mixed assemblies that can encapsulate hydrophobic probe molecules, facilitating biophysical measurements or delivery in cell-free systems.

• Tuning interfacial properties

  • By adjusting the mol% of PEG–lipid in lipid mixtures, researchers can systematically vary membrane curvature preference, fusogenicity, and interaction with biomacromolecules.

• Compatibility considerations

  • Nonionic nature is generally compatible with a wide range of buffers and salts. However, high ionic strength and serum proteins can screen steric stabilization; empirical optimization of PEG–lipid content is recommended for each assay.

Buffer Applications

This product is not a buffering agent and is not used to set or maintain pH. However, it is commonly dispersed or hydrated in biological buffers for formulation work (general guidance):

• Common hydration buffers

  • HEPES (10–20 mM, pH 7.2–7.5) or PBS (1×, pH 7.2–7.4) for liposome and micelle preparations.
  • For metal-sensitive assays, use chelexed buffers or add 0.1–1 mM EDTA to minimize adventitious catalysis of oxidation.

• Practical notes

  • Warm buffer to 40–60 °C to aid hydration of thin films containing mPEG–cholesterol.
  • Gentle bath sonication or brief probe sonication can reduce initial aggregate size; avoid overheating.
  • Sterile work: filter final dispersions through 0.22 μm PES when compatible with your system.

Green Alternatives

• Solvent/process choices (general sustainability guidance)

  • Prefer ethanol or isopropanol over chlorinated solvents for dissolution and nanoparticle formation. Where possible, use aqueous ethanol (e.g., 70–90%) with controlled injection to minimize solvent load.
  • Replace high-boiling amide solvents (DMF, NMP) with DMSO or alcohols when feasible.
  • Employ solvent-recycling rotovaps and closed systems to reduce VOC emissions.

• Material alternatives and design trade-offs (literature/general)

  • Alternative anchors: phytosterol- or tocopherol-anchored PEGs may offer renewable feedstocks, though membrane behavior can differ.
  • Biodegradable linkers: carbonate or ester linkages can render PEG–lipids hydrolyzable; conversely, ether linkages increase stability but decrease degradability. Choose based on end-of-life and application needs (exact linkage of this item is Not specified for this item; refer to CoA/Spec Sheet.).
  • Alternative hydrophiles: polysarcosine- or poly(2-oxazoline)-cholesterol conjugates can provide PEG alternatives with potentially different environmental and biological profiles.

• Comparison snapshot (general)

  • Ethanol injection vs chloroform film hydration:
    • Ethanol injection: greener, scalable, fewer hazardous residues; may need optimization for particle size.
    • Chloroform hydration: robust co-dissolution; requires thorough solvent removal and carries higher EHS burden.

Adopt greener laboratory practices without compromising data quality by validating alternative solvents and processing parameters on small scale first.

Pharmaceutical Uses

For research and development use only. No medical or clinical claims are made. The following describes formulation roles in a laboratory/pharmaceutics context (literature/general):

• Excipient/function roles

  • PEGylated sterol amphiphile providing steric stabilization in liposomes, lipid nanoparticles, and micelles.
  • Helps control particle size, reduce aggregation, and modulate surface properties during process development studies.

• Process compatibility

  • Amenable to ethanol-based processes (ethanol injection, microfluidics), thin-film hydration, and remote loading workflows. Residual solvent control and removal steps should be validated.

• Regulatory considerations

  • mPEG–cholesterol does not have a compendial monograph to our knowledge; for translational work, source GMP-grade materials with full characterization (Mn/Mw/Ð, residuals, bioburden/endotoxin) and perform extractables/leachables assessments.

• Comparators/alternatives

  • PEGylated phospholipids (e.g., DSPE–PEG2000) provide a two-chain anchor with different membrane residence times compared to sterol anchors; choice influences in vivo-like stability and release kinetics in preclinical models.

• Stability notes

  • Linkage stability (ether > carbamate ≳ carbonate > ester, in general) affects shelf-life and in-process robustness; confirm the specific linkage of your lot (Not specified for this item; refer to CoA/Spec Sheet.).

Physical Properties

• Item-specific data (from Product Data)

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Nominal Mn ≈ 2000 g/mol (polymer average)

• Typical properties for mPEG2000–cholesterol (literature/general — not item specifications)

  • Physical state: waxy solid to off-white solid at ambient temperature; softens near PEG Tg.
  • Solubility: amphiphilic; soluble in polar organics (DMSO, DMF, ethanol, isopropanol, methanol), chlorinated solvents (CHCl3, DCM), and co-solvent mixtures with water. Dispersible in aqueous buffers above critical micelle concentration (CMC) with gentle heating/sonication.
  • Critical micelle concentration (CMC): typically low micromolar to sub-micromolar range for PEG–cholesterol conjugates (exact CMC depends on linkage and medium; verify experimentally for your formulation).
  • Density: ~1.05–1.15 g/mL (PEG-rich solids; indicative only, linkage-dependent).
  • Glass transition (PEG-rich): Tg typically around −50 to −30 °C; softening near room temperature may occur when hydrated.
  • Partitioning: behaves as a nonionic amphiphile; hydrophilic–lipophilic balance governed by PEG length (mPEG2000 confers good aqueous compatibility while retaining strong membrane anchoring via cholesterol).

Note: Precise BP/MP, refractive index, logP, pKa are not generally defined for polymers of this type; item-specific values are Not specified for this item; refer to CoA/Spec Sheet.

Quality and Grades

• Item-specific grade/purity (from Product Data)

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

• What to look for in PEG–cholesterol quality (general guidance)

  • Molecular weight and dispersity (Ð): PEG is polydisperse; verify Mn/Mw and Ð by GPC. A narrower Ð can improve batch-to-batch performance in self-assembly and membrane incorporation.
  • Residual solvents and volatiles: assess by GC; low residual solvent is important for biological formulations.
  • Identity and linkage confirmation: verify by 1H/13C NMR (sterol resonances, PEG –CH2– signals), FTIR (C=O if carbonate/carbamate/ester), and MS (MALDI-TOF for polymer average).
  • Functional end groups: mPEG is methoxy-capped; minimal residual hydroxyl or reactive ends reduces unintended crosslinking. If reactive chemistry is required, select NHS-, maleimide-, azide-, or alkyne-terminated PEG–cholesterol instead of mPEG–cholesterol.
  • Inorganic/metal content and water: for sensitive applications, check ICP-OES and KF titration on the CoA when available.

• Stabilizers/antioxidants

  • Unless otherwise stated, mPEG–cholesterol is typically supplied without added stabilizers. If antioxidants are used for specific lots, this will appear on the CoA. Their presence may affect biological assays and should be disclosed in methods.

• Documentation

  • Refer to the lot-specific CoA/Spec Sheet for assay/purity method, Mn/Mw/Ð, residual solvent, and water content. These are Not specified for this item; refer to CoA/Spec Sheet.

Reaction and Applications

• This material is primarily a formulation component rather than a small-molecule reagent for classical synthetic reactions. Nevertheless, it has broad research applications (literature/general):

• Self-assembly and nanostructures

  • Forms micelles and mixed micelles with other amphiphiles; the cholesterol anchor promotes insertion into lipid bilayers, while mPEG provides steric stabilization and reduced protein adsorption.
  • Used in liposomes and lipid nanoparticles (LNPs) to present a PEG corona, adjust surface hydration, and modulate colloidal stability and aggregation kinetics.

• Membrane engineering

  • Cholesterol-anchored PEG can insert into pre-formed lipid membranes, supported lipid bilayers, and vesicles to tune membrane rigidity, reduce fusion, and control surface interactions.

• Cargo solubilization

  • Hydrophobic pockets within sterol-rich micelles/nanoparticles enable solubilization of poorly water-soluble research compounds for in vitro studies.

• Surface modification

  • Nonfouling coatings on hydrophobic surfaces; adsorption or hydrophobic insertion via cholesterol with PEG chains providing brush layers.

• Notes on chemical reactivity

  • mPEG terminus is methoxy-capped (non-reactive). For covalent bioconjugation, select functional derivatives (e.g., Chol–PEG–NHS, –maleimide, –azide) rather than mPEG–cholesterol.
  • Avoid strong acids/bases and oxidants during processing; these can cleave or oxidize the linkage and PEG backbone.

• Practical tips

  • Ensure accurate mass ratios in multicomponent lipid systems; small deviations in PEG–lipid content can markedly change particle size and polydispersity.

Reaction Conditions

Classical reaction condition guidance is not directly applicable because this product functions as an amphiphilic excipient rather than a small-molecule reagent. The following application conditions are provided as general literature-based guidance for assembly and formulation:

• Thin-film hydration (liposomes/mixed vesicles)

  • Dissolve lipids (e.g., phosphatidylcholines, cholesterol, and mPEG–cholesterol) in chloroform:methanol (2–4:1). Cast a thin film under reduced pressure; dry under high vacuum ≥2 h. Hydrate with buffer (HEPES or PBS, pH ~7.4) at 40–60 °C with agitation. Optional: size by freeze–thaw cycles and extrude through 100–200 nm membranes.

• Ethanol injection (micelles/LNP precursors)

  • Prepare a 5–20 mg/mL ethanolic solution of mPEG–cholesterol (and other lipids if used). Inject into aqueous buffer (room temp to 37 °C) under vigorous stirring at controlled organic:aqueous ratios (e.g., 1:3 to 1:10 v/v). Remove ethanol by dialysis or tangential flow filtration.

• Direct aqueous dissolution (micelles)

  • Add polymer to warm buffer (40–60 °C) to reach 0.1–10 mg/mL. Sonicate briefly to clarity. Allow to equilibrate at room temperature before use.

• Stability considerations

  • Avoid strong acids/bases and oxidative conditions; maintain neutral pH. If the linkage is hydrolyzable (ester/carbonate), limit exposure to >60 °C in water.

Note: Temperatures, times, and ratios are general literature ranges and should be optimized for your system. They are not item-specific specifications.

Safety and Handling

• Item-specific hazard information (from Product Data)

  • GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.

• General safety guidance for mPEG–lipid amphiphiles (literature/general)

  • Expected hazards: nonionic polymer–lipid; typically considered of low acute toxicity but may cause mechanical irritation to eyes/skin or respiratory tract if dust/aerosol is generated.
  • PPE: lab coat, safety glasses or face shield, nitrile gloves. Use a fume hood when weighing or dissolving powders to avoid inhalation of particulates or solvent vapors.
  • Handling: avoid dust generation; ground and bond containers when transferring organic solutions. Prepare aqueous dispersions with appropriate containment to prevent slips/spills.
  • Incompatibilities: strong oxidizers and strong acids/bases can degrade PEG or linkage; avoid prolonged exposure to elevated temperatures and UV/ozone which can promote oxidation.
  • Thermal/oxidative stability: PEG segments can slowly form peroxides upon air/UV exposure in solution; store solutions under inert headspace when possible and add antioxidants only if compatible with application.
  • First aid (overview; defer to SDS):
    • Inhalation: move to fresh air; seek medical advice if symptoms persist.
    • Skin/eye contact: rinse with water for several minutes; remove contaminated clothing; obtain medical attention if irritation continues.
    • Ingestion: rinse mouth; do not induce vomiting; seek medical advice.
  • Spill response: collect solids by gentle sweeping; for solutions, contain with inert absorbent. Dispose in accordance with institutional and local regulations.

Always consult the product’s SDS for authoritative safety data and emergency procedures.

Solvent Selection

• Polarity and miscibility (general/literature)

  • Amphiphilic, nonionic. Soluble in many polar organics and chlorinated solvents; dispersible or soluble in water depending on temperature, concentration, and presence of co-solvents/surfactants.

• Recommended solvents by task

  • Thin-film/liposome prep: chloroform or chloroform:methanol (2–4:1) for co-dissolving with phospholipids; remove solvent under vacuum to form thin film, then hydrate with buffer.
  • Micelle/NP prep without chlorinated solvents: absolute ethanol or isopropanol; inject into aqueous buffer (ethanol injection) or remove alcohol by dialysis.
  • Stock solutions for screening: DMSO (10–100 mg/mL) with subsequent dilution into aqueous media.
  • Aqueous dispersions: HEPES, PBS, or tris buffers (pH 7–7.5) often used; gentle heating (40–60 °C) and sonication improve clarity.

• Comparison (general guidance)

  • Ethanol vs chloroform: ethanol is greener and compatible with GMP-friendly processes but may give larger initial aggregates; chloroform provides excellent co-solubility with many lipids yet is hazardous and less sustainable.
  • DMSO vs DMF: DMSO is less volatile and more biocompatible for cell-facing experiments; DMF offers strong solvency but is typically avoided in biological contexts.

• Practical tips

  • Filter organic stocks (0.22 μm PTFE) before film formation.
  • Avoid prolonged exposure to aqueous solutions at high temperature, which can accelerate hydrolysis if the linkage is ester/carbonate (exact linkage for this item is Not specified for this item; refer to CoA/Spec Sheet.).

Storage and Reconstitution

• Item-specific storage and shipping (from Product Data)

  • Storage conditions: Store at −20 °C.
  • Shipped in: Ice chest + Ice pads.
  • Research use note: For research use only.

• General storage guidance for mPEG–cholesterol (literature/general)

  • Keep tightly closed in the original container with desiccant; protect from light.
  • Allow vial to warm to room temperature in a desiccator before opening to minimize moisture condensation.
  • For long-term storage, maintain under inert gas (argon/nitrogen) when feasible to limit oxidative degradation of PEG/linkage.

• Reconstitution and stock solutions (general)

  • Organic stocks: dissolve at 10–100 mg/mL in ethanol, isopropanol, DMSO, DMF, chloroform, or CHCl3:MeOH (verify compatibility with downstream use). Filter through 0.22 μm PTFE for clarity.
  • Aqueous dispersions: prepare 0.1–10 mg/mL in HEPES or PBS. Warm to 40–60 °C and sonicate gently to aid dissolution/dispersion. For sterile applications, 0.22 μm filter (PES) after formation.
  • Avoid repeated freeze–thaw of aqueous dispersions; aliquot and store at 4 °C for days to weeks depending on formulation. For dry material, minimize thaw cycles by aliquoting powder under dry atmosphere.

• Stability checks

  • Monitor for changes in appearance, particle size (DLS), and NMR/FTIR signatures over time. If unusual odor/color develops or performance drifts, prepare fresh material.

Note: Any item-specific specifications (water content, residual solvents, exact linkage) are Not specified for this item; refer to CoA/Spec Sheet.

Structure and Identity

A methoxy-terminated polyethylene glycol covalently conjugated to a cholesterol moiety; an amphiphilic PEG–lipid designed for self-assembly and membrane anchoring.

• Item-specific identifiers (from Product Data)

  • SKU: M1439988
  • Product name: mPEG-Cholesterol, MW 2000
  • 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: Nominal Mn ≈ 2000 g/mol (polymer average; exact value and dispersity per lot on CoA)

• Structural features (general/literature)

  • Hydrophilic segment: linear methoxy-PEG (mPEG) chain, typically ~45 ethylene oxide units for Mn ≈ 2 kDa, capped at the α-end with –OCH3.
  • Hydrophobic anchor: cholesterol (tetracyclic sterol core: fused A/B/C/D rings with a C8 aliphatic side chain at C17 and 3β-hydroxyl native position derivatized for linkage).
  • Linkage: commonly ether, carbonate, carbamate, or ester connecting PEG to the 3-position of cholesterol (exact linkage for this item: Not specified for this item; refer to CoA/Spec Sheet.).
  • Amphiphile topology: single hydrophobic sterol + single PEG tail; forms micelles or inserts into bilayers.
  • Stereochemistry: cholesterol moiety retains native steroidal stereochemistry (multiple defined stereocenters in the steroid framework). 2D depiction would show a long PEG chain terminating in methoxy on one end and tethered to the sterol nucleus on the other.

Synthetic Utility

This material is not typically used as a reagent for small-molecule synthesis due to its methoxy-capped PEG terminus and sterol anchor. Nevertheless, it has utility in materials and surface chemistry (general):

• Building block for soft materials

  • Serves as a preformed amphiphile for constructing micelles, vesicles, and mixed assemblies; useful in templated polymerizations or mineralization studies where a steric brush is desired.

• Surface modification

  • Hydrophobic insertion of the cholesterol anchor into polymeric or inorganic surfaces (e.g., hydrophobic-modified silica, polystyrene) can provide a PEG corona that reduces fouling in analytical devices.

• Limited covalent derivatization

  • Because the PEG α-end is methoxy-capped, further functionalization typically targets the cholesterol/linker region or requires different starting materials (e.g., hydroxyl-PEG–cholesterol or reactive-ended PEG–cholesterol derivatives). Choose the appropriately functionalized analog for bioconjugation.

• Retrosynthetic perspective

  • The conjugate embodies a hydrophobic anchor + hydrophilic spacer motif common in surfactant design; selection among ether/carbonate/carbamate/ester linkers tunes hydrolytic stability and processing latitude.

Target Specificity

Not applicable. This product is a nonionic amphiphile, not a biological targeting reagent (e.g., antibody, ligand). No antigen/epitope specificity data apply.

자주 묻는 질문

How should this product be stored?

Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.

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 are the CAS number, molecular formula and molecular weight?

The CAS Number is M1439988, and the molecular weight is 2000.00 g/mol.

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.