PLLA3000-PEG5000-Thiol

Cat. No.: P1443346

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Panoramica

PLLA3000-PEG5000-Thiol is a polylactic acid derivative that forms micelles in water and initiates biodegradation by attacking ester bonds through hydrolysis. PLLA3000-PEG5000-Thiol can be used in drug delivery research.

Specifications

Condizioni di conservazione di stoccaggio

Store at -20°C

Spedito in

Ice chest + Ice pads

Questo prodotto richiede spedizione a catena fredda. I servizi di terra e altri servizi economici non sono disponibili.

Application Protocols

Item-specific validated protocols are not provided. Below are generalized, literature-based workflows for this class of materials; adjust to your system.

1. Thiol–maleimide conjugation (aqueous):

• Dissolve polymer (1–5 mg/mL) in 50 mM phosphate buffer, pH 6.8–7.0; add ≤10% DMSO if needed.
• Degas; add 1 mM TCEP; equilibrate 10 min.
• Add maleimide-activated partner (1.1 equiv per –SH). React 1–2 h at RT.
• Quench residual maleimide with cysteine; purify by dialysis (MWCO selected above polymer Mn) or SEC.

2. Micelle preparation (nanoprecipitation):

• Dissolve polymer at 10 mg/mL in acetone or THF; optionally dissolve hydrophobic cargo in the same solution.
• Inject into 10× volume of water/PBS under vigorous stirring.
• Stir 30–60 min to evaporate organic; polish by 0.22 µm filtration; characterize by DLS and TEM.

3. Gold nanoparticle coating:

• Mix polymer solution (0.05–0.5 mg/mL in water/ethanol) with citrate-stabilized AuNPs.
• Incubate 1–4 h; salt-age gradually to improve grafting density; purify by centrifugation/resuspension.

Quality checks (general): SEC/GPC for Mn shifts, Ellman’s assay for residual –SH, 1H NMR for conjugate ratio, DLS for particle size/PDI, and UV/Vis if chromophores are present.

Biological Roles

This product is a synthetic polymer for laboratory research. It does not possess intrinsic biological activity, but its components impart useful properties in biological contexts (literature/general):

• PEG segment:

  • Provides hydrophilicity and steric stabilization, reducing nonspecific protein adsorption and aggregation of colloids.
  • Confers “stealth” behavior to nanoparticles, prolonging circulation in model systems (conceptual; no clinical claims).

• PLLA segment:

  • Biodegradable aliphatic polyester; hydrolyzes to lactic acid under aqueous conditions, with rates dependent on crystallinity, pH, and temperature.
  • Hydrophobic core-former for micelles that can solubilize lipophilic compounds.

• Thiol functionality:

  • Enables site-selective conjugation to maleimide-functional biomolecules (enzymes, peptides, proteins) and immobilization on gold surfaces for biosensor model systems.

• Use scenarios (research context only):

  • Formation of polymer–biomolecule conjugates to study ligand density, binding, or targeting in vitro.
  • Preparation of core–shell nanoparticles for uptake, trafficking, or release studies in cell-free or cell culture assays (no therapeutic claims).

Item-specific biological testing data are not provided. Researchers should perform their own biocompatibility, endotoxin, and residual-solvent assessments appropriate to the intended in vitro or ex vivo studies.

Buffer Applications

This material is not a buffering agent. However, buffer choice strongly influences conjugation and self-assembly behavior (literature/general guidance):

• Conjugation buffers:

  • Thiol–maleimide coupling: Use 50 mM phosphate or HEPES, pH 6.5–7.2. Avoid primary amines (e.g., Tris) that can react with activated esters if present in the system. Include 1–5 mM EDTA to chelate metal ions that catalyze thiol oxidation.
  • Maintain a low concentration of a non-nucleophilic reducing agent (e.g., 0.5–2 mM TCEP) to keep thiols reduced; avoid excess DTT/βME that can compete in coupling.

• Micelle preparation/dispersions:

  • PBS (pH 7.4) or HEPES-buffered saline is commonly used. Ionic strength affects particle size and colloidal stability.
  • Temperature near or below room temperature helps maintain micelle integrity for PEG–PLLA systems; gentle stirring minimizes shear-induced aggregation.

• pH effects (general):

  • Acidic or basic conditions accelerate PLLA hydrolysis; for stability during handling, use near-neutral buffers.

Item-specific buffer compatibility, pH stability windows, and CMC are not provided for this product; consult the CoA/Spec Sheet and verify experimentally for your system.

Green Alternatives

Selecting greener solvents and methods can reduce environmental impact while preserving performance (literature/general guidance).

• Greener solvent swaps for processing:

  • Replace CHCl3/CH2Cl2 with 2-MeTHF or ethyl acetate for dissolution and film casting when solubility allows.
  • Use acetone or IPA/water mixtures for nanoprecipitation in place of halogenated systems.

• Aqueous/benign media for conjugation:

  • Conduct thiol–maleimide coupling in phosphate or HEPES buffer (pH 6.8–7.2) with minimal DMSO cosolvent (<10%) and oxygen exclusion.

• Energy and waste minimization:

  • Favor room-temperature couplings (thiol–maleimide proceeds rapidly without heating).
  • Use dialysis or ultrafiltration over repeated precipitation to remove small-molecule byproducts.

• Comparison snapshot (literature/general):

  • CHCl3 vs 2-MeTHF: similar solvency for polyesters; 2-MeTHF is biomass-derived, lower toxicity, but may require inhibitor management and careful drying.
  • DMF/DMSO vs aqueous buffers: DMF/DMSO offer broader solubility; buffers reduce toxicity but may slow reactions or induce micellization.

Note: Actual solvent feasibility depends on this polymer’s lot-specific solubility and intended application. Pilot small-scale trials are recommended before process changes. Item-specific green attributes are not specified; refer to CoA/Spec Sheet.

Pharmaceutical Uses

For research use only. No medical or clinical use is claimed or supported.

In a formulation-development context (literature/general), PEG–PLLA–thiol block copolymers are investigated as:

• Excipient scaffolds for nanoformulations: forming micelles or nanoparticles that encapsulate hydrophobic actives; PEG corona imparts steric stabilization while PLLA provides a degradable core.
• Surface modifiers: Thiol-mediated attachment to gold or maleimide-activated substrates to control surface hydrophilicity and protein adsorption in device prototyping.
• Crosslinkable components: Via thiol–ene chemistry to create degradable hydrogels or coatings for release studies.

Practical formulation notes (general):

• Residual solvents, monomers, catalysts, and endotoxin levels must be assessed for any use involving biological samples. Item-specific impurity limits are not provided; refer to CoA/Spec Sheet.
• Control end-group fidelity and Mn/Đ to ensure reproducible particle size and release kinetics.
• Stability studies should monitor thiol oxidation (disulfide formation) and PLLA hydrolysis, which can alter performance during storage.

Pharmacopeial status, compendial monographs, or DMF availability are not specified for this item; consult Aladdin Scientific for regulatory documentation if needed for nonclinical development work.

Physical Properties

Item-specific specifications are not provided for this listing. For definitive values, consult the CoA/Spec Sheet. General/literature characteristics for PLLA–PEG–thiol materials are provided for planning only.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Density (bulk polymer, literature/general): typically ~1.1–1.3 g/cm³ depending on block ratio and crystallinity.
• Glass transition and melting (literature/general):
  • PEG block: Tm ~50–65 °C (for high-MW PEG); Tg ~−60 °C.
  • PLLA block: Tg ~55–65 °C; Tm ~150–180 °C (values shift with block lengths and crystallinity).
• Solubility profile (literature/general):
  • Good: chloroform, dichloromethane, tetrahydrofuran, dioxane, dimethylformamide, dimethyl sulfoxide.
  • Limited/aggregation: water (forms micelles; CMC depends on block sizes), alcohols (partial).
  • Insoluble: aliphatic hydrocarbons.
• Critical micelle concentration (CMC, literature/general): typically low micromolar for PEG–PLLA diblocks; depends strongly on block MWs and temperature.
• Partitioning (literature/general): Amphiphilic; PEG block confers hydrophilicity (hydrodynamic corona), PLLA forms hydrophobic domains/cores.
• Viscosity (solution, literature/general): increases sharply above CMC and with concentration; relevant for nanoprecipitation and film casting.

Important: Do not treat literature values as specifications. Actual thermal transitions, CMC, and solubilities depend on exact Mn, dispersity, end-group content, and processing history of this specific lot.

Quality and Grades

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

• Typical quality attributes for functional block copolymers (literature/general):

  • Molecular weight (Mn) and dispersity (Đ) by GPC/SEC with appropriate calibration (e.g., PEG or polystyrene standards) and verification by NMR end-group analysis.
  • End-group functionality: Free thiol content quantified (e.g., Ellman’s reagent) to confirm availability for conjugation; residual protecting groups ruled out.
  • Residual monomers/solvents/catalysts: Determined by GC/HPLC/ICP as applicable; low levels are preferred for life-science research uses.
  • Moisture and peroxide content: Important for oxidative stability of thiols and for reproducible micellization; when critical, verified on the lot CoA.

• What grade means in practice (general guidance):

  • “Life science/research” grade polymers typically emphasize biocompatible impurities profile, controlled end-group fidelity, and consistent block ratios, enabling reproducible nanoparticle formation and conjugation efficiency.

• Stabilizers/additives:

  • Presence/absence of antioxidants (e.g., small amounts of BHT) or reducing agents for thiol preservation should be indicated on the CoA if used. Not specified for this item; refer to CoA/Spec Sheet.

• Buyer tips:

  • Request lot-specific data: Mn, Đ, PEG/PLLA ratio, %–SH, residual solvent, and any stabilizer. These govern CMC, particle size, and coupling yields.

Reaction and Applications

With a terminal thiol, PLLA3000–PEG5000–Thiol serves as a versatile conjugation scaffold and self-assembling amphiphile.

• Chemoselective conjugations (literature/general):

  • Thiol–maleimide Michael addition: Rapid, near-quantitative coupling at pH 6.5–7.5 to maleimide-bearing dyes, peptides, or surfaces.
  • Thiol–ene/yne “click”: UV- or radical-initiated addition to alkenes/alkynes for network formation or surface grafting.
  • Au–S interactions: Robust adsorption to gold nanoparticles/surfaces for corona formation and stabilization.
  • Disulfide formation: Oxidative coupling to form dimeric polymers (reversible linker for redox-responsive systems).

• Self-assembly and nanoformulation (literature/general):

  • Forms core–shell micelles in water (PLLA core, PEG shell); useful for encapsulating hydrophobes in the core.
  • Enables nanoprecipitation, solvent displacement, and thin-film hydration methods to generate nanoparticles, often 20–200 nm depending on block sizes/concentration.

• Materials uses (literature/general):

  • Surface modification: PEG corona imparts antifouling/stealth properties; thiol enables attachment to maleimide-activated biomolecules or gold.
  • Hydrogel and film formation: Crosslink via thiol–ene for degradable networks; cast films from volatile solvents for barrier/coating studies.

• Practical tips:

  • Maintain thiol in reduced state (argon blanket, add 0.5–5 mM TCEP) before coupling.
  • Control pH and ionic strength to balance colloidal stability vs. reaction rate.
  • Verify coupling by UV/Vis (if chromophore attached), Ellman’s assay, or GPC shift (general guidance).

Reaction Conditions

General literature guidance for common reactions of thiol-terminated PEG–PLLA; adjust to your system and verify experimentally. Item-specific conditions are not provided.

• Thiol–maleimide coupling:

  • Solvent: aqueous phosphate/HEPES buffer pH 6.5–7.2; 0–20% DMSO/DMF cosolvent if needed.
  • Temperature: 20–25 °C.
  • Stoichiometry: 1.05–1.2 equiv maleimide per –SH.
  • Time: 0.5–4 h; monitor by Ellman’s assay or disappearance of maleimide UV band.
  • Notes: Exclude oxygen; include 0.5–2 mM TCEP (avoid amine buffers that can add to maleimide).

• Thiol–ene click (radical-mediated):

  • Solvent: CHCl3, THF, or bulk; or aqueous with surfactant/cosolvent.
  • Photoinitiator: Irgacure 2959 (aqueous) or DMPA (organic), 0.1–1 wt% relative to polymer.
  • Light: 320–365 nm UV; 5–30 min depending on thickness and intensity.
  • Notes: Control oxygen inhibition; post-cure wash to remove residual initiator.

• Disulfide formation:

  • Solvent: aqueous buffer pH 7–8 or MeOH/H2O.
  • Oxidant: air/O2 (slow), or mild oxidants (e.g., diamide); monitor viscosity/SEC.

• Gold surface immobilization:

  • Medium: ethanol/water or buffer; 0.01–1 mg/mL polymer; 1–12 h incubation.
  • Rinse to remove physisorbed chains; validate by contact angle or SPR.

• Micelle preparation (nanoprecipitation):

  • Dissolve polymer in acetone/THF (5–10 mg/mL); add dropwise to water (≥10× volume) under stirring; evaporate solvent; size by DLS.

These are representative literature conditions; optimize per substrate and desired outcome.

Safety and Handling

• Item-specific GHS data: Not specified for this item; refer to SDS for authoritative safety information.

  • Signal word: Not specified for this item; refer to SDS.
  • GHS classification/pictograms: Not specified for this item; refer to SDS.

• General safety considerations for PLLA–PEG–thiol polymers (literature/general):

  • Low volatility solid; exposure is primarily via dust/particulate. Avoid inhalation; handle as a nuisance particulate.
  • Thiol end-group may have characteristic odor and is susceptible to oxidation to disulfides; minimize exposure to air/oxidants.
  • PEG and PLLA are generally regarded as low acute toxicity polymers; nonetheless, avoid ingestion and skin/eye contact.

• PPE and engineering controls (good laboratory practice):

  • Wear safety glasses, lab coat, and appropriate gloves (nitrile). Work in a fume hood during weighing/dissolution, especially when using organic solvents.
  • Avoid dust generation; use antistatic measures if dry handling.

• Incompatibilities (general):

  • Strong oxidizers (thiol oxidation), strong bases/acids (can accelerate ester hydrolysis of PLLA), and isocyanates/anhydrides (may react with terminal groups).

• First-aid overview (general):

  • Inhalation: move to fresh air; seek medical attention if irritation persists.
  • Skin/eye contact: rinse with water for 15 minutes; remove contaminated clothing; obtain medical advice if needed.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical attention.

Always consult the product’s SDS for definitive hazard, exposure limits, and disposal guidance.

Solvent Selection

This amphiphilic diblock requires thoughtful solvent choice based on task (film casting vs. micelle formation vs. conjugation).

• Polarity/miscibility (literature/general):

  • Organic solvents: High solubility in CHCl3, CH2Cl2, THF, dioxane, DMF, DMSO; useful for processing, thin films, and nanoprecipitation.
  • Aqueous media: Disperses as micelles or aggregates (PLLA core, PEG corona); direct water dissolution is limited below the CMC.
  • Alcohols: Partial solubility; isopropanol/ethanol can serve as nonsolvents for nanoprecipitation.

• Practical selection by application (general):

  • Micelles/nanoprecipitation: Dissolve polymer in THF or acetone, inject into water (or PBS) under stirring; remove organic by evaporation/dialysis.
  • Conjugation (thiol–maleimide): Use aqueous buffer pH 6.5–7.0 with 10–50% co-solvent (DMF/DMSO) if needed to keep polymer dispersed; exclude oxygen.
  • Film casting/coatings: CHCl3 or CH2Cl2 provide fast evaporation; THF for more uniform films.

• Small comparison (literature/general):

  • CHCl3: excellent solubility; toxic, halogenated.
  • THF: good solvency; peroxide former; easier removal.
  • DMSO/DMF: strong solvency; high bp; helpful for bioconjugations.
  • Water/PBS: green medium; requires surfactant-like self-assembly.

Note: Item-specific solvent specs are not provided; validate solubility with a small-scale test and consult the CoA/Spec Sheet as needed.

Storage and Reconstitution

• Item-specific storage: Store at −20 °C (from Product Data).

• Shipping: Ice chest + ice pads (from Product Data) to limit thermal exposure.

• General handling and stability (literature/general):

  • Protect from moisture, oxygen, and light to minimize PLLA hydrolysis and thiol oxidation.
  • Store in tightly sealed, moisture-barrier containers with desiccant under inert gas (N2/Ar) when possible.
  • Avoid repeated freeze–thaw; aliquot upon receipt.

• Reconstitution guidelines (general):

  • For organic processing: dissolve in dry CHCl3, THF, DCM, DMF, or DMSO at 5–50 mg/mL; gentle warming (≤40 °C) may aid dissolution.
  • For aqueous use: prepare micelles by solvent-switch or thin-film hydration; direct dissolution may require sonication above the CMC.
  • For conjugation: use deoxygenated buffer (pH 6.5–7.2) with 0.5–2 mM TCEP to maintain free thiol.

• Stability notes:

  • Monitor for disulfide formation (loss of –SH by Ellman’s assay) and molar mass changes (SEC) during storage.
  • Acidic/basic environments accelerate PLLA degradation; keep near neutral pH during aqueous work.

• Specifications not provided for this item (consult CoA/Spec Sheet): appearance, exact Mn/Đ, stabilizers, residual solvents, moisture content. Always equilibrate to room temperature in a desiccator before opening to prevent condensation.

Structure and Identity

A thiol-terminated amphiphilic block copolymer comprising a poly(L-lactic acid) block (PLLA) and a poly(ethylene glycol) block (PEG), with a terminal –SH functionality for conjugation.

• Item-specific facts (from Product Data/name):

  • Polymer type: PLLA–PEG block copolymer with thiol end-group
  • Nominal block sizes: PLLA3000–PEG5000 (approximate number-average molecular weights inferred from name)
  • 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 applicable to polymers of undefined length; not specified for this item.

• Structural features (general polymer-chemistry description):

  • Backbone motifs: Aliphatic polyester segment (PLLA; –[CH(CH3)–CO–O]–n–) covalently linked to a polyether segment (PEG; –[CH2–CH2–O]–m–).
  • Stereochemistry: PLLA block derived from L-lactide; repeating units are stereoregular (isotactic) in the polyester segment (literature/general).
  • Functional end-group: One terminus bears a thiol (–SH) for chemoselective conjugation (e.g., to maleimides, acrylates, Au surfaces). Other termini are typically hydroxyl/alkoxy depending on synthesis (literature/general).
  • 2D description: Linear A–B diblock copolymer: hydrophobic PLLA segment connected to hydrophilic PEG segment; terminal –SH available at one end for coupling.

• Notes on identity testing (general):

  • Typical characterization uses 1H/13C NMR (block ratios), GPC/SEC (Mn, Đ), FTIR (ester/ether bands), and Ellman’s assay for free thiol quantification (literature/general).

Synthetic Utility

As a functionalized diblock, PLLA3000–PEG5000–Thiol operates as a modular macromolecular building block (literature/general):

• End-group reactivity:

  • –SH couples selectively to maleimides (Michael addition) and participates in thiol–ene/yne chemistry, enabling post-polymer modification and network formation.
  • Thiol can be oxidized to disulfides, providing redox-responsive linkages in polymer–polymer or polymer–payload assemblies.

• Macromolecular synthesis roles:

  • Serves as a macro-monomer in click-based step-growth polymerizations or as a crosslinker in photopolymerized networks.
  • Anchors to gold surfaces/nanoparticles for constructing hybrid organic–inorganic materials with PEG brushes and degradable anchors.

• Self-assembly as a synthetic tool:

  • Generates core–shell micelles/vesicles which function as nanoreactors or carriers for hydrophobic reagents, enabling compartmentalized reactions.

• Retrosynthetic considerations:

  • Choice of block lengths (here nominal PLLA3000/PEG5000 per name) tunes CMC, aggregate morphology, and mechanical properties of resultant materials.
  • End-group fidelity is critical; confirm thiol presence before downstream chemistry (e.g., Ellman’s test) to avoid incomplete coupling.

Item-specific synthetic specifications (Mn, Đ, functionality %) are not provided; obtain lot-resolved data from the CoA to design stoichiometries and predict assembly behavior.

Target Specificity

Not applicable. This product is a synthetic polymer, not an antibody or affinity reagent.

• Antigen/epitope, clone, isotype, and species reactivity: Not applicable.
• Any target-binding properties would arise only from ligands you conjugate to the thiol; no inherent biological target specificity is provided with this item.