PEG3350 Solution (50%, Sterile) - BioReagent

Cat. No.: P1528887

GRADE & PURITY BioReagent

Storage

Store at 2-8°C

Shipped In

Wet ice

Overview

This product is a ready-to-use sterile solution prepared by dissolving polyethylene glycol (PEG3350) in a phosphate buffer system and sterilized by membrane filtration. PEG can modify cell membrane structure, promoting the dispersion and rearrangement of lipid molecules at cell contact sites, thereby mediating cell fusion through lipid bilayer affinity and surface tension. Additionally, PEG can alter cell membrane permeability to facilitate exogenous DNA delivery. This product is suitable for applications including protoplast fusion, yeast competent cell transformation, and nucleic acid/protein precipitation and concentration. It is not recommended for hybridoma cell fusion. For research use only. Not for clinical diagnosis. Important Note This product generally remains as a clear, flowable liquid when stored at 2–8°C. If the temperature approaches 0°C, viscosity may increase; this can be reversed by warming in a 37–55°C water bath. Do not freeze at –20°C.

Specifications

Specifications & Purity

BioReagent

Storage

Store at 2-8°C

Shipped In

Wet ice

This product requires cold chain shipping. Ground and other economy services are not available.

Grade

BioReagent

Product Line

biological_products

Application Protocols

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

General protocol outlines (literature; adapt to your system)

• Protein precipitation (example):
  • Chill buffers and PEG 50% stock to 4 °C.
  • To the protein solution, add 50% PEG stock to reach 10% final PEG and 0.3–0.5 M NaCl.
  • Mix gently, incubate on ice 20–30 min, centrifuge to pellet. Resuspend in appropriate buffer.
• DNA precipitation (PEG/NaCl):
  • Add PEG 3350 to 7.5–10% w/v final and NaCl to 0.5–1.0 M. Incubate on ice 10–20 min, centrifuge. Wash pellet with 70% ethanol, air-dry, and rehydrate.
• Protein crystallization setup:
  • Use the 50% stock to prepare reservoir solutions at 5–30% PEG with buffer/salt. Set up vapor-diffusion drops (1:1 protein:reservoir). Incubate at 4–20 °C and monitor.

Quality/asepsis tips

• Work aseptically to maintain sterility of the stock. Aliquot into sterile containers to minimize freeze–thaw or repeated warming cycles.
• Verify downstream compatibility (salt, pH, additives) before scaling.

Biological Roles

General biochemical context (literature)

• Macromolecular crowding: PEG acts as an inert, volume-excluding polymer that alters the effective activities of proteins and nucleic acids, often increasing association equilibria and affecting folding/assembly.
• Protein stability and solubility: Depending on concentration and protein properties, PEG can either stabilize native states (by preferential exclusion) or promote precipitation/crystallization.
• Osmotic pressure and water activity: PEG solutions change osmotic balance and lower water activity, useful in probing osmoadaptation and hydration effects on biomolecules.
• Phase behavior: PEG participates in aqueous two-phase systems with salts or other polymers, enabling partitioning based on size, charge, and hydrophobicity.
• Cellular workflows: PEG is used in PEG-mediated fusion/transfection protocols in research settings; its nonionic nature reduces direct interactions with membranes compared to cationic polymers, yet transiently perturbs membranes at high local concentrations.

Notes for this product

• The sterile 50% PEG 3350 solution serves as a convenient stock for preparing defined concentrations in biochemical assays. No biological activity is claimed; effects arise from physicochemical crowding and osmotic properties.
• For cell-related experiments, validate endotoxin/bioburden requirements against the lot CoA or perform user-side testing.

Buffer Applications

Applicability

• PEG 3350 is not a classical buffering agent (no defined pKa). It is used as a crowding/precipitating component added to buffers.

Typical use ranges (literature)

• Protein precipitation and crystallization: 5–30% w/v, often in combination with salts (e.g., NaCl, ammonium sulfate) and buffering systems (e.g., 0.1 M HEPES, Tris, acetate) at pH suited to the target protein.
• DNA/RNA workflows: 5–15% w/v with salts (e.g., NaCl, Mg2+) to promote nucleic acid precipitation or phage particle recovery.
• ATPS formation: PEG 3350 with phosphate/sulfate salts or dextran; compositions determined from phase diagrams specific to temperature and ionic strength.

Practical preparation from a 50% stock (general guidance)

• To prepare 10% PEG buffer: For a final volume V, add 0.20×V of 50% stock and 0.80×V of buffer. Mix thoroughly until homogeneous. Adjust pH after PEG addition only if necessary, as viscosity can affect electrode response.
• Order of addition: Dissolve/prepare the buffer first, then add PEG stock slowly with stirring to prevent local overconcentration.
• Filtration: If sterile conditions are critical post-dilution, filter the final solution using a sterile 0.22 μm membrane under aseptic conditions.

Compatibility

• PEG generally does not interfere with buffer pKa. High PEG may affect activity coefficients; titrate empirically for sensitive assays.

Green Alternatives

Context

• PEGs are generally considered low-toxicity, low-VOC, and broadly accepted in green chemistry compared with many organic solvents. For the use case here (aqueous additive/precipitant), environmental and safety profiles are favorable.

Alternative crowding/precipitating agents (literature)

• Glycerol and sucrose: Biodegradable, low hazard; act primarily as stabilizers/osmolytes rather than precipitants at comparable mass fractions.
• Dextran (various MW): Renewable polysaccharide with strong crowding; higher viscosity and potential batch variability.
• PEG 8000: Similar chemistry with higher excluded-volume effect per mass; increased viscosity and potentially different phase behavior.
• Salts (e.g., ammonium sulfate): Highly effective precipitation by salting-out; but introduce high ionic strength and require extensive desalting.

Comparison highlights (general)

• PEG 3350 vs glycerol: PEG offers stronger precipitation/crowding; glycerol excels at protein stabilization without precipitation.
• PEG 3350 vs dextran: PEG is chemically simpler and often less expensive; dextran may better mimic cellular crowding for some systems.
• PEG 3350 vs high ionic strength: PEG avoids extreme conductivity/osmolarity increases but can raise solution viscosity.

Sustainability notes

• Aqueous PEG systems minimize flammability and VOC emissions. Disposal should still follow local regulations; consider reuse/recycling of PEG-containing phases where feasible in process settings.

Pharmaceutical Uses

Scope and restrictions

• This product is labeled For research use only. It is not intended for human or veterinary use, clinical diagnostics, or as an excipient in finished dosage forms.

General formulation context (literature)

• Poly(ethylene glycol) grades, including PEG 3350, are widely used in pharmaceutical manufacturing as excipients: osmotic agents, ointment bases, plasticizers, binders, and processing aids. PEG 3350 (also termed macrogol 3350) appears in pharmacopeial monographs when meeting specific criteria.
• In bioprocessing and analytical development, PEG 3350 is used to concentrate proteins/viruses, in crystallization screens, and to modulate solution viscosity/osmolality.

Considerations for formulation research

• Endotoxin/bioburden: Critical for parenteral or cell-based applications—verify via CoA or perform in-house testing.
• Residuals and impurities: Trace aldehydes/oxidation products can form over time; fresh stocks and proper storage limit risks. Antioxidants are generally not used for PEG solutions in bioprocess research; validate stability as needed.
• Viscosity management: PEG strongly affects rheology; account for shear sensitivity during mixing and filling studies.

Regulatory note

• For any GMP or clinical application, source pharmacopeial-grade material and qualify against the relevant monograph. This specific catalog item provides no such claims beyond BioReagent grade and sterility; consult CoA.

Physical Properties

Item-specific specs

• Concentration: 50% w/v PEG in water (sterile). Further physicochemical specifications (density, viscosity, refractive index, conductivity, pH): Not specified for this item; refer to CoA/Spec Sheet.

Typical properties of PEG 3350 (literature; for neat polymer unless noted)

• Physical state (neat): Waxy solid/flakes at ambient temperature; melts to a viscous liquid.
• Melting range (neat): Often reported around 53–59 °C (literature, varies with polydispersity).
• Solubility: Freely miscible with water; soluble in many polar organics (e.g., lower alcohols); insoluble in nonpolar hydrocarbons.
• Ionization: Nonionic; no pKa (no titratable groups).
• LogP: Not applicable for polymers; PEG is highly hydrophilic.
• Hygroscopicity: Readily retains water; aqueous solutions can absorb CO2 minimally; viscosity strongly temperature-dependent.

Practical notes for 50% solutions (general guidance)

• Handling: Highly viscous; warm gently (e.g., to room temperature or 30–37 °C) to reduce viscosity for accurate pipetting. Avoid overheating to preserve sterility and composition.
• Mixing/Dilution: Add PEG solution slowly to the diluent with gentle stirring to minimize air entrapment and ensure homogeneity.

Always prioritize lot-specific data on the CoA for any numerical specification needed in regulated workflows.

Quality and Grades

Item-specific facts

• Grade: BioReagent
• Sterility: Provided as a sterile 50% solution. Specific sterility assurance level, filtration pore size, bioburden/endotoxin limits: Not specified for this item; refer to CoA/Spec Sheet.

What BioReagent grade generally signifies (general guidance)

• Intended for research and biochemical workflows where low levels of organic/ionic contaminants and particulates are important. Typical use cases include protein chemistry, nucleic acid work, cell biology adjuncts (e.g., macromolecular crowding), and precipitation protocols.

Implications of a sterile, ready-to-use 50% solution

• Convenience and consistency: Minimizes batch-to-batch variability introduced by local dissolution and filtration; reduces contamination risks in sensitive assays.
• Filtration and particulates: Sterile solutions are typically 0.22 μm filtered (literature norm), but verify the exact method for this item on the CoA.
• Endotoxin and bioburden: If your application is endotoxin-sensitive (e.g., cell-based assays), consult the CoA for quantitative limits or perform in-house QC (LAL test) as needed.

Recommended incoming QC (user-side, where critical)

• Visual inspection for clarity, homogeneity, and absence of precipitate/contamination.
• If required by SOPs: pH (if buffered), osmolality, viscosity at a defined temperature, sterility test after opening, and functional qualification in the intended assay (e.g., precipitation efficiency).

Reaction and Applications

Primary research applications (literature/general)

• Protein and nucleic acid precipitation: PEG 3350 (final ~5–20% w/v) is widely used to precipitate proteins, DNA/RNA, and bacteriophage particles (often with salt).
• Macromolecular crowding: Modulates reaction kinetics and equilibria in enzymology and molecular assembly by excluded-volume effects; often used to mimic cellular crowding.
• Protein crystallization: Featured in many crystallization screens as a precipitant; PEG 3350 is a standard component in sparse-matrix screens.
• Aqueous two-phase systems (ATPS): With salts (e.g., phosphate, sulfate) or polymers (e.g., dextran) to partition biomolecules.
• Cell biology workflows: Facilitates certain fusion/transfection protocols (e.g., PEG-mediated transformation or cell fusion, literature). Use only in research contexts consistent with institutional approvals.

Practical tips for using a 50% sterile stock (general guidance)

• Dilution planning: To achieve a final X% w/v PEG, add volume from the 50% stock as Vstock = (X%/50%) × Vfinal. Example: For 10% in 100 mL, use 20 mL of stock and 80 mL of diluent.
• Temperature/viscosity: Warm gently to reduce viscosity; mix thoroughly to ensure homogeneity before aliquoting.
• Salt synergy: For selective precipitation, tune ionic strength (e.g., NaCl, ammonium sulfate) alongside PEG concentration.
• Sterility: Work aseptically if using in cell-based assays or crystallization setups sensitive to contamination.

Chemical reactivity (note)

• While PEG can be chemically functionalized at termini (see Synthetic Utility), the supplied material is an aqueous solution intended for use as an additive rather than as a reactant.

Reaction Conditions

Context

• PEG 3350 in this product is intended as an aqueous additive rather than a reagent for moisture-sensitive synthesis. The following conditions relate to common laboratory uses (literature/general guidance).

Protein/nucleic acid precipitation

• Typical final PEG 3350: 5–20% w/v.
• Temperature: 0–25 °C; lower temperatures often enhance precipitation/selectivity.
• Salts: Add NaCl (e.g., 0.2–1.0 M) or other salts as required by the protocol.
• Time: 10–60 min equilibration, followed by centrifugation.

Protein crystallization

• Screens commonly explore 5–30% w/v PEG 3350 with buffer (pH 4–9) and various salts/additives.
• Temperature: 4–20 °C depending on protein stability.

Aqueous two-phase systems (ATPS)

• Compositions: PEG 3350 with phosphate/sulfate salts or dextran; precise tie-lines from phase diagrams. Mix, allow phase separation (minutes to hours), then collect phases.

Bioconjugation (after PEG activation; literature)

• Solvents: Aqueous buffers (pH 7.5–8.5) for NHS-activated PEG reactions with amines.
• Temperature/time: Ambient, 0.5–4 h typical; protect from hydrolysis.

Notes

• Viscosity strongly affects mass transfer. Ensure thorough mixing and sufficient equilibration. For quantitative protocols, validate with small-scale trials.

Safety and Handling

Item-specific hazard data

• GHS classification, pictograms, signal word, H/P statements: Not specified for this item; refer to the product SDS for authoritative safety information.

General safety profile (literature/typical for PEG aqueous solutions)

• Hazard overview: PEGs are generally regarded as low acute toxicity and low volatility. Aqueous PEG 3350 solutions may cause mild eye or skin irritation upon contact. Not expected to present inhalation hazards under normal liquid handling.
• Incompatibilities: Strong oxidizing agents; reactive acylation/chlorination reagents can functionalize hydroxyl end groups. Avoid contamination that could compromise sterility.
• Thermal considerations: Avoid excessive heating; decomposition can produce irritating fumes.

PPE and handling recommendations (good laboratory practice)

• Wear appropriate PPE: lab coat, safety glasses, and nitrile gloves. Use in a clean environment to maintain sterility when required.
• Spill response: Viscous spills are slippery—contain with inert absorbent, collect mechanically, then wash area with water and detergent.
• First aid (general):
  • Skin/eye contact: Rinse with water for several minutes; remove contaminated clothing. Seek medical attention if irritation persists.
  • Ingestion: Rinse mouth with water. Do not induce vomiting; obtain medical advice.
  • Inhalation: Unlikely; move to fresh air if aerosol/mist exposure occurs.

Disposal

• Dispose of PEG-containing aqueous waste according to institutional and local regulations. Avoid release into drains at high concentrations without authorization.

Solvent Selection

Applicability

• PEG3350 solution is not used as an organic solvent in the classical sense. Instead, it is a hydrophilic polymer additive/cosolute. This section addresses compatibility and selection considerations as a crowding/precipitating agent.

Polarity and miscibility (general)

• PEG 3350 is highly hydrophilic and fully miscible with water across the entire composition range. It is compatible with many aqueous buffers (phosphate, Tris, HEPES) and with moderate concentrations of inorganic salts.
• It can exhibit salting-out synergy with certain salts (e.g., sulfate, citrate, phosphate) to drive phase separation or precipitation.

When to choose PEG 3350 vs alternatives

• Choose PEG 3350 when moderate polymer size is desired for macromolecular crowding, protein/DNA precipitation, aqueous two-phase systems, or crystallization screens.
• Compared with lower-MW PEGs (200–1000), PEG 3350 provides stronger excluded-volume effects at the same mass fraction with typically lower osmotic pressure than very high-MW PEGs (e.g., PEG 8000).
• Alternatives include dextran (for complementary phase diagrams), PEG 8000 (stronger crowding per mass), glycerol/sucrose (stabilizers without strong precipitation), and salts alone (for selective precipitations).

Compatibility notes

• Avoid high concentrations of chaotropes or strong oxidizers with PEG.
• Organic cosolvents (e.g., >10–20% ethanol, isopropanol) can reduce PEG’s efficacy and may cause clouding; evaluate empirically.

Storage and Reconstitution

Item-specific facts (from Product Data)

• Storage: Store at 2–8 °C.
• Shipping: Shipped on wet ice.

General handling guidance

• Do not allow microbial contamination; maintain aseptic technique when accessing the bottle. Reseal promptly.
• Viscosity/solubility: If increased viscosity or phase separation is observed at low temperature, equilibrate to room temperature and mix thoroughly until homogeneous. Gentle warming (e.g., 25–37 °C) can aid mixing; avoid excessive heat.
• Aliquoting: To preserve sterility and reduce repeated temperature cycling, aliquot into sterile, airtight containers upon first use.
• Reconstitution: Not applicable; this is a ready-to-use 50% aqueous solution. If concentration adjustment is required, dilute with sterile, compatible buffer or water.
• Stability/shelf life: Not specified for this item; refer to CoA/Spec Sheet.

Compatibility and materials

• Use compatible plastics or glass; PEG can stress-crack some low-grade plastics over long contact—validate containers for long-term storage.
• Avoid strong oxidizers and reactive acylating agents in storage areas.

For critical applications, verify concentration (e.g., by refractive index, density, or gravimetry) after prolonged storage.

Structure and Identity

Item-specific facts (from Product Data)

• Product: PEG3350 Solution (50%, Sterile), BioReagent grade
• Format: Aqueous solution, 50% w/v polyethylene glycol (PEG), sterile
• CAS/SMILES/InChIKey/CID: Not specified for this item; refer to CoA/Spec Sheet.

General structural description (literature)

• Polymer identity: Poly(ethylene glycol), also known as poly(oxyethylene); a nonionic, linear polyether.
• Repeating unit: –CH2–CH2–O– (ethylene oxide unit).
• End groups: Typically terminal hydroxyls (HO–(CH2CH2O)n–H) in the diol form; actual end-group distribution may vary with supplier/process.
• Average molecular weight: PEG 3350 denotes an average Mn ≈ 3,350 g/mol (literature; polymeric distribution polydisperse).
• 2D/functional features: Flexible, uncharged backbone with ether oxygens spaced every two carbons; high hydrogen-bond acceptor capacity; no ionizable groups under neutral pH; strong hydration shell in water.

Notes on polymer identity

• Exact molecular formula and discrete structure are undefined for polymers and are reported as average values. Consult the CoA for the specific Mw/Mn (if provided) and polydispersity for the supplied lot.

Synthetic Utility

Chemical functionality (general)

• PEG 3350 is a telechelic diol (HO–(CH2CH2O)n–H) in its neat form. Hydroxyl termini enable further derivatization to activate PEG for conjugation (e.g., tosylates/mesylates, carbonates, succinimidyl carbonates, aldehyde after periodate oxidation of glycerol end-caps where present, etc.).

Applications in synthesis/materials (literature)

• PEGylation scaffolds: After end-group activation (e.g., to NHS carbonate), PEG reacts with amines on biomolecules to form carbamates/urethanes.
• Polymer supports/spacers: PEG functions as a hydrophilic spacer in linkers, dendrimers, and surface grafting (e.g., PEGylated surfaces to reduce nonspecific adsorption).
• Phase-transfer and solvent replacement: High-MW PEGs can mimic biphasic behavior with salts (PEG–Na2SO4 ATPS) for catalyst separation; PEG 3350 is sometimes used in "PEGylated catalysis" environments.
• Click-ready PEGs: Azide- or alkyne-terminated PEGs (post-functionalization) participate in CuAAC or SPAAC for bioconjugation.

Relevance to this product

• The supplied material is a 50% sterile aqueous solution intended primarily as an additive. If chemical derivatization is desired, use the neat PEG 3350 solid or appropriately functionalized PEG reagents; aqueous 50% stock is generally unsuitable for moisture-sensitive activation chemistry without prior isolation.

Target Specificity

Not applicable.

• This product is a polymer solution (PEG 3350) and is not a biological targeting reagent (e.g., antibody, ligand, or probe). No target, epitope, clone, species reactivity, or isotype data are relevant.