Hydroxyl PEG thiol, Mp 3000 (OH-PEG-SH) is a heterobifunctional polyethylene glycol derivative bearing a hydroxyl (-OH) terminus and a thiol (-SH) terminus. The thiol provides a reactive site for attachment to compatible metal surfaces and thiol-selective coupling chemistries, while the hydroxyl terminus remains available for subsequent derivatization.
Synonym: OH-PEG-SH.
The thiol terminus has strong affinity for gold surfaces and can be used to anchor the PEG chain to gold substrates or particles. In solution-phase conjugation, the thiol can also react with appropriately activated thiol-selective groups, including maleimides, under suitable reaction conditions.
Peak molecular weight (Mp) is approximately 3,000 Da. Higher-molecular-weight analogs include Hydroxyl PEG thiol, Mp 5000 and Hydroxyl PEG thiol, Mp 10000. Additional functional PEG derivatives are available through Polysciences' PEG hydrogels and PEGylation solutions.
Key Properties
- Heterobifunctional polyethylene glycol derivative
- Hydroxyl (-OH) functionality at one terminus
- Thiol (-SH) functionality at the opposite terminus
- Peak molecular weight (Mp): approximately 3,000 Da
- Purity: ≥90%
- Polydispersity: ≤1.25
- Soluble in water, chloroform, DCM, DMF, and DMSO
Applications
Gold Surface Functionalization
OH-PEG-SH can be used to modify gold surfaces through interaction of the terminal thiol with the metal substrate. The PEG chain positions a hydroxyl group at the exposed terminus for retention or subsequent derivatization.
Gold Nanoparticle Surface Modification
The thiol terminus can be used to anchor PEG chains to gold nanoparticles and related gold surfaces. Surface coverage and resulting interfacial properties depend on PEG molecular weight, grafting density, particle size, surface condition, and conjugation conditions.
Thiol-Selective Conjugation
The terminal thiol can participate in coupling reactions with suitable thiol-reactive groups, including maleimide-functionalized reaction partners. Reaction efficiency depends on pH, stoichiometry, thiol accessibility, and the condition of the thiol group.
PEG Spacer Introduction
The PEG backbone provides a hydrophilic spacer between a thiol-reactive substrate and the terminal hydroxyl group. Researchers requiring longer PEG chains can compare OH-PEG-SH, Mp 5000 and OH-PEG-SH, Mp 10000.
Compatibility & Bonding Considerations
- Terminal thiol functionality can be used for attachment to compatible gold surfaces
- The thiol can react with suitable maleimide-functionalized molecules under appropriate coupling conditions
- The hydroxyl terminus can be retained or derivatized independently using compatible chemistry
- Soluble in water, chloroform, dichloromethane (DCM), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)
Surface coverage and conjugation efficiency depend on reagent concentration, solvent composition, pH, reaction time, thiol accessibility, surface condition, and the chemistry of the reaction partner. These variables should be controlled when comparing functionalization conditions.
Application Tips
- Select a solvent system that maintains solubility of the PEG derivative and the intended reaction partner or substrate
- Minimize unnecessary exposure of the thiol group to oxidizing conditions before coupling
- For gold-surface modification, use clean substrates and consistent PEG concentration, incubation time, and washing conditions
- For thiol-maleimide coupling, control pH and stoichiometry according to the specific reaction partners
- Verify surface modification or conjugation using analytical methods appropriate for the experimental system
Handling & Storage
- Store at -20°C
- Keep the container tightly closed when not in use
- Store in a cool, well-ventilated location
- Use appropriate laboratory ventilation during handling
- Wear protective gloves, safety glasses, and suitable protective clothing
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FAQ
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1. What is Hydroxyl PEG thiol used for?
Hydroxyl PEG thiol is used in gold-surface functionalization, thiol-selective conjugation, and multistep PEG derivatization. The thiol terminus provides the primary anchoring or coupling functionality, while the hydroxyl terminus can remain unmodified or be derivatized separately.
2. What functional groups are present on OH-PEG-SH?
OH-PEG-SH contains a hydroxyl (-OH) group at one terminus and a thiol (-SH) group at the other. This heterobifunctional architecture provides chemically distinct sites for surface attachment and subsequent modification.
3. Can Hydroxyl PEG thiol be used on gold surfaces?
Yes. The terminal thiol has strong affinity for gold and can be used to anchor the PEG chain to gold substrates or gold nanoparticles. Surface coverage depends on factors including PEG concentration, molecular weight, substrate condition, incubation time, and grafting density.
4. What does Mp 3000 mean?
Mp refers to the peak molecular weight of the polymer molecular-weight distribution. For this grade, Mp is approximately 3,000 Da. Higher-molecular-weight grades include Mp 5000 and Mp 10000.
5. What are the purity and polydispersity specifications for Hydroxyl PEG thiol, Mp 3000?
Hydroxyl PEG thiol, Mp 3000 has a purity specification of ≥90% and polydispersity of ≤1.25. See the product specification for current quality requirements. For larger quantities, request a bulk quote.
Safety & Documentation
Store Hydroxyl PEG thiol, Mp 3000 at -20°C and use appropriate laboratory ventilation, protective gloves, eye protection, and suitable protective clothing during handling. See the Safety Data Sheet (SDS) for complete handling, storage, and safety information and the product specification for molecular-weight, purity, and polydispersity requirements. Related functional PEG materials are available through Polysciences' PEG hydrogels and PEGylation solutions.
