α‑Hydroxyl‑ω‑Thiol‑poly(D,L‑lactide) (PDLLA‑SH, MW 5K) is linear, mono‑thiol‑terminated fully amorphous biodegradable aliphatic polyester. D‑lactide and L‑lactide repeat units are randomly distributed along polymer backbone, disrupting stereoregularity and eliminating crystalline domains. Compared with MW 2K PDLLA‑SH, this 5 kDa grade exhibits moderate hydrophobicity and intermediate homogeneous hydrolytic degradation rate. One polymer terminus carries reactive free thiol (‑SH) group, the opposite terminus retains inert hydroxyl (‑OH). Terminal thiol supports thiol‑maleimide click coupling, disulfide bond formation and thiol‑ene Michael‑addition reactions, realizing covalent conjugation with maleimide‑modified ligands, peptides and biomolecules under mild conditions. It acts as monofunctional macromonomer for nanoparticle surface modification, redox‑responsive material construction and medium‑term biodegradable biomedical delivery research.
Key Features
- MW: 5000 Da, linear α‑hydroxyl‑ω‑thiol‑terminated poly(D,L‑lactide)
- Fully amorphous non‑crystalline structure, random D/L‑lactide sequence, no melting point
- Moderate hydrophobicity, intermediate and uniform hydrolytic degradation versus 2K PDLLA‑SH
- Excellent biocompatibility; degradation produces non‑toxic lactic‑acid metabolites
- Single terminal free thiol (‑SH) group; compatible with maleimide coupling, disulfide formation and thiol‑ene reaction; opposite polymer end is inert hydroxyl ‑OH
- Narrow molecular‑weight distribution, stable batch‑to‑batch reproducibility; high thiol end‑group functionality
- Soluble in DCM, CHCl₃, THF, DMF, acetone; insoluble in water
- Thiol group is oxidation‑sensitive; strictly avoid air exposure, moisture and heavy‑metal contaminants
Applications
- Monofunctional building block for thiol‑click bioconjugation with maleimide‑activated peptides, ligands and biomacromolecules
- Preparation of redox‑responsive disulfide‑crosslinked PDLLA nanoparticles for medium‑term drug‑delivery research
- Thiol‑functional surface engineering of PDLLA nanocarriers and polymer coatings with medium degradation speed
- Research‑grade raw material for reactive‑site‑modified biodegradable polyester biomaterials
Handling & Storage
- Store at −20 °C under dry inert nitrogen or argon atmosphere; strictly moisture‑proof and oxygen‑shielded
- Keep hermetically sealed; oxygen and moisture trigger thiol oxidation to generate disulfide impurities; avoid repeated freeze‑thaw cycles
- For research‑only use; not intended for clinical or diagnostic applications
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.