Sitting between fast‑eroding 2 K and medium‑molecular‑weight 5 K carboxyl‑terminated PCL grades, this 3 kDa polymer strikes a practical balance of crystallinity, solvent compatibility and hydrolytic degradation timeline. Its terminal carboxylic acid group can be readily activated via EDC/NHS chemistry to form stable amide linkages with amine‑containing peptides, protein fragments and small‑molecule ligands. Compared with MW 2 K, extended chain length raises crystallinity, slows hydrolytic erosion and improves colloidal stability after nanoprecipitation. It moves experimental suitability past short‑term acute in‑vitro assays toward multi‑week cell‑culture workflows and preliminary small‑scale biological validation, without the rigid, long‑persistent characteristics of higher‑MW PCL‑COOH polymers. Formulation researchers adopt this material for building anionic nanoparticle libraries and tuning surface ligand density for intermediate‑duration biological studies.
Key Features: ‑ Intermediate‑length PCL backbone terminated with carboxylic acid group, well‑suited for EDC/NHS‑mediated amide coupling under mixed organic‑aqueous reaction environments ‑ Moderately elevated crystallinity relative to 2 K counterpart; retains favourable solubility in DCM, THF and chloroform while generating dimension‑more‑stable colloidal particles ‑ Intermediate hydrolytic erosion kinetics; maintains particle morphology across multi‑week experimental cycles before gradual mass loss proceeds ‑ Introduces tunable negative surface charge to nanoparticles after assembly, enabling modulation of particle‑cell interaction behaviours ‑ Spectroscopically verified carboxyl end‑group conversion; controlled residual impurity levels fit for cell‑based screening and intermediate‑term biological prototype evaluation
Applications: ‑ Intermediate‑persistence carboxyl‑functionalized micelles and nanoparticles for multi‑week drug‑release profiling and cellular‑interaction investigations ‑ EDC/NHS‑mediated substrate surface decoration for immobilizing amine‑rich peptides in intermediate‑term cell‑phenotype assay setups ‑ Fabrication of amide‑linked polymer‑biomolecule conjugates for mid‑duration biological observation, bridging transient 2 K constructs and higher‑MW long‑residing analogues ‑ Bench‑top formulation screening connecting fast‑degrading low‑MW and mechanically robust medium‑MW PCL‑COOH material series ‑ Exploratory development of anionic polymer‑coated substrates for biomimetic in‑vitro culture platforms
Handling & Storage: Store lyophilized polymer powder at −20 °C under dry inert‑gas conditions. Even though carboxyl end‑groups possess decent chemical stability, long‑term moisture exposure will trigger unintended ester hydrolysis and shift molecular‑weight distribution. Allow sealed sample vials to fully equilibrate inside a desiccator before opening to avoid water condensation contaminating polymer solids. Prepare working solutions with anhydrous organic solvents immediately before experimental use; long‑term storage of dissolved polymer stocks is discouraged. This product is for laboratory‑only research and is not approved for human clinical applications.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.