Representing the entry‑point medium‑molecular‑weight member of the PCL‑Maleimide family, this 5 kDa material brings noticeable chain entanglement and improved colloidal stability to thiol‑reactive polyester platforms. The terminal maleimide group delivers robust Michael‑addition reactivity toward cysteine‑rich biomolecules, performing reliably even when nanoparticle pre‑formulation steps introduce partial aqueous exposure. Compared to 3 K and 2 K counterparts, extended polymer chains raise crystallinity and decelerate hydrolytic breakdown, shifting experimental suitability away from short‑term acute assays toward multi‑week in vitro studies and early‑stage subcutaneous in‑vivo work. Formulation scientists favour this grade when building ligand‑functionalized particulate systems that need to retain physical integrity throughout biological testing, without the extreme slow degradation profile seen in 10 K and higher PCL‑Maleimide polymers.
Key Features: ‑ Medium‑length poly(ε‑caprolactone chain capped with maleimide; engineered to tolerate brief aqueous exposure during nanoparticle preparation without rapid functional‑group loss ‑ Noticeable chain entanglement improves particle dimensional stability post‑nanoprecipitation; resists premature disassembly relative to 2 K / 3 K low‑MW analogues ‑ Moderate hydrolytic erosion behaviour; material maintains structural integrity across multi‑week experimental timelines before gradual mass loss occurs ‑ Maintains thiol‑specific reactivity within pH 6.0‑7.4 operational range; compatible with protein fragments, cysteine‑modified aptamers and synthetic thiol‑containing targeting ligands ‑ NMR‑validated maleimide end‑group conversion; low residual catalyst and monomer content appropriate for cell‑level investigations and preliminary subcutaneous animal model trials
Applications: ‑ Ligand‑conjugated PCL nanoparticles and micelles maintaining structural integrity for multi‑week drug release and cellular interaction investigations ‑ Thiol‑mediated surface modification of electrospun thin‑film scaffolds for subcutaneous tissue‑culture mimic models ‑ Fabrication of polymer‑antibody fragment conjugates for preliminary passive‑targeting prototype evaluation in small‑animal subcutaneous settings ‑ Formulation optimisation workflows bridging fast‑eroding low‑MW PCL‑Maleimide and mechanically robust high‑MW polymer grades ‑ Bench‑scale screening of surface‑functionalized particulate carriers prior to advancing toward higher‑molecular‑weight implant‑oriented formulations
Handling & Storage: Keep solid polymer stored at −20 °C under dry inert gas atmosphere and protected from light, as maleimide functionalities degrade via hydrolytic ring‑opening upon contact with moisture. Place sealed vials inside a desiccator and allow full thermal equilibration to room temperature before opening to prevent condensation‑driven contamination. Prepare working stock solutions right before experimentation using anhydrous, thiol‑free organic solvents; avoid long‑term storage of dissolved polymer solutions. For laboratory‑only research deployment; not authorised for human clinical applications.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.