PCL(3k)-PEG(1k)-COOH is a linear biodegradable amphiphilic polymer for bioconjugation with protein/peptide or other amine molecule (in the presenc of HATU or EDC activating agent). The hydrophobic block is made of polycaprolactone (PCL) chemically connected to the hydrophilic PEG. The polymer self-assembles in water to form micelles which can be used to encapsulate hydrophobic drugs. Reagent grade, for research purpose.