mPEG(10k)-PCL(3k)-COOH is an amine reactive, via activation with HATU/EDC, amphiphile polymer. The hydrophobic block is made of polycaprolactone (PCL) tethered to a hydrophilic PEG. It can self-assemble in aqueous media to form micelles and be used to prepare nanoparticles for drug encapsulation in nanomedicine/drug delivery. Reagent grade, for research purpose.