mPEG(10k)-PCL(5k)-COOH is a block amphiphilic copolymer. Upon dispersion in water, the polymer self-assembles to form micelles with polycaprolactone (PCL) core and PEG shell. The core can be used as reservoir for hydrophobic drugs while the shell can provide protection from degradation (enzymatic/hydrolysis). The acid (COOH) is reactive with amino molecule in the presence of activator, such as HATU/EDC. Reagent grade, for research purpose.