PCL(4k)-PEG(5k)-BIO is a micelle-forming block copolymer with hydrophobic polycaprolactone (PCL) as core and hydrophilic PEG as shell. The polymeric micelles can be used to encapsulate or entrap hydrohobic drugs in the core. The biotin moiety can strongly bind to avidin or streptavidin for protein labeling/purification. Reagent grade, for research purpose.