PCL(3k)-PEG(1k)-BIO is a self-assembling biotinylation copolymer which has strong binding to avidin or streptavidin. The biotinylation polymer can be used for non-radioactive labeling and purification of proteins and other target molecules. The polymer can form micelles in water with core and shell made of polycaprolactone (PCL) and PEG, respectively. It can be used to encapsulate hydrophobic drugs. Reagent grade, for research purpose.