PCL(4k)-PEG(2k)-BIO is an amphiphile block copolymer which self-assemble in water to form micelles used to encapsulate drugs. The polymer has biotin which can bind strongly to avidin or streptavidin. The polyester polycaprolactone (PLC) is biodegradable via hydrolytic attack on the ester linkages. Reagent grade, for research purpose.