PCL(2k)-PEG(2k)-BIO is a polymer with both hydrophobic (polycaprolactone/PCL) and hydrophilic (PEG) blocks. The self-assembly of the polymer in water occurs with PCL being shielded at the core by PEG shell. The hydrophobic core can be used to encapsulate lipophilic drugs while the PEG shell offers protection against (enzymatic/hydrolysis) degradation in drug delivery/nanomedicine. The biotin can strongly bind to avidin/streptavidin. Reagent grade, for research purpose.