PCL(2k)-PEG(2k)-Thiol is widely used amphiphilic polymer to prepare drug loaded nanoparticles for drug delivery or scaffold in tissue engineering. It is an amphiphilic block polymer with a PEG hydrophilic attached to a hydrophobic polycaprolactone (PCL) block. The terminal thiol can react with maleimide to form a thioether bond. Reagent grade, for research purpose.