PCL(10k)-PEG(2k)-FITC enables self-assembly to form micelles with the arrangment of polycaprolactone (PCL) core and PEG shell. The core regions can serve as hydrophobic drugs reservoir while the shell can provide protection against degradation. Moreover, the PEG shell also allows the "stealth behavior" which is a prerequisite for successful in vivo translation of nanomedicine to achieve long blood circulation and targeted delivery. A green fluorescein is attached on the PEG which can be traced by fluorescence microscopy to investigate biodistribution of the nanoparticles. Reagent grade, for research purpose.