PCL(3k)-PEG(1k)-RhB is commonly used 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 red fluorescent probe can be used for cell/nanoparticles staining and can be easily traced by fluorescence microscopy. Reagent grade, for research purpose.