PLGA(5k)-PEG(2k)-RhB is a block amphiphilic polymer. In water, the hydrophilic PEG is shielding the hydrophobic poly(lactide-co-glycolide) (PLGA) from the water. Therefore, hdyrophobic drugs can be encapsulated in the core of the nanoparticles which then can be traced easily using microscopy technique. Reagent grade, for research purpose.