Tricomponent amphiphilic brush-grafted copolymers of poly(lactic acid)-graft-poly(oligo(ethylene glycol) methacrylate) (PLA-g-POEGMA) were prepared by atom-transfer radical polymerization (ATRP) of oligo(ethylene glycol) methacrylate (OEGMA) macromer using brominated poly(lactic acid) (Br-PLA) as a multisite macroinitiator. Br-PLA was prepared by free radical bromination of poly(lactic acid) (PLA) with N-bromosuccinimide (NBS). The amphiphilic copolymer, PLA-g-POEGMA, self-assembled to form sub-100 nm nanoparticles in aqueous solution. We report the uptake and release of hydrophobic dyes by the nanoparticles in buffer and in the presence of serum proteins and the low toxicity toward mammalian cells.