Poly(L-lactide)-b-poly(ethylene glycol)-azide is a functional amphiphilic block copolymer with azide group at the end of PEG. PLA-PEG-N3 is used to prepare micelles or nanoparticles with azide on the micelle surface for bioconjugation via click chemistry. Hydrophobic drugs is encapsulated in the PLA core for targeted drug delivery.