For being fully efficient a targeted delivery system should associate simultaneously multiple functionalities. In this context, the association of several polymeric materials to form composite multifunctional particles can be foreseen. The present work describes the synthesis of different derivates of poly(γ-benzyl-. l-glutamate) and their use for the preparation of nanoparticles exhibiting different properties, including surface hydrophilization by PEG, fluorescence imaging by FITC and target recognition through easy attachment of desired ligands by using the avidin-biotin interaction, after the nanoparticles preparation. Four PBLG derivates were successfully obtained by ring-opening polymerization (ROP) of NCA, using various initiators corresponding to the molecules to be introduced into the copolymers. Further, nanoparticles smaller than 100. nm could be prepared using a nanoprecipitation technique and the presence of the active moieties introduced within the particles as well as their functionality has been checked. Very interestingly, it has been shown that biotin molecules could be efficiently introduced at the surface of the nanoparticles, which (for 75% of the theoretical amount) could be engaged in a complexation with avidin. It is suggested that this strategy offers the possibility to easily decorate these nanoparticles with various recognition ligands for specific targeting applications by using the well known biotin-avidin sandwich technique. © 2009 Elsevier B.V.