Nanoparticle having a poly(beta-amino ester) coating. The poly(beta-amino ester) coating includes one or more therapeutic agents that can be delivered by the particle and one or more anchoring groups that couple the polymer to the nanoparticles core surface. In certain embodiments, the poly(beta-amino ester) includes one or more polyalkylene oxide groups. The poly(beta-amino ester) can further include a targeting agent to target the nanoparticle to a site of interest and a diagnostic agent that allows for imaging of the particle. Methods for making and using the nanoparticles are also provided.
