We explore the access of receptor (streptavidin) to liposome-immobilized ligand (biotin) in cases where the liposomes are stabilized against fusion by allowing nanoparticles to adsorb. It is found that receptor binding persists over that range of nanoparticle surface coverage where liposome fusion and large-scale aggregation are prevented. This indicates that liposome outer surfaces, in the presence of stabilizers, remain biofunctionalizable, and may have bearing on explaining the long circulation time of stabilized liposomes as drug delivery vehicles.