Phospholipid-nanoparticle constructs, formed by allowing nanoparticles to adsorb to the outer leaflet of liposomes, are found to be stabilized against fusion with one another. Here, through single-particle tracking by epifluorescence microscopy, we explore their use as novel colloidal particles-flexible and hollow colloidal particles that contrast strikingly with colloids of the conventional type. At the single-liposome level, the distribution of diffusion coefficients is quantified. Biomolecular function is addressed through experiments in which we explore the access of receptor to liposome-immobilized ligand, finding that receptor binding persists over a range of nanoparticle surface coverage where liposome fusion and large-scale aggregation is prevented. This opens the door to designing newer and more flexible types of tailor-made materials with desirable functionality.