Ligand-functionalized CdSe quantum dots and nanorods, and horse spleen ferritin bionanoparticles, were co-assembled at an oil-water interface, then used in polymerization at the interface, effectively cross-linking the assembled mixtures of nanoparticles into robust structures. Both ring-opening metathesis polymerization (ROMP), and imine formation, proved suitable for preparation of the desired ultra-thin films in the form of capsules and sheets. The nanoparticle-based films prepared by ROMP exhibit chemical stability, while those prepared by aldehyde-amine coupling could be disrupted by addition of acid. Characterization of these hybrid nanoparticle-based materials, using transmission electron microscopy (TEM) and fluorescence confocal microscopy, confirmed the presence of both synthetic and naturally derived nanoparticles in the hybrid materials.