Protein polymers derived from elastin-mimetic peptide sequences can be synthesized with near-absolute control of macromolecular architecture using genetic engineering techniques. Elastin-mimetic diblock and triblock copolymers have been prepared using this approach in which the individual elastin blocks display different phase behavior in aqueous solution. The selective collapse of the more hydrophobic blocks above the lower critical solution temperature was employed to drive the thermo-reversible self-assembly of elastin-mimetic diblock and triblock copolymer into protein-based nanoparticles and nano-textured hydrogels, respectively. These materials display considerable promise as biomaterials for applications in drug delivery and soft tissue augmentation.