Assembly of Nanoparticles into Hollow Spheres Using Block Copolypeptides

Various modes are being explored for the construction of functional materials out of nanoparticles. Despite these efforts, the assembly of nanoparticles remains challenging with respect to the requirement of multiple component organization on varying dimensions and length scales. We report here a room-temperature, wet chemical-based synthesis route in which silica and gold nanoparticles (∼10 nm) are cooperatively assembled with lysine−cysteine diblock copolypeptides into robust hollow spheres (diameter ∼ microns). The walls of the hollow spheres are composed of two distinct layers of silica and gold nanoparticles, and the hollow center is created without the use of a sacrificial core, emulsion phase, or hollow preformed substrate. Block copolypeptides designed with specific recognition sites for nanoparticles of various compositions provide a versatile approach for the hierarchical organization of nanoparticles into multidimensional composite arrays.