By building on tiny organisms, researchers at the U.S. Department of Energy's Argonne National Laboratory are hoping to create a new generation of tiny machines for electronic and photonic devices.
Using a heat tolerant protein from Sulfolobus shibatae, a bacterium that lives in geothermal hot-springs, they are able to form ring-shaped cells just 10 to 20 nanometers across. Called chaperonins each cell is analogous to cells in arrays produced by lithographic techniques for computer chips, but even the best modern techniques are limited to around 100nm. These biological based arrays of nanoparticles could have future applications in computer memories, sensors or logic devices.
They arrays are formed by applying the chaperonins to a substrate of silicon where they self-assemble into a repeating hexagonal pattern. A slurry of gold nanoparticles and a semiconducting material, cadmium selenide-zinc sulphide, is then added. The materials adhere only to active sites around the hole in each protein ring resulting in a precise, regular array of nanoparticles.