NEARLY BOILING, acidic hot springs could lead to the creation of electronic components that are 10 to 100 times smaller than today’s smallest parts.
While exploring extreme environments similar to those that might exist on other planets, scientists at the NASA Ames Research Center investigated natural hot springs. While experimenting with microbes that live in the springs, researchers discovered that modified proteins taken from the organisms could be used to grow meshlike “nanostructures.”
By manipulating the DNA in the Sulfolobus shibatae protein, the researchers were able to create proteins that self-assemble into a tiny, two-dimensional lattice capable of capturing metal and semiconductor material particles at specific locations.
Creating large quantities of the modified protein is relatively easy. The researchers clone the gene coding for the protein into rapidly multiplying E. coli bacteria and then brew the mixture inside a vat. The high temperature process doesn’t affect the protein?which is accustomed to living in a hellish environment?yet it safely destroys nearly all the proteins from the nasty E. coli bug.
The Sulfolobus protein self-assembles into rings that are about 5,000 times thinner than a human hair. These then associate into a honeycomblike lattice that is applied to a silicon wafer substrate and then blanketed with a gold or semiconductor slurry of particles. “The particles that stick to the structure are ’quantum dots’ that are about one to 10 nanometers across,” says Andrew McMillan, the project’s coinvestigator. Current computer chips contain features that are approximately 130 nanometers apart.
“With further refinement, the nanostructures could someday serve as computer memory, a sensor or a logic device,” says McMillan. First, however, researchers must find a way to develop large numbers of protein-based circuits at a competitive price. But the raw material is cheap and the size benefits substantial, so that shouldn’t be a big problem. “The obstacles seem surmountable,” says Jonathan Trent, the research project’s principal investigator.