The truly tiny dimensions of nanoscale devices make manufacturing their parts difficult. Instead of fabricating nanometer-sized wiring using conventional electrical engineering, Susan L. Lindquist of the Whitehead Institute for Biomedical Research and her colleagues recruited proteins from yeast to build minuscule circuitry. The yeast Xaccharomyces cerevisiae can self-assemble fibers of varying lengths thanks to a benign prion protein known as NM. The researchers found that the resulting filaments could withstand harsh environments typical of those that might be used for industrial processes. The NM protein strings were tough, durable and heat-resistant; however, they were also insulating--a property unsuitable for circuitry applications. The scientists thus modified the yeast to enable the protein to bond with metal particles. By coating the fibers with silver and gold, they produced metal wires between 80 and 200 nanometers in diameter that could carry a current in much the same way that conventional solid metal wires can.
The authors note that it is easy to envision methods to produce even thinner wires in the future. "With materials like these," Lindquist says, "it should be possible to harness the extraordinary diversity and specificity of protein functions to nanoscale electrical circuitry."