The 19th-century chain drive remains popular in bicycles, car engines, and industrial machinery. Now, designers at Sandia National Laboratories in Albuquerque, N.M., have reinvented the component at a microscopic scale. Ed Vernon and his colleagues sculpted thin layers of silicon and silicon dioxide to make a chain that moves gears in a system where the links and teeth are the size of biological cells. Such tiny gadgetry might someday operate shutters for tiny cameras, Vernon notes.
