One of the smallest motors built so far consists of only 78 atoms, but four years of work was involved in its construction.
T. Ross Kelly, a Boston College professor of chemistry, thought it would be "neat" to fabricate a molecule that operated like a motor. He published a report about his and his Boston College colleagues' rather successful results in the September 9, 1999 issue of Nature.
Similar things exist in nature, such as corkscrew flagella on mobile bacteria, but they are little understood. Kelly, in his creation, offers just one scenario among many for such biological machines. His molecular motor is in need of improved configuration though, since its "paddle water wheel" jams after rotating only 120 degrees. According to Trinity College chemist Anthony Davis of Ireland, "It's really just a proof of principle."
Yet Kelly is sure that continuous rotation is possible and will be achieved.
In the same issue of Nature, a 58-atom molecule, which spins continually when light is applied to it, is described by Dutch and Japanese scientists. Their motor is a very slow one, taking several minutes to revolve. And, at present, 140 degrees Fahrenheit is the minimum heat requirement for its operation. Viability at room temperature is, of course, sought.
There are potential computing and medical applications for further-developed molecular motors, but they are likely decades away from fruition.
Source: ABCNEWS.com, 9/9/99