For more than two decades, nonscientists and engineers have made molecular-scale motor, switches, propellers, ratchets, and even the "nanocar" above that rolls when its metal "road" is heated. But what can we actually do with these things? The journal Nature looks at today's efforts to develop useful applications for molecular machines, from drug delivery systems inside the body to a new kind of high-density molecular memory for computers.
"We've made 50 or 60 different motors," says Ben Feringa, a chemist at the University of Groningen in the Netherlands. "I'm less interested in making another motor than actually using it."
That message was heard clearly in June, when one of the influential US Gordon conferences focused for the first time on molecular machines and their potential applications, a clear sign that the field has come of age, says the meeting's organizer, chemist Rafal Klajn of the Weizmann Institute of Science in Rehovot, Israel. "In 15 years' time," says Leigh, "I think they will be seen as a core part of chemistry and materials design."
Getting there will not be easy. Researchers must learn how to make billions of molecular machines work in concert to produce measurable macroscopic effects such as changing the shape of a material so that it acts as an artificial muscle. They must also make the machines easier to control, and ensure that they can carry out countless operations without breaking.