THE smallest motor ever built has been chugging away merrily in a German lab. Its mechanism consists of a single molecule, and it’s powered by nothing more than a beam of light. The team who built it think that such photon-powered motors could be the next little thing in nanotechnology.
Hermann Gaub, a biophysicist at the University of Munich, and his colleagues built their nanomotor from a synthetic azobenzene polymer. This molecule contains pairs of nitrogen atoms with a benzene ring attached on either side. The nitrogen “bridge” between the rings is kinked, but when exposed to a particular wavelength…
