Most nanotechnology is about the properties of materials with a given structure at a nano-scale. The results of the latest research at Tufts University has a far more practical application. It is the first electrically-driven single-molecule engine.
The engine needs to run at a very low temperature (5 Kelvin) to be managable, but it is a significant step forward in producing nano-scale controllable structures. As well as providing motive power, the engine also has the potential to be inverted to use the spin of the molecule to generate power at a nano-scale.
Read more at Tufts University here: http://now.tufts.edu/articles/really-little-engine-could