The world’s smallest engine has been created in a lab at Cambridge University. It is fuelled by lasers and gold and is so tiny it could power the nanobots scientists hope to inject into our bodies in future to keep us healthy. The engine, which is powered by laser light, is aptly named the ANT (standing for actuating nano-transducer) and takes cues from its insect counterpart in the sense that it is small and mighty. The microscopic ANT engine, which cannot be seen by the human eye, is believed to be up to a hundred times more powerful than any other engine known to man if you take its force to weight ratio into account.

The prototype device, known as an actuating nano-transducer or Ant, combines microscopic gold balls with a special polymer gel. It generates a propulsive force on a microscopic scale that is a hundred times greater per unit weight than any known motor or muscle.

The prototype Ant uses laser light to control the system’s temperature but other mechanisms could be used instead. The transition point could also be adjusted, for example to set the energy release point close to 37C — the human body’s normal temperature. 

The Ant might drive a nanobot through a series of piston strokes, rather like a car engine but on a scale many billions of times smaller.