Smallest Engine In World Is Made Of Gold Balls

Scientists at Cambridge University have created the smallest engine in the world.

The tiny engine measures just a few billionths of a metre and could one day be used to power nanomachines inside the body to fight disease.

The engine prototype is made from tiny gold particles stuck together using a temperature-responsive polymer in the form of a gel.

A laser is then used to pull the particles together, and turned off to push them apart.

Cambridge University's Dr Tao Ding said: "It's like an explosion. We have hundreds of gold balls flying apart in a millionth of a second when water molecules inflate the polymers around them."

The team behind the prototype says the devices are cheap to manufacture, and energy efficient.

Research leader Professor Jeremy Baumberg called the engines actuating nano-transducers, or ANTs.

He said: "Like real ants, they produce large forces for their weight."

Nanomachines - tiny devices which could be put to work inside the body - have been a dream of scientists for decades.

But finding a way to power them has been a stumbling block - until now.

The team is now working with the university's commercialisation arm to try to find bio-applications for the technology.