Test-drive for nanocopters

The first microscopic "helicopters", which could one day carry out medical tasks inside the body, have been built and test-driven by scientists at Cornell University. The devices are no bigger than a virus particle. They consist of metal propellers and a biological component attached to a metal post. The biological component converts the body's biochemical fuel, ATP, into energy. This is used to turn the propellers at a rate of eight rotations per second. In tests the nano-helicopters' propellers for up to 2 1/2 hours. This is an important first step towards producing miniature machines capable of functioning inside living cells. But at this stage the technology is still very inefficient. Only five of the first 400 biomotors worked properly, and it still has to be proved that the machines can function inside a living cell.