Researchers at Penn State University and Weinberg Medical Physics in Maryland have developed microscopic metallic motors known as nano-motors and injected them into a human body to destroy cancerous cells.

Professor Tom Mallouk said: “Our first-generation nano-motors ran on toxic fuels, which was a serious limitation.” Once the researchers discovered that they could be powered by ultrasonic waves, the way was cleared for using them in living cells.

In addition to using sound waves to spin them, the researchers used magnetic fields to steer them around inside the cells. They also discovered that individual motors could be controlled independently of the others, making them able to do very precise work. “If you want these motors to seek out and destroy cancer cells, it is better to have them move independently. You don’t want a whole mass of them going in one direction. They could also perform intra-cellular surgery and deliver drugs to living tissues.”