Two spiders are walking along a track – a seemingly ordinary scene, but these are no ordinary spiders. They are molecular robots and they, like the tracks they stride over, are fashioned from DNA. One of them has four legs and marches over its DNA landscape, turning and stopping with no controls from its human creators. The other has four legs and three arms – it walks along a miniature assembly line, picking up three pieces of cargo from loading machines (also made of DNA) and attaching them to itself. All of this is happening at the nanometre scale, far beyond what the naked eye can discern. Welcome to the exciting future of nanotechnology.

The two robots are the stars of