The trick is to choose nucleotides that produce specific reactions in DNA, such as zipping (merging) or unzipping (splitting). As you can estimate how much energy it takes for those actions and the size of the strands, you can customize how quickly the bot moves.

At the moment, the DNA robots have only moved on a nano-sized peg board where it's easy to track where they go. Also, it can take a day for a robot to travel every corner of one of those boards -- efficient, but not very timely. In the long term, though, these genetic automatons could be vital in medicine and other fields. The team envisions nanorobots delivering drugs in your bloodstream when they're triggered by signals or synthesizing therapies in molecular 'factories.' They could even help the environment by sorting molecules in recycling. In short: it's flexible enough that you could eventually have a legion of invisible, microscopic helpers.