Even better, the team can control exactly where the nanobots finish up -- at a particular organ, say -- by modulating the field. Though inserting tiny bits of metal into your body sounds weird, scientists believe nanobots could reduce the need for invasive surgery, speed recovery and lower the risk of complications. The new research removes the need for a (tiny) motor inside the nanobots, freeing up space for drugs that can target, say, cancer cells. It also makes the bots fairly easy to build and tune for different applications. There's still a lot of work to be done before it ever gets to trial, starting with subjects willing to do let robots ply their bloodstream.