These Nanobots Can Swim Around a Wound and Kill Bacteria

There's always been something seductive about a nanobot. Comic books and movies implore you to imagine these things, thousands of times thinner than a human hair and able to cruise around a body and repair a bone or heal an illness. Their scale is unfathomably finite. Their possibilities, sci-fi will have you believe, wildly infinite. While that incongruity makes it perfect for the denizens of a writers' room figuring out how to kill James Bond, it's also a sort of curse.