Bacteria navigate microparticle swarms to target

In the 1966 movie Fantastic Voyage, a submarine complete with crew is shrunk in size so that it can navigate through the human body, enabling the crew to perform surgery in the brain. This scenario remains in the realm of science fiction, and transporting a surgical team to a disease site will certainly remain fiction. Nevertheless, tiny submarines that could navigate through the body could be of great benefit: they could deliver drugs precisely to a target location, without causing side effects and stressing the whole organism.