Robots aren't just taking over the skies—they're taking over our bodies. Or, at least, they could be soon.

A team of researchers from the University of California has recently published a study describing the first successful tests, within a living creature, of nano-robots intended to carry and disperse drugs within the body.

As io9 reported, the acid-fueled micro-machines were implanted in a mouse and found to do just what they were designed to—deliver treatment to an otherwise difficult to access part of the body without causing ill effects. Before this experiment, nano-bots had been tried out only on cell cultures.

So how did this brand of nano-bot go to work? io9 explains:

To make it happen, the researchers constructed polymer tubes coated with zinc. The miniscule machines were a mere 20 micrometers long, which is about the width of a strand of human hair. Once implanted in the gut of a live mouse, the zinc reacted to the acid in the stomach by producing bubbles of hydrogen, which propelled the nanobots into the stomach lining. Once attached, they began to dissolve, thereby delivering their nanoparticle contents within the stomach tissue.

Micro-machines may be our medical future. Recent advancements in nanotechnology indicate that relatively soon the smaller-than-tiny robots might be capable of more than drug delivery; they could help detect diseases and even repair or manipulate damaged cells, potentially providing humans with longer lifespans.

The reality of having a team of mini-robots doing maintenance on your body, though, is still years away. But medical researchers are already incorporating machines into our bodies more initimately than ever before: French doctors have released word that a man who received an artificial heart in August has just returned home to live a normal life, signaling that the medical community is one step closer to commercializing permanent artificial replacement hearts.