Source: http://gizmodo.com/5938437/water-powered-nano-rockets-can-safely-explore-the-human-body
The idea of targeting a specific part of the human body with a microscopic rocket carrying a payload of medication has been tossed around for a while. And working nano-sized rockets have already been created, the only problem is that they're powered by chemicals like hydrogen peroxide which will do more harm than good for a patient.
But a team of researchers at the University of California, San Diego, have developed a new kind of micromotor made of an aluminum-gallium alloy that's propelled by hydrogen gas produced by a chemical reaction between the aluminum and water. In pure H2O the rockets—which measure in at a mere 20 micrometers in diameter—can travel as fast as three millimeters per second. But that speed is reduced in denser salt solutions or blood. And while the chemical reaction that propels it is safe for humans, the rocket itself isn't as it dissolves away less than a minute later. So while the Tylenollo 11 isn't ready for launch just yet, this is an important step towards making this technology a viable tool.