Scientists at the University of California, San Diego, have created what they claim is the first self-propelling, hydrogen-bubble-powered "microrocket" requiring no external source of fuel. In the most acidic solutions, these micromotors can reach speeds of 100 body lengths per second. It's claimed that the breakthrough could pave the way (or rather line the esophagus) towards stomach-going nanomotors which could provide imaging or precisely targeted drug treatment. In addition to self-propulsion, the gut-rockets can be steered, and made to collect and release a payload.
Read the full article: Hold onto your stomach - scientists create bubble-propelled gut-rocket