Imagine tiny robots crawling inside of you, diagnosing problems and imaging your body. Israel's Technion has developed just the tool: the ViRob, a robot with a diameter of 1mm. It's controlled by external magnetic fields, and it crawls through veins.
The minuscule robot is powered and directed by external magnetic fields. That means no wires or batteries. The robot uses its tiny arms to grip walls and propel itself forward. Once it's in, it can operate essentially autonomously, relentlessly trolling through the desired areas of a human body.
The ViRob can crawl at 9mm per second through openings no wider than 3mm. To put this in perspective, the average ear canal is about 7mm in diameter, while veins can be up to 6mm in diameter. The ViRob would have no problem with either of those.
The Technion is still working on actual applications, but they postulate that the ViRob will be useful in microsurgery and imaging. It's also useful as a frightening glimpse at future nano-tech gone wild.