Tiny “robots” that could perhaps someday help doctors examine organs, deliver drugs directly, or even perform microsurgery. But first researchers need to find reliable and accurate ways to control microscopic devices, which of course have little room for onboard power, sensors or propulsion.

Scientists have previously used methods including magnetic and electrostatic forces, and attaching live bacteria. In the latest issue of the International Journal of Robotics Research, researchers from ETH Zurich demonstrate particularly deft control of a microbot, dubbed MagMite.

MagMite, pictured above, is 300 micrometers by 300 micrometers (with a thickness of 70 micrometers). It consists of two magnetized components, connected by a tiny spring. In the presence of a magnetic field, the two pieces try to bend toward each other, storing that tension in the connecting spring. By turning the magnetic field on and off very quickly, the researchers can use the loaded spring to propel the microbot forward, and by changing the direction of the magnetic field the microbot will turn.

In the video below, MagMite wins the 2009 Nanogram RoboCup competition by autonomously pushing a tiny particle into a target while avoiding obstacles. Frutiger says the control method could also be useful in a lab setting for manipulating tiny biological matter. Currently, the MagMite only works in two dimensions.