The idea of ​​smuggling tiny robots into the body so that they can target pathological cells is not new. Numerous systems have already been tested in laboratory experiments. Researchers at Purdue University in the USA have now succeeded for the first time in a test in a living organism.

Difficult localization As reported by the research team led by David J. Cappelleri in the current issue of Micromachines, the 800 × 400 × 100 Micrometer-sized robot in the intestine of a Mouse introduced. As with a normal colonoscopy, the bowel had previously been emptied, filled with saline and also immobilized with the help of atropine. The robot, doped with neodymium-iron-boron, was set in motion by a rotating magnetic field so that it turned around its transverse axis and thus moved back and forth like a spoked wheel.

(Source: Purdue University) A special challenge when using microrobots in living The researchers write that bodies are their localization. They are too small for their own energy supply or data processing and therefore cannot transmit any data or determine their position themselves. That must be done from the outside. However, some visualization methods such as X-rays are very complex, others such as magnetic resonance tomography do not get along with the magnetic actuation of the robots. High-frequency ultrasound is more suitable for clinical use. With this, Cappelleri and his team could actually watch and film the movements of the robot in the mouse intestine.

Future helpers with colonoscopies The measured speed of the robot was 2 mm / s. In a comparison test in a test tube with one percent carboxymethyl cellulose solution, the viscosity of which is about 4500 – times as high as that of saline solution, he only managed 0.2 mm / s. It got stuck in the even more viscous ultrasound gel.

The forces measured during movement in the intestine were so low that there was no risk of damage to the intestinal walls