Until now, there has been no suitable method for this. Scientists from the German Cancer Research Center (DKFZ) have now described a signaling method based on an oscillating magnet that can significantly improve such medical applications.

The study is published in the journal npj Robotics.

What until recently sounded like science fiction is now well advanced in development: Nanorobots that move independently through the body are expected to transport drugs, take measurements in tissue or perform surgical procedures. Magnetically driven nanorobots that navigate through the muscle, through the vitreous body of the eye or through the blood vessel system have already been developed.

However, there is a lack of sophisticated systems to track and control the activities of the robots deep inside the body in real time. Traditional imaging techniques are only suitable to a limited extent. Magnetic resonance imaging (MRI) is limited in temporal resolution, computer tomography (CT) is associated with radiation exposure and the strong scattering of sound waves limits the local resolution of ultrasound.

A team led by Tian Qiu from the DKFZ, Dresden site, has now invented a new method to solve this problem. The tiny device they have developed is based on a magnetic oscillator (i.e., a mechanically oscillating magnet located in a millimeter-sized housing). An external magnetic field can excite the magnet to vibrate mechanically.