Tel Aviv University micro-robots learn to climb obstacles and ferry live bacteria

Engineers at Tel Aviv University have found a way to steer microscopic robots across more than one surface, letting them climb over obstacles and carry living cargo. The work, led by doctoral student Ido Rachbuch, Dr Sinwook Park and Professor Gilad Yossifon of the university's schools of mechanical and biomedical engineering, was published in Nature Communications and described in English by Ynetnews on 26 July 2026.

Micro-robots of this kind measure roughly 10 to 30 microns, about the size of a biological cell, far too small to carry motors or batteries. They are driven and steered from outside by magnetic, electric or other fields, and most designs have been confined to rolling along a single flat surface. The Tel Aviv team used Janus particles, tiny spheres whose two halves have different properties: one hemisphere is coated with an electrically conductive material and another carries a magnetic layer. The magnetic field controls the particle's orientation, rolling and lifting, while the electric field supplies propulsion, makes the robot stick to a surface and lets it grab and release microscopic loads on demand.

With the two fields working together, the researchers achieved what they call 2.5-dimensional navigation. Under real-time feedback control, the robots rolled along the ceiling of a chamber, dropped back to the floor, climbed onto raised surfaces and crossed microscopic walls along planned paths. They also picked up plastic particles and live E. coli bacteria, carried them over barriers and released them at chosen spots, and the bacteria survived the trip.

Yossifon said the approach shows that even simple micro-robots can perform tasks that once required far more complex machines. The team sees uses in lab-on-a-chip devices, for moving and sensing individual cells and for assembling tiny structures.