ETH Zürich creates jumping robots on mouse muscle tissue

According to the authors, the amplitude of movement of such devices, approximately 1.5 centimeters in length, can be up to 11 times higher than that of previous systems with a comparable volume of muscle tissue. With one contraction, the actuator lifts off the bottom of a cup by about 5 millimeters, or almost a third of its own length. The walking variant moves at a speed of 6.2 millimeters per second. In terms of body length, this is faster than all previously described walking biohybrid robots.

The leading authors of the study are Aiste Balcytite and Mike J. Mitchell. What was new in their work was that the muscle and soft water-saturated hydrogel frame were designed simultaneously, as a single system. A computer algorithm selected where and how much tissue to place and what properties to endow the frame with, so that contraction would give the greatest movement of the structure. Then the frames were printed with light using the method of xolography, with one taking about a minute.

The researchers note that such strong movements require a strong continuous connection between the tissue and the frame. Thin grooves on its surface hold the muscle and determine the direction of the fibers. So far, the robots only work in a nutrient medium that keeps the tissue alive. The researchers are still far from creating devices that can operate for a long time.