Scientists Have Created Tiny Biohybrid Robots Powered by Living Muscle Tissue

Engineering Biological Power: New Biohybrid Actuators Enable Robots to Jump and Swim

A breakthrough in soft robotics has bridged the gap between biological tissue and mechanical engineering, resulting in small-scale robots capable of jumping, grasping, and swimming with unprecedented force. By rethinking the relationship between living skeletal muscle and synthetic structures, researchers at ETH Zurich have overcome the limitations that have long plagued biohybrid systems, where muscle contractions were often too faint to be observed without microscopic assistance.

The study, published in Nature Communications, highlights a fundamental shift in design philosophy. Rather than attaching muscle tissue to pre-existing robot frames, the team—led by Professor Robert Katzschmann of the Soft Robotics Lab—treated the muscle and its support structure as a single, unified system. Co-lead authors Aiste Balciunaite and Mike Y. Michelis utilized computer simulations to co-design the geometry of mouse-derived muscle cells alongside custom hydrogel scaffolds, ensuring the two components work in perfect synergy.

The resulting bioactuators, which measure roughly 1.5 centimeters, exhibit a range of motion up to eleven times greater than previous comparable systems. This increased efficacy stems from an integrated design approach where an algorithm identifies the optimal muscle configuration to maximize the kinetic output of the entire component. Once the computer models were finalized, the researchers utilized a 3D-printing technique known as xolography to produce the hydrogel scaffolds in under one minute per unit.

The mechanical efficiency of these actuators is further enhanced by microscopic architecture. The scaffolds feature intricate grooves that encourage the muscle fibers to align correctly and anchor firmly. This connection minimizes the loss of contractile force, allowing the energy generated by the cells to translate directly into movement. The team observed these small robots leaping five millimeters—one-third of their body length—in a single contraction, and walking at speeds of 6.2 millimeters per second, a velocity that establishes a new benchmark for biohybrid mobility.

Despite these successes, the transition from lab-grown experiments to autonomous, long-term robotics remains complex. Currently, these biohybrid robots require a constant nutrient supply to maintain cell viability. Addressing this, Professor Katzschmann notes that scaling these systems will necessitate the development of synthetic vascular networks to circulate nutrients and oxygen while managing waste removal. Furthermore, the inherent biological variability of living tissue poses a hurdle for the consistency required in standard robotics, prompting the team to focus on better control over laboratory tissue maturation.

This research underscores a growing trend in engineering: viewing living tissue not as a rigid limitation, but as a dynamic material that can be sculpted and integrated into machines. By merging cell biology with computational design and materials science, the team has demonstrated that the future of robotics may lie in harnessing the natural versatility of organisms rather than relying solely on conventional motors.

“We’re just beginning to build robots in a more natural way,” says Katzschmann, noting that as engineers gain the ability to design the shape and function of muscle tissue itself, the possibilities for soft, adaptive robotics continue to expand.