Robots capable of jumping, swimming, walking or grasping objects can now be powered by real muscles grown in the laboratory.
These machines are called biohybrid robots because they combine manufactured components with living tissues. Here, the muscle acts as the engine. When it contracts, it pulls on a flexible support and causes movement. The concept is not new, but achieving large movements with a small amount of muscle remained difficult.
Pixabay illustration
Researchers at ETH Zurich have changed the way these systems are designed. Instead of working separately on the muscle and then on its support, they studied both together. Computer simulations made it possible to test many shapes before manufacturing them, in order to identify those that best converted muscle contraction into movement.
Specifically, the researchers combined cultured skeletal muscle with hydrogel supports. This highly water-rich material is flexible enough to accommodate contraction. Tiny grooves also guide the organization of the muscle tissue. The continuous contact between the two parts then helps transmit the force produced by the cells to the rest of the device.
The improvement is significant: the new devices achieve up to eleven times the range of motion of earlier models using a comparable volume of muscle. This improvement is based on the shape of the system and on the way the muscle and its support work together.
Figure from the study showing movements produced by muscle bioactuators integrated into soft robotic devices.
Source: Balciunaite et al., Nature Communications, 2026 — CC BY 4.0
The researchers then integrated these biological motors into several small machines. Some prototypes jump, while others swim by contracting several times per second. Another configuration can walk and even navigate around an obstacle. A clamp-shaped device can also close to grasp an object.
To understand the value of this approach, it is useful to consider what distinguishes a muscle from a conventional motor. Living tissue can organize itself and adapt as it grows. It also has a capacity for repair that an ordinary mechanical part does not possess. In return, it must remain alive, and its behavior depends on biological conditions that are difficult to reproduce outside the laboratory.
The method also makes it possible to assemble multiple muscle units. The researchers thus produced structures containing several moving elements, offering a path toward building larger biohybrid machines or devices capable of more complex movements. Future work will need to determine how far this architecture can be scaled up while preserving fast, well-controlled contractions.