Biohybrid Hand Demonstrates Next-Level Muscle-Controlled Movement

In a major step for biohybrid robotics, researchers in Japan have successfully revealed a hand powered by lab-grown muscle tissues.

• Multiple muscle tissue actuators (MuMuTAs) enable stronger, larger-scale movement
• Scissor gesture and pipette handling showcase dexterity
• Potential applications range from advanced prosthetics to lab automation

A team from the University of Tokyo and Waseda University has constructed a biohybrid hand capable of performing intricate gestures and handling small objects. By combining 3D-printed components with strings of human muscle tissue, known as multiple muscle tissue actuators (MuMuTAs), they have achieved a promising new level of functionality and flexibility.

Unlike smaller biohybrid devices, which typically measure around 1 cm, this new hand is an 18 cm construct that can move each finger independently. According to the press release, “Rock, paper, scissors” might never be the same again: “But choose paper and you are going to lose to this robot hand, which has mastered the art of the scissor gesture.” While this may sound playful, the underlying work is serious, as it points to the possibility of biohybrid limbs that function much like their real-life counterparts.

MuMuTAs and Controlled Movement

The researchers overcame a long-standing challenge in biohybrid robotics: generating sufficient contractile force to move larger structures. “Our key achievement was developing the MuMuTAs,” explained Professor Shoji Takeuchi from the University of Tokyo. “These are thin strands of muscle tissue grown in a culture medium and then rolled up into a bundle like a sushi roll to make each tendon.” By bundling multiple thin muscle tissues together, the team circumvented the problem of necrosis, which occurs when nutrients fail to reach the core of thick muscle.

To demonstrate the hand’s abilities, the team used electrical stimulation to flex the thumb, ring finger and little finger. This produced the scissor gesture, and also allowed the hand to grip and move the tip of a pipette. Each finger can be moved separately or in combination, further underscoring the versatility of the technique. The muscle-driven movement, however, requires the hand to remain submerged in liquid so that the ties connecting the muscle to the 3D-printed skeleton can move freely without friction.

As with any living muscle, these engineered tissues fatigue over time. Takeuchi noted, “While not entirely surprising, it was interesting that the contractile force of the tissues decreased and showed signs of fatigue after 10 minutes of electrical stimulation, yet recovered within just one hour of rest.” Such behaviour is reminiscent of natural muscle responses, highlighting the potential for biohybrid limbs to behave in ways closely aligned with real biology.

Prospects for Lab Automation and Prosthetics

While the immediate result is a lab-based prototype, the long-term applications could be substantial. In particular, researchers foresee the use of MuMuTAs in advanced prosthetic limbs, where an ability to mimic natural muscle function may enable more precise and responsive control. Additionally, the technology could serve as a platform for drug testing, allowing scientists to analyse how certain compounds interact with living muscle tissue in a controlled environment.

Beyond its direct role in biomedical devices, this innovation could also transform lab automation. Automated systems equipped with biohybrid components might better handle delicate tasks such as pipetting, transferring samples or performing complex manipulations that currently require human dexterity. If scaled further, these muscle-based actuators could offer a more biological approach to robotic research, providing insights into how best to integrate living tissues with synthetic structures.

Despite these promising achievements, the hand remains limited by its need to float in liquid and by its lack of a mechanism to revert fingers to a neutral position under active control. However, Takeuchi is optimistic that adding elastics or additional MuMuTAs could address these issues. “A major goal of biohybrid robotics is to mimic biological systems, which necessitates scaling up their size. Our development of the MuMuTAs is an important milestone for achieving this,” he said. “The field of biohybrid robotics is still in its infancy… Once these basic hurdles are addressed, this technology could be used in advanced prosthetics, and could also serve as a tool for understanding how muscle tissues function in biological systems, to test surgical procedures or drugs targeting muscle tissues.”