The fusion of biology and robotics has taken a significant leap forward by creating an artificial hand powered by lab-grown muscle tissue. Researchers from the University of Tokyo and Waseda University have successfully integrated biological muscle fibers with flexible mechanical joints, allowing the hand to grip and make gestures.
While soft robotics and advanced prosthetics have made great strides, true biohybrid systems where living tissue is seamlessly combined with mechanical components are still relatively rare. Some previous experiments have included an artificial fish powered by human heart cells and a robot that used a locust’s ear to detect sound. However, practical applications of this technology have remained elusive until now.
In their latest breakthrough, the Japanese research team cultivated muscle fibers in a lab and bundled them into Multiple Muscle Tissue Actuators (MuMuTAs). These MuMuTAs were then attached to a 3D-printed artificial hand, measuring about 18 cm (7 inches) in length. “Our key achievement was developing the MuMuTAs,” stated Shoji Takeuchi from the University of Tokyo, co-author of the study published in Science Robotics. “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.”
Once integrated into the robotic hand, the MuMuTAs were stimulated using electrical currents, successfully enabling the hand to form a scissor gesture and manipulate objects like a pipette. Interestingly, researchers observed that the hand, much like a biological limb, experienced fatigue after extended use. “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,” Takeuchi explained. This finding further reinforces the similarity between lab-grown muscle tissue and real human muscles.
Despite its success, the project remains a proof of concept rather than a fully functional device. For now, the hand needs to be suspended in liquid to reduce friction and allow movement. The researchers suggest that adding elastic components or orienting additional MuMuTAs in the opposite direction could provide better control and stability in future versions.
Still, the breakthrough represents a major step forward for biohybrid robotics. Previously, biohybrid models were limited to centimeter-scale designs, but this 18 cm-long artificial hand demonstrates that scalability is possible.
“A major goal of biohybrid robotics is to mimic biological systems, which necessitates scaling up their size,” Takeuchi remarked.
“Our development of the MuMuTAs is an important milestone for achieving this.”