Breakthrough in Biohybrid Robotics: Japanese Researchers Develop Largest Ever Muscle-Powered Hand

A research team from the University of Tokyo and Waseda University has developed the largest-ever “biohybrid” robotic hand incorporating cultivated human tissue. The team, led by Xinzhu Ren and Shoji Takeuchi from the University of Tokyo’s Graduate School of Information Science and Technology, along with Yuya Morimoto from Waseda University’s Faculty of Science and Engineering, engineered a robotic hand powered by living muscle tissue. Measuring 18 centimetres in length and featuring a 6-centimeter palm—comparable to a newborn’s hand—the five-fingered device is capable of independent motion. Their findings were published in Science Robotics.

The innovation centres on a newly designed multiple muscle tissue actuator, which uses bundled strands of cultured human tissue in a "sushi roll" formation to form a larger muscle. This structure ensures proper nutrient distribution, preventing tissue necrosis (usually localized death of living tissue) and maintaining muscle fibre alignment. Conventional biohybrid actuators have typically been limited to about 1 centimetre in thickness and capable of activating only a single joint. In contrast, this new actuator enables greater contraction distances, force, and speed.

The biohybrid hand operates within a culture solution tank, where artificial muscles contract upon electrical stimulation, pulling fine wires to bend the fingers. It also mimics human muscle fatigue, weakening after about 10 minutes of use but recovering in an hour by absorbing sugar from the solution. The system successfully demonstrated precise finger movements, including imitating gestures and manipulating small objects like pipette tips. While it cannot yet grasp heavier objects, this breakthrough marks significant progress in biohybrid robotics.

Beyond robotics, this development could revolutionize muscle-driven prosthetics and provide new models for drug testing and surgical research. "A major goal of biohybrid robotics is to mimic biological systems. Our development is an important milestone for achieving this," said Takeuchi. He also emphasized that while biohybrid robotics is still in its early stages, overcoming foundational challenges could lead to applications in advanced prosthetics and medical research.