Robots powered by living human muscles are closer to reality thanks to a breakthrough in Japan.
Scientists from the University of Tokyo and Waseda University have developed a biohybrid robotic hand that moves using lab-grown muscle tissue. The researchers just published their findings in Science Robotics.
The biohybrid hand can grasp objects and make a scissor gesture, using living tissue instead of motors. The so-called Multiple Muscle Tissue Actuators (MuMuTa) are tiny bundles of lab-grown muscle fibers that contract like real muscles.
Described as “sushi-like,” they contract when electrical signals are applied, making the fingers move. The researchers stimulated the muscles with electrical signs to build strength.
The team used human cells to grow the muscles in a gel-like substance. The living tissue matured for weeks in a special nutrient-rich fluid. Held together by a 3D-printed robotic skeleton, some of the lab-grown muscles continued working for up to 178 days.
The breakthrough is a major leap for biohybrid robotics, but the team still faced significant challenges.
The muscles got tired after too much use, though they recovered after resting. They worked best at a body temperature of 37° C or 98° F. The muscles also shrank and weakened over time, just like human’s.
The hand’s dexterity is also limited with just 3 degrees of freedom (DoF). Contemporary robotic hands from the likes of Tesla, Sanctuary AI, and Clone Robotics boast dexterity that nearly matches human hands, which have 27 DoF.
Scientists want to build larger, stronger biohybrid limbs like fully functional robotic arms. The technology could revolutionize prosthetics and lead to human-machine hybrids.
The breakthrough illuminates a path toward lifelike machines like in The Terminator franchise, but there’s still a long way to go. Like in the movies, the Japanese robotic hand is powered by bioelectric signals. A lot of advancements are needed to achieve superhuman strength and endurance, not to mention fully autonomous artificial intelligence.
The Terminator’s endoskeleton is covered with living human tissue, which Japanese researchers are also working on.
In 2024, scientists from the University of Tokyo and Harvard showcased a smiling robot face made with living human tissue. They grew the skin in gel, similar to the muscles for the robotic hand.
The skin was secured to a robotic face with tiny ligament-like structures underneath. The mechanism pulled the skin, creating facial expressions. The researchers said the technology could make humanoid robots more lifelike and better for real-life interactions. They plan to add blood vessels to help with the skin live longer.
Waseda and the University of Tokyo are longtime pioneers in humanoid robotics.
In 1973, Waseda University researchers built what’s considered the first full-sized humanoid robot. The WABOT-01 was a technological breakthrough for its time with its vision, speech recognition, and limb movement capabilities.
In 2017, researchers from the University of Tokyo introduced Kengoro, which gained international attention for its hyper-realistic artificial muscle movements and its ability to sweat.
The humanoid robot’s actuators and flexible joints give it a remarkable range of motion. Its unique water-cooling system regulates the robot’s temperature during physical exertion. Water seeps out tiny holes in the metal structure and evaporate, mimicking the way humans sweat. The bio-inspired design prevents Kengoro’s motors and actuators from overheating so it can work for extended periods.
Japan’s unique robotic culture emphasizes bio-inspired design. Shintoism, the country’s indigenous religion, views robots and other machines as beings that can possess a spirit. Robots are viewed more like companions than lifeless tools.
With one of the world’s oldest populations, robots are seen as a solution for worsening labor shortages and elder care. Read more about the fascinating history of Japan’s humanoid robots here.