MIT Engineers Use Artificial Hydrogel Tendons to Supercharge Muscle-Powered Robots
- MM24 News Desk
- 4 days ago
- 3 min read
Engineers at the Massachusetts Institute of Technology have created a biohybrid robot gripper that uses lab-grown muscle paired with artificial tendons. Developed by Professor Ritu Raman and her team, this "muscle-tendon unit" allowed the robot to pinch with three times the speed and 30 times the force of previous muscle-only designs, marking a major leap for the field of biohybrid robotics.
What if robots could heal their own injuries or grow stronger with exercise? This isn't fantasy—it's the promise of biohybrid robotics, a field that combines living muscle tissue with synthetic skeletons to create a new class of machines. But there’s been a persistent problem: these muscle-powered bots are often weak and inefficient. Now, a team from the Massachusetts Institute of Technology (MIT) has found a solution straight from the human body. By adding artificial tendons to the mix, they’ve created muscle robots with a dramatic power boost.
Published in the journal Advanced Science, the research introduces a modular building block for future biohybrid machines. The key innovation is an artificial tendon made from a tough, flexible hydrogel. Lead author Ritu Raman, an assistant professor of mechanical engineering at MIT, explains the concept. “We are introducing artificial tendons as interchangeable connectors between muscle actuators and robotic skeletons,” says Professor Raman. “Such modularity could make it easier to design a wide range of robotic applications.”
The problem they solved is one of mechanical mismatch. Muscle is soft, while robot skeletons are rigid. Attaching one directly to the other often leads to tearing or detachment, and a lot of the muscle's force is wasted. The MIT team’s solution was to design a bridge. They grew a small piece of muscle tissue and attached it at either end to their hydrogel tendons, creating a complete "muscle-tendon unit." This unit was then connected to the fingers of a small robotic gripper.
The results were striking. When the muscle was stimulated to contract, pulling on the tendons, the gripper’s performance skyrocketed. According to the study’s data, the tendon-augmented design pinched three times faster and with 30 times greater force than an identical gripper powered by muscle alone. The system also proved durable, maintaining performance over 7,000 contraction cycles. Critically, the design increased the robot’s power-to-weight ratio by 11 times, meaning far less muscle was needed to do significantly more work.
“You just need a small piece of actuator that’s smartly connected to the skeleton,” Raman explained. “If you attach it to something like a tendon that can resist tearing, it can really transmit its force... and it can move a skeleton that it wouldn’t have been able to move otherwise.”
The hydrogel itself was crucial. The material was provided by co-author and MIT professor Xuanhe Zhao, a pioneer in hydrogel development. The team modeled the system to determine the exact stiffness needed, then etched the gel into thin, cable-like tendons. This careful engineering allowed the soft muscle to efficiently transfer its force to the rigid gripper without damage.
Independent experts see the value. Simone Schürle-Finke, a biomedical engineer at ETH Zürich who was not involved in the study, stated that the work “moves the field toward biohybrid systems that can operate repeatably and eventually function outside the lab.”
The vision for these enhanced biohybrid robots is expansive. Because living muscle can self-heal and grow stronger with use, robots built with these muscle-tendon units could be ideal for long-duration exploration in hazardous environments or as delicate surgical tools inside the human body. The MIT team’s work transforms a biological principle into a versatile engineering component, giving a massive boost to the dream of creating strong, adaptable, and lifelike machines.
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