Muscle Tissue and Mechanics Combine in Biohybrid Hand Innovation

Researchers have made significant progress in creating an artificial hand that can grip and perform gestures by integrating lab-grown muscle tissue with flexible mechanical joints. This breakthrough opens up new possibilities for robotics, with numerous potential applications.

Challenges in Merging Human Tissue with Machines

While we’ve seen a variety of soft robots and innovative mechanical prosthetics, few inventions have merged human tissue with machines in such a direct way. This is largely due to the fact that biohybrid science is still in its early stages. Although a few notable examples exist, such as a fish powered by human heart cells and a robot using a locust’s ear to hear, the technology’s practical applications have remained limited.

However, researchers from the University of Tokyo and Waseda University in Japan have now demonstrated a significant advancement in this field.

To build their biohybrid hand, the team initially grew muscle fibers in the lab. Since the tissues alone wouldn’t provide sufficient strength without risking damage, the researchers bundled them into what they called multiple tissue actuators, or MuMuTAs. The researchers then attached these muscle bundles to a 3D-printed plastic hand with movable joints, measuring about 18 cm (7 inches) long.

“Our key breakthrough was developing the MuMuTAs,” said 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, rolled up like a sushi roll to form each tendon. Developing the MuMuTAs allowed us to solve our major challenge, which was ensuring enough contractile force and muscle length to operate the hand’s large structure.”

Key Breakthrough: Creating MuMuTAs

Once the researchers connected the MuMuTAs to the artificial hand, they stimulated them with electrical currents. As a result, they successfully got the hand to perform a scissor gesture and manipulate a pipette’s tip.

One of the most intriguing findings was that the biohybrid hand, similar to a human hand, showed signs of “fatigue.” The force exerted by the tissue decreased with use, much like human muscles do.

“It wasn’t surprising that the contractile force weakened after 10 minutes of stimulation, but it was fascinating that the tissue recovered in just an hour of rest,” Takeuchi remarked. “Seeing this recovery, similar to how living tissues behave, was an incredible and exciting result.”

Next Steps: Addressing Challenges for Practical Use

Though the hand serves more as a proof of concept than a fully functional device, Takeuchi and his team acknowledge that the technology still has a long way to go. For example, they had to suspend the entire hand in liquid to reduce friction and allow the joints to move freely. The suspension also helped return the hand segments to a neutral position after being flexed by the muscle tissue. However, the team believes that adding elastic material or more MuMuTAs oriented oppositely could address this challenge.

Despite these hurdles, the researchers point out that by bundling the muscle tissue, their development overcomes a significant barrier in biohybrid scalability. Previously, such devices couldn’t exceed about a centimeter in size, but the 18 cm-long hand marks a major step forward.

“A key goal of biohybrid robotics is to replicate biological systems, which requires scaling up in size,” Takeuchi explained. “Our creation of MuMuTAs is an important milestone toward achieving this. The field is still in its infancy, with many fundamental challenges to address. Once we overcome these basic hurdles, biohybrids could become useful in advanced prosthetics, as well as in studying muscle tissue function in biological systems, testing surgical procedures, or evaluating drugs targeting muscle tissues.”

Read the original article on: New Atlas

Read more: A Robotic Model Equipped with Real Pigeon Feathers Mimics Bird Flight