The new field of biohybrid robotics involves the use of living tissue amalgamated with robotic structures to engineer cybernetic entities. Muscle is a potentially viable component of these robots, with the hope this tissue will one day provide independent energy for movement and function. However, efforts to integrate living muscle into machines have been problematic due to their rapid deterioration. Now, a study from researchers at the University of Tokyo develops a new method with the ability to develop individual muscle precursor cells into fully functioning skeletal muscle tissues. The team states they incorporated these muscles into a biohybrid robot as antagonistic pairs mimicking those in the body and were able to maintain continued muscle function for over a week. The study is published in the journal Science Robotics.
Previous studies show rapid progress has been occurring in biohybrid robotics, particularly those involving skeletal muscle grown on a flexible substrate enabling various types of locomotion powered by the tissue. However, it has been difficult to achieve high levels of both large and long-term actuation of the skeletal muscle tissues because of their spontaneous shrinkage through the course of the tissue culture. The current study melds skeletal muscle with a robotic substrate to perform tasks whilst mimicking human movement.
The current study constructs a robotic skeleton incorporating a pair of functioning muscles. The lab uses hydrogel sheets containing muscle precursor cells called myoblasts to grow muscle tissues using holes in the substrate to attach the tissue sheets to the robot skeleton anchors, and stripes to encourage the muscle fibers to form in an aligned manner. Results show the muscle fibers successfully act as antagonistic pairs in the robot, with one contracting and the other expanding, just like in the body. Data findings show they exert opposing forces on each other meaning they don’t shrink and/or deteriorate.
The team also tested the robots in different applications, including having one pick up and put down a ring and having two robots work in unison to hoist a square frame. Results show the robots perform these tasks well, with activation of the muscles leading to flexing of a finger-like protuberance at the end of the robot by around 90 degrees. Data findings show using this antagonistic arrangement of muscles enables these robots to mimic the actions of a human finger.
The team surmises they have developed a biohybrid robot powered by an antagonistic pair of skeletal muscle tissues capable of the biomimetic manipulation of objects. For the future, the researchers state if they can combine more of these muscles into a single device, it should be possible to reproduce the complex muscular coordination seen in hands, arms, and other parts of the body.
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