Last updated October 25, 2018 at 1:19 pm
This robot is controlled by actual living muscles.
In what sounds like a terrifying science fiction story, Japanese scientists have unveiled part of a biohybrid robot which uses living muscle tissue to move.
The finger-like joint used living muscles which contracted or extended in response to electrical signals, allowing it to grab objects.
It’s an important step forward for biohybrid robots, which have traditionally struggled to generate force, and have a limited lifespan due to the living cells drying out and losing function.
However, the researchers have suggested that their techniques could be used beyond just robotics and could find use in development of pharmaceutical drugs, and could even reduce the reliance on animal studies by providing a substitute model for testing.
Biohybrid what now?
Rather than just using metal or plastic, biohybrid robots incorporate living tissue within the robot structure.
Muscle is one obvious potential key component of such robots, providing the driving force for movement and function.
However, rather than removing a whole muscle from a living animal, the team from the University of Tokyo decided to create their own. And then taking more inspiration from nature, they created not one muscle, but two opposing muscles which allowed movement in both directions.
The team first 3D printed a robot skeleton on which to install the pair of functioning muscles. This included a rotatable joint, the anchors to attach the muscles, and electrodes to provide the electrical signal that made the muscles contract.
The muscle cell-laden hydrogel sheets exhibited properties of skeletal muscle tissues. Credit: Morimoto, Onoe, Takeuchi, Sci. Robot. 3, eaat4440 (2018)
They then attached muscle precursor cells called myoblasts growing in a specially shaped hydrogel that encouraged the muscle fibres to form in an aligned manner that mimicked normal skeletal muscle.
“Once we had built the muscles, we successfully used them as antagonistic pairs in the robot, with one contracting and the other expanding, just like in the body,” said Shoji Takeuchi, who was one of the researchers who developed the biohybrid.
“The fact that they were exerting opposing forces on each other stopped them shrinking and deteriorating, like in previous studies.”
While the muscles did eventually degrade, it was only after a (relatively) long period of 1 week.
Living muscles controlling a robotic joint. Credit: Copyright 2018 University of Tokyo
Giving it the finger
To test their set up, the team used a single finger to pick up and place a ring of plastic, followed by two fingers working in unison to pick up a heavier square frame.
Not only did the muscles respond and contract in response to the electrical signals, they could flex the joint by around 90° and create enough force to hold the objects, paving the way for larger trials.
“Our findings show that, using this antagonistic arrangement of muscles, these robots can mimic the actions of a human finger,” lead researcher Yuya Morimoto said.
“If we can combine more of these muscles into a single device, we should be able to reproduce the complex muscular interplay that allow hands, arms, and other parts of the body to function.”
However they’re not only looking at robotic joints. They hope that there could be applications for this setup in pharmaceutical and medical research. With more work they are hoping to create an organic chip – a 3D whole tissue used in medical research, which they suggest could lead to a reduced reliance on using whole animals in experiments, including research mice and rats.
But in the near future their focus is on making robots work and act more like a living body – or even better than. Rather than just placing muscles in parallel but opposite directions, they’ve begun considering the possibilities of placing the muscles at angles to each other, potentially opening up an even wider range of complex motion and force.
The research has been published in Science Robotics
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