Robots, as in automated electro-mechanical devices often imitative of humans or animals, have been around for quite some time. Such machines are usually controlled by highly complex circuitry, centered around an electric motor. A significant development in recent times is the growth of bio-inspired automatons, using biosensors and other biomaterials. Researchers at the University of Illinois at Urbana-Champaign have taken this field to extraordinary heights, with their new “bio-bot” design. In a revolutionary attempt to demonstrate the potential of biological machines, the scientists have developed a group of tiny, walking bio-bots, whose movements are controlled by actual muscle cells.
The team, led by Rashid Bashir, has previously experimented with mobile bio-bots, powered by rat heart cells. One major challenge in this case, however, is the fact that heart cells continually contract, thereby making it difficult for the engineers to accurately control the motions of these biological machines. Using muscle cells, on the other hand, allows one to regulate the bot’s movements to a greater extent. Consequently, the group has designed a class of one-centimeter-long bio-bots, using 3D-printed hydrogels and functional live-cells. Talking about the research, published in Proceeding of the National Academy of Science’s online edition, Rashid Bashir, the head of the Department of Bioengineering at the University of Illinois, said:
Biological actuation driven by cells is a fundamental need for any kind of biological machine you want to build. We’re trying to integrate these principles of engineering with biology in a way that can be used to design and develop biological machines and systems for environmental and medical applications. Biology is tremendously powerful, and if we can somehow learn to harness its advantages for useful applications, it could bring about a lot of great things…Our goal is for these devices to be used as autonomous sensors. We want it to sense a specific chemical and move towards it, then release agents to neutralize the toxin, for example. Being in control of actuation is a big step towards that goal.
Each of these robots possesses a narrow piece of skeletal muscle cells, which are in turn powered by electrical pulse. The scientists created the body of the biological automatons, based on the complex muscle-tendon-bone arrangement found in humans and animals. The backbone is made of incredibly strong and flexible 3D-printed hydrogel. Similar to the way tendons affix muscles to bones, the muscle strip is attached to the hydrogel backbone by means of a pair of miniature posts. The posts also serve as the bot’s feet. Bashir said:
Skeletal muscles are very attractive because you can pace them using external signals. For example, you would use skeletal muscle when designing a device that you wanted to start functioning when it senses a chemical or when it received a certain signal. To use, it’s part of a design toolbox. We want to have different options that could be used by engineers to design these things.
The speed of these walking bio-bots is determined by the frequency of the electrical pulse applied to the muscle cells. The higher the frequency, the greater is the speed and vice-versa. While the research is still at its initial stage, the team hopes that with further advancement in technology, it would acquire greater freedom to control the bio-bot’s movements, especially in different directions and in response to different stimuli. For instance, incorporating neurons into this setup allows the scientists to steer the robots in the direction of light or chemical changes. Talking about the significance of the breakthrough, Caroline Cvetkovic, the paper’s first author along with Ritu Raman, said:
The work represents an important first step in the development and control of biological machines that can be stimulated, trained or programmed to do work. It’s exciting to think that this system could eventually evolve into a generation of biological machines that could aid in drug delivery, surgical robotics, ‘smart’ implants or mobile environmental analyzers, among countless other applications.
The research was conducted in association with the Massachusetts Institute of Technology and the Georgia Institute of Technology, and was funded by the National Science Foundation’s Emergent Behavior of Integrated Cellular Systems grant.
Via: Illinois News Bureau