In December of 2014, we talked about a new class of futuristic walking biological robots, developed by scientists from the University of Illinois at Urbana-Champaign, which rely on skeletal muscle cells to move around in response to electrical pulse. As part of a new research, the team has recently unveiled an updated and more advanced version of the mobile bio-bots, whose movements are actually controlled by means of light.
Similar to its predecessor in design, the new walking bio-bot is powered by muscle cells that have undergone genetic modification to become sensitive to light. According to the researchers, the ability to respond to light makes the motions of these robots easier to control. The breakthrough, the team believes, could bring about new advances in the field of medicine. Speaking about the study, recently published in the Proceedings of the National Academy of Sciences journal, Rashid Bashir, a professor of the bioengineering department at the University of Illinois and team’s leader, said:
Light is a noninvasive way to control these machines. It gives us flexibility in the design and the motion. The bottom line of what we are trying to accomplish is the forward design of biological systems, and we think the light control is an important step toward that.
The previous research was based on the use of electrical field to prompt the automatons into motion. This approach, however, has its own set of drawbacks. As the scientists point out, electricity is known to cause undesirable side effects to biological environments. Furthermore, it is unable to steer the bio-bots properly, as it fails to selectively stimulate different regions of the muscle. By contrast, the newly-developed technology, which allows the team to maneuver the contraptions with the help of light, is significantly less invasive, and also more dynamic when its comes to guiding the bots in different directions.
The mobile bio-bots, according to the scientists, turn and walk in the direction of a light stimulus. To build the biological walking robots, the team first grow miniature rings of muscle tissues from murine cells. Following this, they genetically alter the muscle cells so as to make them contract every time blue light of a particular wavelength shines on them. This technique, as the group points out, is known as optogenetics. Like the original version, the muscular tissues are then attached to a flexible 3D-printed backbone, measuring around 7 mm to over 2 cm in length. Ritu Raman, a graduate student at the university and the paper’s first author, said:
The skeletal muscle rings we engineer are shaped like rings or rubber bands because we want them to be modular. This means we can treat them as building blocks that can be combined with any 3-D-printed skeleton to make bio-bots for a variety of different applications.
The new bio-bots, the team believes, have several advantages over their predecessors. For instance, their simple, modular design allows nutrients and light to be absorbed by the tissue on all sides. Unlike the former version, which was built using thick strips of skeletal muscle tissues, the new variety is much more flexible and easier to control and monitor. To make the bots stronger and more sure-footed, the researchers regularly exercised the muscle rings, prompting them to contract by flashing light on them. Bashir added:
This is a much more flexible design. With the rings, we can connect any two joints or hinges on the 3-D-printed skeleton. We can have multiple legs and multiple rings. With the light, we can control which direction things move. People can now use this to build higher-order systems.
The research is part of the Emergent Behaviors of Integrated Cellular Systems project. It is being funded by the National Science Foundation.