Biomimicry: Light-Activated Skeletal Muscles for Robots


Biomimicry is the word descending from the words ‘Bios’ and ‘Mimesis’ which implies `Life’ and `to imitate’. It is a discipline that inquires about the best designs of nature and using them to solve the complex issues that humans are facing. A number of paragons can be quoted as examples of Biomimicry. For instance, a building that resembles cactus is under construction in Qatar. The building is designed in such a way that it is more energy efficient. Taking the inspiration from cactus plant and its dealing with the climate in the desert, the building has sunshades to adjust the heat entering the place.

(Image Credit – Aesthetics Architects)

Recently, researchers from MIT thought of mimicking behaviors of animals in a robot was not enough, so they came up with the idea of mimicking the materials that are genetic thus paving way for bio robots that are very feasible and flexible.

Harry Asada along with MIT postdoc Mahmut Selman Sakar collaborated with Roger Kamm, the Cecil and Ida Green Distinguished Professor of Biological and Mechanical Engineering to genetically engineer their own muscle cells. Being the Ford professor of Engineering in MIT’s Department of mechanical engineering, Harry Asada has said that the group’s work has effectively bridged the boundary between machines and nature.

Unlike cardiac muscles that beat involuntarily, an external stimulus is required to cause a flex(motion) in the skeletal muscle. In a living organism, the external stimulus is provided by the neurons. In genetically engineered muscles, electrodes are used to stimulate the muscles and thereby help in causing a flex. However, this team engineered the muscles genetically in such a way that they responded to light instead of electrodes. They thought that electrodes would add too much arrangement to the robot.

A new theory called optogenetics (A neuromodulation technique that uses a combination of techniques from genetics and optics thereby controlling the neuron that is present in the living tissue) was used by these researchers. Here, the neurons that were genetically modified, responded to a light source (Short Laser Pulses). This team cultured cells that fused myoblasts(long tubular cells that later develop into a muscle fiber) and found the result to be quite interesting, the fibers that were genetically altered responded in a different manner. When small beams of light were focused on a particular fiber, it caused only that fiber to contract, whereas when the beam covered multiple fibers, the whole part and the fibers associated with them experienced contraction.

Now the team went a step ahead grew muscle fibers that had hydrogel. Now, this muscle tissue when exposed to the light reacted in a similar way that individual fibers did. They twisted and bended like the individual fibers.

When this engineered tissue was tested using a micro mechanical chip for its strength, it exhibited a wide range of motions which can empower robots that have high flexibility and articulation. When the tissue was secured to the two flexible posts of the micro mechanical chip, it curved the posts inwards when excited with light. However, this engineered tissue regularly needed exercise for its effective function. This micro chip and the genetically engineered tissue can be used to screen drugs for diseases that are motor-related.

The team is currently involved in making an endoscopic device that can travel through the body while lighting the path. This robot may even travel through the body`s vasculature. Having multiple applications in locomotion, navigation and medical devices, this design will definitely pave way in making robotic animals.

Check out the video of how the genetically engineered muscles responded to laser pulses here.


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