Ingestible Origami Robot Steered by Magnetic Fields

Researchers at MIT developed a tiny ingestible origami robot that unfurls itself from a frozen capsule which, when steered by magnetic fields, can crawl across the stomach and intestinal linings to remove dangerous foreign objects or patch a wound.

Researchers at MIT, the University of Sheffield, and the Tokyo Institute of Technology have recently demonstrated an incredible tiny robot capable of manipulating itself inside a human body without needing any wires or tethers, making it much easier to control. The robot is capable of removing foreign objects that have become lodged, or be used to patch wounds. The new origami robot was presented at the International Conference on Robotics and Automation.

Ingestible origami robot traveling through simulated human gut [Image Source: MIT]

“It’s really exciting to see our small origami robots doing something with potential important applications to health care,”

says Rus, who is also in charge of MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL).

“For applications inside the body, we need a small, controllable, untethered robot system. It’s really difficult to control and place a robot inside the body if the robot is attached to a tether.”

https://youtu.be/3Waj08gk7v8

Although the robot is not the first of its kind, being the successor to another robot presented at another conference the year before, the design and function of the robot is entirely different. The tiny robot is constructed from pig intestine and is propelled using a “stick-slip” motion, where its appendages stick to a surface using friction as it moves- but slides along when the body is flexed, changing the weight distribution causing it to move forward.

However, because the robot is designed for work within a fluid, much of its thrust comes from the propulsion by pushing against the liquid.

“In our calculation, 20 percent of forward motion is by propelling water — thrust — and 80 percent is by stick-slip motion,”

says Miyashita.

“In this regard, we actively introduced and applied the concept and characteristics of the fin to the body design, which you can see in the relatively flat design.”

The robot is also incredibly flexible, able to be folded and frozen inside a capsule where it can be ingested, and unfurled back into its rectangular shape inside the body. It is steered by a magnet which responds to external changing magnetic fields on the outside of the body, controlling its motion. It uses the same magnet to lift metallic objects, for instance, a battery out of the lining where it will cause no harm.

In the U.S. alone, over 3,500 button batteries are swallowed annually. Under normal circumstances, the batteries pass through the digestive tract unobstructed. Occasionally, however, they come into prolonged contact with the tissues in the stomach or esophagus where the exposure causes an electric current that produces hydroxide, which causes burns to the soft tissue. The battery then molds itself into the lining where it becomes lodged until it is medically removed, a potentially dangerous procedure due to all the bacteria present in the area. The engineers in charge of the project devised a clever plan which allows the origami robot to safely remove the battery without the need for another potentially hazardous medical procedure.

The team experimented with a piece of ham, placing a battery on top.

“Within half an hour, the battery was fully submerged in the ham. So that made me realize that, yes, this is important. If you have a battery in your body, you really want it out as soon as possible.”

Says Rus

A professor of robotics at the Swiss Federal Institute of Technology Zurich, Bradley Nelson, says

“This concept is both highly creative and highly practical, and it addresses a clinical need in an elegant way. It is one of the most convincing applications of origami robots that I have seen.”

The robot will see use in medical applications, but will undergo much more testing and modifications as the engineers plan on adding more sensors and a self-propulsion mechanism, as well as adding a camera. The engineers hope to make a smaller version able to reach small areas with more precision to assist in removing things like tumors, or directly administer drugs to specific spaces.

  [Image Source: MIT]

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