Ingestible Origami Robot Successfully Removes Button Battery Stuck to Wall of Stimulated Stomach

Researchers at Massachusetts Institute of Technology (MIT), the University of Sheffield, and the Tokyo Institute of Technology have developed a tiny origami robot that can be ingested and deployed in the stomach to perform internal surgeries, such as the removal of button battery stuck to the wall of the stomach or patching internal wounds.

"It's really exciting to see our small origami robots doing something with potential important applications to health care," said Daniela Rus, the Andrew and Erna Viterbi Professor in MIT's Department of Electrical Engineering and Computer Science, in a statement.

"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," added Rus.

For their new unfolding robot, the researchers designed it to be a rectangular robot with accordion folds perpendicular to its long axis and pinched corners that act as points of traction. They also attached a permanent magnet in the center of one of the forward accordion folds.

The accordion-like folds of the miniature robot make it possible to be compressed into a capsule for swallowing. The robot will start to unfold as the capsule dissolves.

For the robot's mobility inside the stomach, researchers use changing magnetic fields outside the body to control the robot with the help of the mounted magnet. The robot also doesn't rely that much on stick-slip motion.

 "In our calculation, 20 percent of forward motion is by propelling water -- thrust -- and 80 percent is by stick-slip motion," said first author Shuhei Miyashita, who was a postdoc at CSAIL when the work was done and is now a lecturer in electronics at the University of York, in England, in a press release.

"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 researchers tested their new unfolding origami robot in a simulated stomach made from silicone rubber and is filled with water and lemon juice to mimic the acidic fluids in the stomach.

In their experiment, the capsule successfully dissolves in the mixture, releasing the unfolding origami robot. With the use of the mounted magnet in the robot, it was able to to remove a button battery stuck to the stomach wall.

The researchers noted that the robot may soon play a significant role in the health care industry, especially in the removal of swallowed button batteries and the treatment of consequent wounds.