Ingestible origami robot unfolds, operates in simulated stomach

BOSTON, May 12 (UPI) -- Researchers at MIT have already unveiled several iterations of their unfolding "origami" robot. This week, MIT engineers revealed an ingestible version.

Scientists demonstrated the swallowable capsule in a simulated human stomach and esophagus.

"It's really exciting to see our small origami robots doing something with potential important applications to health care," Daniela Rus, director of MIT's Computer Science and Artificial Intelligence Laboratory, said in a news release. "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."

Once inside the stomach, the robot unfolds and can be manipulated using magnetic fields. Scientists designed the robot to retrieve swallowed button batteries and repair small wounds.

A series of slits in the robot design allows it to assume the preset shape when it unfolds. Because the latest iteration of the robot relied on a new biocompatible material -- with a different stiffness -- researchers had to augment their arrangement of slits.

Their previous model relied on a friction-based propulsion mechanism called "stick-slip." The environs of the stomach involved moving through fluids as well as crawling along solid surfaces, so scientists had to adapt their design accordingly.

"In our calculation, 20 percent of forward motion is by propelling water -- thrust -- and 80 percent is by stick-slip motion," explained Shuhei Miyashita, first-author of a new paper describing the ingestible robot.

Researchers said their work involved several trips to meat purveyors at some of Boston's Asian markets. They used dried pig intestine -- commonly used as sausage casing -- to encapsulate their robot. They also modeled their synthetic stomach after a pig stomach.

The robot's design team is set to present their latest invention at this week's International Conference on Robotics and Automation, held in Stockholm, Sweden.