An ingestible origami robot is capable of unfolding itself from a swallowed capsule and crawling across a person’s stomach wall to remove swallowed objects or patch injuries. The research group of Daniela Rus, the Andrew and Erna Viterbi Professor in MIT’s Department of Electrical Engineering and Computer Science, has presented studies on these origami robots proving that their capabilities can be applied to health care situations someday.
The robot succeeded in its first mission: removing a swallowed battery from the stomach; batteries trapped within the stomach or esophagus lining must be removed before they release hydroxide and cause tissue damage. The situation played out in tests with a folded sheet of dried pig intestine (the same substance used in sausage casings) and a tiny magnet. When the robot is equipped with the magnet, doctors can control it from outside the body. Having the power to alter magnetic fields also permits the doctors to rotate the robot so it may remove a button battery stuck in the stomach.
Shuhei Miyashita, a lecturer in electronics at England’s University of York and a first author on the project’s paper, was able to persuade Rus to use their robot design for medical treatment. “Shuhei bought a piece of ham, and he put the battery on the ham,” Rus said in an interview with MIT News. “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.”
Such demand for this kind of solution is evidenced by statistics – in the U.S. alone, 3,500 swallowed button batteries are reported on a yearly basis. A previous model of the robot bore a considerably different design, but shares the current robot’s feature of “stick-slip” motion, through which the robot can propel itself by sticking to a surface when it moves, before changing its weight distribution to slip free. Unlike the older model, the newer version is made from the pig intestine, which is a biocompatible material. The robot’s design ultimately improved to accommodate fewer slits and allow for compression.
The researchers tested the updated origami robot in a model of an open-cross section of the stomach and esophagus, simulating the mechanical properties of a pig’s stomach. The team also filled the model with water and lemon juice to imitate the stomach’s acidity. Once inserted into the body, the robot must pull the battery from the stomach tissue and guide it toward the colon for evacuation. Doctors’ control over the robot at this step is crucial, as it is “difficult to control and place a robot inside the body if the robot is attached to a tether,” said Rus.
While the final version of the robot capsule is still in progress, the team – compiled of researchers from MIT, the University of Sheffield, and the Tokyo Institute of Technology – has confidence about the design’s potential. “It’s really exciting to see our small origami robots doing something with potential important applications to health care,” said Rus. In the upcoming months, the team’s next mission is to add sensors to the robot so that it can control itself in the absence of an external magnetic field.
Source: MIT News
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