The more advanced a medical intervention is, it seems, the less invasive it is to perform. For example, bariatric surgery once entailed opening a patient's abdomen from navel to diaphram; today such operations are done laparoscopically through incisions mere centimeters in size. Now researchers at the Massachusetts Institute of Technology have built a prototype robot that can perform simple procedures inside the stomach without any incisions or external tethers at all—the patient just swallows it.
Once in the digestive tract, the micro robot, encased in a lozenge of ice, makes its way to the stomach. The ice melts, and the robot unfolds like a piece of origami. The unfurled robot, which looks like a wrinkled sheet of paper, moves by virtue of strategically placed folds, slits and patches of material that expand or shrink when exposed to heat or magnetic fields; these points of movement work like joints and muscles. Surgeons pilot the robot from the outside using electromagnetic fields to act on an onboard magnet. The robot can also crawl into position by flexing the folds of its body against the walls of the stomach in what is known as stick-slip motion.
The robot's biocompatible body—partially fabricated out of pig intestine (like that used in sausage casings)—can deliver medication to an internal wound or patch it by settling onto the injury like a Band-Aid. The robot can also use its magnet to “pick up” and remove a foreign object, such as a swallowed button battery.
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Credit: AXS BIOMEDICAL ANIMATION STUDIO; Source: “Ingestible, Controllable, and Degradable Origama Robot for Patching Stomach Wounds,” by Shuhei Miyashita et al. Presented at the 2016 IEEE International Conference on Robotics and Automation, Stockholm, Sweden, May 16–21, 2016
The robot has yet to be tested in humans or live animals. But M.I.T. robotics engineer Daniela Rus, whose group conducted the research, considers it a successful proof of concept for “even more capable robots” that might one day use onboard sensors to diagnose the source of internal bleeding. The ability to remove objects without traumatic surgery would be a huge leap. “My father had a kidney stone in the 1970s, and they essentially sliced half of his body open to extract this thing,” Rus says. “It will take a number of years before [micro robots] become feasible, but if it does, just imagine what this method could do for these procedures.”