If you've ever had a child — or had contact with a child, or even seen one on TV — you know that their mouths and hands are magnetized. If there happens to be something grasped in the hot, sticky, little fingers of a toddler, there is a law of science (don't ask which one) that says that object will be pulled upward to the child's open jaws, sampled and probably swallowed. Fact.
This is completely fine if the object is, say, mashed avocado or dog hair. It is less fine if the child's magnet mouth swallows, say, an actual magnet. Or button batteries, which 3,500 people in the U.S. apparently swallow every year. While button batteries often just come out like any digested avocado or dog hair (in the stool, that is), they can cause problems if they're touching the esophagus or stomach for a long time. Pretty major ones, since they can produce electrical currents that burn through the tissue or cause the battery to become embedded.
Enter the origami robot, developed by researchers at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL). The small robot, made up of a small magnet set in a casing of dried pig intestines, enters the body in a swallowed ice capsule. The ice melts, and the capsule unfolds in the stomach. Using an external magnetic field, the robot can retrieve a foreign object (like our button battery), patch wounds and even deliver medicine. It skitters across the stomach, while also using the propulsion from the stomach fluid, to detach an embedded battery so it can pass through the digestive tract and be excreted normally.
Bonus: Because of that irresistible force that pulls the mouths and hands of toddlers together, there will probably be little coaxing necessary to swallow the tiny robot doctor.