Here is a tiny origami robot that can unfold itself from a swallowed capsule to remove foreign objects, patch wounds, and deliver medicine at designated locations. MIT’s Ingestible Origami Robot is steered by external magnetic fields to crawl across the stomach wall.
The challenge was to find bio-compatible materials that can be easily controlled and were compatible with the type of tasks this robot was designed to perform. As the above video explains, this robot can be used to remove button batteries from the body. More information is available on MIT’s website.