New Horizons for Origami Robots: Inside the Human Body

(Image courtesy of MIT.)
Children swallow small objects, which pose physical or chemical danger to their bodies if not removed. Internal injuries require repair, and the diagnosis of illnesses often requires visual information which can only be acquired through internal cameras. The human digestive tract is difficult to access, and in many cases surgery is required to retrieve items or perform medical procedures below the esophagus. 

However, soon there could be a better option. Researchers are developing technology which could perform these procedures in less invasive ways than surgery or esophageal laparoscopy. 

The latest development from a collaboration between MIT, the University of Sheffield and the Tokyo Institute of Technology is an origami robot which can be swallowed safely and easily, allowing it to perform tasks inside the stomach.

MIT has been researching origami robots for several years.  A prototype developed in 2010 consists of a plastic sheet studded with actuators, allowing it to fold, and magnets, enabling it to hold creased segments together. 

The prototype could fold itself into an “airplane” or “boat” shape along flexible pre-indicated creases, similar to how an origami folder might fold a piece of paper, without cutting or tearing it, in order to create the desired shape.  Since this first prototype, origami robots have become smaller and more capable.

(Image courtesy of MIT.)
The recently developed ingestible robot is made from a biocompatible material derived from pig intestine.  The robot is embedded in a pill-shaped ice capsule which makes it easy to swallow.  Once inside the stomach, the ice capsule melts and the robot is able to unfold, move around and even grab or retrieve items. 

The origami robot maneuvers with a combination of water propulsion, like a swimmer, and a stick-slip friction motion similar to walking.  Movement of the robot is controlled by magnetic fields applied outside the body, eliminating the need for an incision or laparoscopy in order to perform tasks within the stomach.

The research team demonstrated the robot’s capabilities by performing a trial within a synthetic stomach.  The successful trial consisted of using the robot to retrieve a button battery, an item which is swallowed annually by over 3,500 people in the U.S., as an indication of the robot’s potential medical applications. 

Further development of this project will likely involve advanced trials to prepare for this type of origami robot design to be used in medical practice.

More information about this project can be found at the website for MIT’s Computer Science and Artificial Intelligence Laboratory.