Imagine if you could swallow a robot which would come to life once in your stomach and perform basic medical procedures, fixing you from the inside out?
It sounds like something from any one of hundreds of sci-fi books or movies, but now researchers at MIT, the University of Sheffield, and the Tokyo Institute of Technology have come together and built a robot that can do just that.
They have demonstrated a tiny origami robot that can unfold itself from a swallowed capsule and, steered by external magnetic fields, crawl across the stomach wall to remove a swallowed button battery or patch a wound.
“It’s really exciting to see our small origami robots doing something with potential important applications to health care,” says Rus, who also directs MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL). “For applications inside the body, we need a small, controllable, untethered robot system. It’s really difficult to control and place a robot inside the body if the robot is attached to a tether.”
It’s also difficult to steer something precisely around the body using only external magnets, but Rus had a relatively simple first task for the robot: removing a swallowed battery from the stomach.
MIT says that every year in the US there are more than 3,500 reports of swallowed batteries. If left in the stomach or esophagus these can burn the tissue. The researchers suggest that the origami meat robot could be deployed in these scenarios to find the magnet, pulling it free from the tissue and guiding it toward the colon for evacuation.
While further testing is clearly required, the researchers believe they may well be on the way to a novel treatment for button battery ingestion.
“A researcher bought a piece of ham, and he put the battery on the ham,” Rus said in a statement. “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.”
Continuing the challenge of making a robot that could be safely swallowed, the scientists had to decide which material to use to build it. It had to be biocompatible, as patients would essentially be eating it, as well as being degradable, without being dissolved by the stomach’s acid.
They had tested around twelve different possible materials before they found their answer, surprisingly, at a Chinatown market – settling on a type of dried pig intestine often used in sausage casings.
The robot can maneuver through the body using two methods. The primary way it moves is known as “stick-slip” – the robot’s appendages grip onto surfaces using friction, but will slip free again when its body changes the weight distribution, allowing it to move forwards. However, some of the robot’s life is spent in the stomach, so it is also able to move through liquid using propulsion.
Currently, each robot is built with a magnet attached to it, so it can be controlled by magnetic fields outside the body. This primarily allows scientists to rotate the robot, directing it towards the areas in which it is most needed for it to propel itself in the right direction. The team has plans to implement sensors in the robots in the future which would mean they could control themselves and carry out their jobs unassisted.
The robot can deliver medication to specific locations and even patch wounds. However, one of the most compelling applications for the robots would be in their ability to remove foreign objects from the body that could cause potential damage if they remain inside a person for too long once swallowed.
The Future of Medicine?
Though these robots are still in development, the fact that they have been able to perform these tasks under experimental conditions with great success could be a sign that we may well be seeing robots on our prescriptions on future visits to the doctor’s office.