MIT researchers have developed a magnet-based robot that can unfold from an ingested capsule and then get to work in the stomach.
Robots are performing any number of jobs that humans used to do. Increasingly, that includes surgery; soon, it could be surgery performed by teeny, tiny robots, swallowed by patients.
At the IEEE International Conference on Robotics and Automation
in Stockholm May 16-21, Daniela Rus, director of MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL); Steven Guitron, a graduate student in mechanical engineering at MIT; Kazuhiro Yoshida with the Tokyo Institute of Technology; Dana Damian of the University of Sheffield, in England; and Shuhei Miyashita, now a lecturer at the University of York, in England, will present a centimeter-long folded robot (pictured)
that can be swallowed in a capsule and is controlled by an external magnetic field.
When the pill capsule reaches the stomach and dissolves or melts (ice has been experimented with, as a way of transporting the robots, and so has the type of dried pig intestines used for sausage casings), the robot unfolds itself and gets to work.
What type of work?
In the United States alone, 3,500 button batteries—the tiny silver circles used to power watches, toys, games, singing greeting cards and so much more—are swallowed
every year by people of all ages, according to the National Capital Poison Center
. The 20mm, 3-volt batteries can burn through a child's esophagus in 2 hours and cause life-threatening injuries.
"Shuhei [Miyashita] bought a piece of ham, and he put the battery on the ham," Rus said in an interview with MIT News
. "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."
An MIT News
video shows a robot landing in the stomach, finding a battery embedded in esophageal lining and lifting it out. It then directs it toward, ahem, disposal through the expected channels.
The robots can also patch a tear or deliver medicine to a specific location.
The robots build on work the researchers presented a year ago
at the same conference.
A year ago, the robots showed off weighed 0.31 grams and measured 1.7 cm on each side of laser-cut polystyrene or paper layers. Heat prompted the robots to fold themselves, and they could move around on land or in water and eventually completely dissolve.
Their origami folds, not their magnets, enabled them to move. They had an asymmetrical design that, combined with an off-center balance point, forced their front and back legs to alternately tap the ground, creating the equivalent of a marching motion that propelled them forward.
These newest robots are made of more biocompatible materials—after tests with about a dozen materials, the sausage casings were determined to be an ideal material. They also propel themselves differently, in part because the earlier robots' so-called "stick-slip" motion only works well with a stiff material.
The new robots are more rectangular, with perpendicular accordion folds. The design also enables the robot to be compressed enough to fit in a capsule.
Bradley Nelson, a professor of robotics at the Swiss Federal Institute of Technology Zurich, has called the robots a creative, highly practical and elegant way to address a real clinical need.
"It is one of the most convincing applications of origami robots that I have seen," he told MIT News
Research firm Markets and Markets
expects the market for global medical robots—which spans from surgical and rehabilitation robots to those that help with pharmacy and telemedicine—to reach $11.4 billion by 2020, from an estimated $4.2 billion in 2015.
Similarly, Stratistics MRC
expects the health care robotics market to reach $17.9 billion by 2022, encouraged by the rising Baby Boomer population and rising incidences of disabilities, and challenged by what it calls "towering purchase and installation costs."
There may well be an enthusiastic market, then, for a solution comprised of a pepper-seed-size magnet and a slice of pig intestine.