MIT engineers have built a soft robotic enteroscope designed to crawl through the small intestine and help doctors diagnose and treat disorders there. The tube-like robot moves in a way inspired by snakes and carries tools for imaging, drug delivery and tissue removal.A hard-to-reach organThe small intestine is more than 20 feet (6 meters) long and about an inch (2.5 centimeters) in diameter, and it sits deep inside the body. That makes it harder to examine than the stomach or colon.Doctors most often need to evaluate bleeding, lesions and blockages there. Today, the only way to diagnose those problems is double balloon enteroscopy, where a health care worker alternately inflates and deflates two balloons to propel the scope. The process is slow and laborious.The MIT team wanted an enteroscope that is easier to control and moves faster through the intestine. Traverso said the aim is to evaluate the 20-to-25-foot (6-to-7.6-meter) segment in a more automated way.How it slithers forwardA snake steers by contracting muscles on one side of its body, then the other. To mimic that, the researchers designed multifunctional actuators that control the robot’s movement. Each actuator has four chambers that can be inflated in different combinations, making the tube extend or bend in any direction.Adjusting the air going into those chambers lets operators “tune the direction that the robot is moving in,” Traverso said.The head and tail segments carry extra anchoring balloons that take turns inflating and deflating to help the robot inch forward. Those segments are covered with patterned sleeves inspired by kirigami, an origami variant that adds cuts to the folds.The coatings lie flat until the balloon beneath them expands and stretches them, which makes three-dimensional kirigami needles pop out. Like the scales of a snake, the needles give the robot more traction on the slippery intestinal lining.Traverso’s lab has used the same approach for shoe soles that grip better and for stents that can temporarily lodge in the esophagus and release drugs. Graduate student Ahmad Mujtaba Jebran, a lead author, said the sleeves let the robot gain traction at specific spots without overstretching the delicate tissue.Tools and early testsThe robot is tethered by a cable to external controllers, and an operator can steer it through narrow passages and around tight corners. It is designed to enter the body through either the mouth or the rectum.Its tools include a camera for imaging, a sprayer for drug delivery and clips that can take tissue biopsies or remove polyps. Traverso said the robot lets doctors “take a biopsy or remove it” if they find a small polyp.In animal studies, the robot traveled about 6.5 feet (2 meters) through the small intestine. The team also demonstrated the drug sprayer, tissue clips and camera. The researchers are now improving the navigation systems and testing the approach for additional small intestine applications.Traverso is a mechanical engineering professor at MIT, a gastroenterologist at Brigham and Women’s Hospital and an associate member of the Broad Institute of MIT and Harvard. The paper’s lead authors are Binbin Ying, a former MIT postdoc now at the University of Texas Southwestern Medical Center, Jebran and former MIT research scientist Sahab Babaee.The research appears in Science Robotics, with MIT’s Giovanni Traverso as senior author.