A Soft Robot Is Learning to Snake Through the Small Intestine
The small intestine is the hardest part of the digestive tract to examine.
It runs more than 20 feet, measures about an inch across, and sits deep inside the body.
MIT engineers have now built a soft robot that moves through it the way a snake moves across the ground.
Why the small intestine is so hard to reach
Bleeding, lesions, and blockages are the most common problems doctors need to evaluate in this organ.
The only current way to diagnose them is double balloon enteroscopy.
In that procedure, a health care worker alternately inflates and deflates two balloons to pull the scope forward.
The process is slow and laborious, which is what the MIT team set out to change.
How the robot moves
Each actuator in the robot contains four air chambers that inflate in different combinations.
That lets the tube extend or bend in any direction.
Balloons at the head and tail take turns inflating, which anchors the robot and inches it forward.
Those segments are wrapped in sleeves inspired by kirigami, a paper art that involves cutting as well as folding.
When a balloon stretches the sleeve, tiny needles pop out and grip the slippery intestinal lining, much like snake scales.
The researchers say this gives traction without overstretching delicate tissue.
What it can do once it arrives
The robot carries a camera for imaging, a sprayer for drug delivery, and clips that can take biopsies or remove small polyps.
An operator steers it with a handheld controller through narrow passages and around tight corners.
It stays tethered to external controls by a cable and can enter through either the mouth or the rectum.
That puts diagnosis and treatment into a single pass.
What the evidence shows so far
In animal studies, the robot traveled about six and a half feet through the small intestine.
That covers roughly a quarter to a third of the 20 to 25 foot segment doctors need to evaluate.
The camera, sprayer, and clips all worked in those studies.
The results come from animal work, not patients.
The team is now improving navigation and testing additional uses in the small intestine.
The stated goal is a more automated way to evaluate the entire organ.
