Normally, it might seem weird to let a snakelike robot sliver through your brain. But scientists at MIT have found the exception with a soft robot prototype that can be magnetically guided to clear neurological blood clots or treat strokes and aneurysms, according to a study published on Wednesday in Science Robotics.
Blood clots are lumps of coagulated blood that can form in many parts of the body, but they are particularly dangerous in the brain, where they can cause severe headaches, cerebral hemorrhage, and stroke. Brain blood clots can be treated with drugs, but they can also be cleared out by a procedure called mechanical thrombectomy.
This treatment involves inserting a miniature device into the femoral artery, on the upper thigh of a patient, and using a metal wire thread to manually guide it to the brain to remove the clot. It is a laborious process that can only be performed by specialized surgeons who are exposed to radiation doses from X-rays that keep track of the device inside the patient. These doses are not dangerous in isolation, but the more frequently a person is exposed to them, the higher the risk of tissue damage.
A team led by Yoonho Kim, a graduate student in mechanical engineering at MIT, proposed a new method of thrombectomy using a slicker robot that can be steered by magnetism. This means doctors could operate the robot remotely, removing the need for them to be directly exposed to X-ray radiation.
The robot’s spine is made of a flexible nickel-titanium alloy, which is covered in a paste filled with tiny magnetic beads, and coated with a polymer that makes gliding through arteries a relatively friction-free affair.
Kim’s team successfully guided a prototype of the robot through a life-size replica of the brain’s vascular structure, and the researchers hope to miniaturize the concept so that it can be tested in living blood vessels.
One day, doctors might equip the robots with drugs or lasers that could be delivered to problem areas in the brain. This type of minimally invasive technique may also be useful in mitigating damage from neurological emergencies such as strokes, according to study co-author Xuanhe Zhao, an associate professor at MIT
“If acute stroke can be treated within the first 90 minutes or so, patients’ survival rates could increase significantly,” Zhao said in a statement. “If we could design a device to reverse blood vessel blockage within this ‘golden hour,’ we could potentially avoid permanent brain damage. That’s our hope.”
Correction: A version of this article said that the robot prototype was guided through a scaled-up model of the brain. The model was life-size, not scaled-up. The article has been updated to reflect this.