MIT News image courtesy of the researchers.
Engineers in the United States have developed a magnetically steerable, thread-like robot that may actively slip through narrow, winding pathways like brain's tiny blood vessels.
The study published on Wednesday in the journal Science Robotics revealed that the magnetically controlled device could in a day deliver clot-reducing therapies in response to stroke or other brain blockages.
Now, to clear blood clots in the brain, surgeons need to insert a thin wire through a patient's main artery, usually in the leg or groin, and manually rotate the wire up into the damaged brain vessel, guided by a fluoroscope that images the blood vessels using X-rays.
However, the procedure is physically taxing, requiring surgeons who must be specifically trained in the task, to endure repeated radiation exposure.
Researchers from the Massachusetts Institute of Technology (MIT) created a robotic thread core made from bendy, springy nickel-titanium alloy, and they coated the wire core in a rubbery paste filled with magnetic particles.
Then, they bonded the magnetic covering with a kind of hydrogel that gives the thread a slippery, friction-free surface, but does not affect the responsiveness of the magnetic particles, according to the study.
The researchers tested the thread in a life-size silicone replica of the brain's major blood vessels modeled after scanning an actual patient's brain. Those silicone vessels also have clots and abnormal sacs.
They filled the vessels with a liquid simulating the viscosity of blood, then successfully manipulated a large magnet around the model to steer the robot through the vessels' winding, narrow paths.
The team demonstrated that the thread's wire core can also be replaced with an optical fiber that can activate the laser once the robot reached a target region to clear blockages.
They are preparing to test the robotic thread in vivo, according to the researchers.
