A snake-like robotic thread can slide into narrow blood vessels in the brain, a promising treatment for stroke

A magnet-controlled snake robot that can maneuver through some of the narrowest arteries in the body may one day help prevent deaths from stroke and aneurysms.

With a magnetic interior and a "growing up" hydrogel that reduces friction, this filiform robot slides seamlessly into "complex and stressed" environments such as vascular structures of the body and brain, say engineers at the Massachusetts Institute of Technology. MIT) of the journal Science Robotics: Associated with currently used endovascular technologies, it can enable physicians to quickly treat the hard-to-reach blockages and brain damage that occur during aneurysms and strokes.

"Stroke is the fifth leading cause of death and one of the leading causes of disability in the United States. If an acute stroke can be treated in the first approximately 90 minutes, the survival rate of patients could increase significantly, "said Xuanhe Zhao, associate professor at MIT, in a statement. "If we could design a device to reverse the blockage of blood vessels during this" golden hour ", we could potentially avoid irreversible brain damage. It's our hope. "

Current treatments are minimally invasive but difficult. To eliminate blood clots in the brain, surgeons run a thin wire through a main artery of the body, often through the leg or groin, while a fluoroscopic emitter emits radiation taking pictures and X-rays to help guide the wire to the brain. A catheter then delivers clot reducing drugs or a device recovers the clot. But this process is challenging and requires specially trained doctors who withstand radiation exposure over time.

"One of the challenges of surgery has been to navigate complex blood vessels in the brain, which has a very small diameter and that commercial catheters can not reach," said Kyujin Cho, professor of engineering. Mechanical at the Seoul National University. . "This research has shown the potential to overcome this challenge and enable surgical interventions in the brain without open surgery."

This is where the robotic yarn comes in, drawing on years of research around water-retaining hydrogels and 3D printed materials that use magnets to crawl and jump. The hydrogel layer keeps the wire smooth and reduces friction by more than 10 times, while the magnets of the second layer allow the surgeon on the outside the part to be used and maneuvering the threads throughout the human body, thus reducing the exposure to radiation emitted by fluoroscopes. Its core is a nickel-titanium alloy, or nitinol, both flexible and able to return to its natural shape, allowing a flexible winding through narrow vessels. Together, the threading is less than a few hundred micrometers in diameter.

"Given their compact, self-contained operation and intuitive handling, our ferromagnetic soft continuum robots could pave the way for minimally invasive robotic surgery for previously inaccessible lesions, responding to unmet challenges and unmet needs. health care, "write the authors.

The researchers tested this technology on a real life silicone replica of the brain's blood vessels with realistic blood clots and aneurysms, as well as a blood fluid. Although promising, the tests were conducted under the eyes of an operator and not under conditions as difficult as when penetrating into the human body. In addition, the magnetic direction was achieved by adjusting the position of a single permanent magnet, and not in a way that could mimic that used in the operating room.

Be that as it may, the authors say that their work could lead to more effective and simplistic treatment in the near future.