Researchers at the Massachusetts Institute of Technology (MIT) have created a tiny robot which looks like a thread or a worm and is designed to crawl through the blood vessels inside the brain. The robot is magnetically controlled and it is made for gliding through the narrow, winding pathways, such as the labyrinthine vasculature of the brain.
The aim of this robotic thread is to create a tool by which the doctors can deliver clot reducing therapies to patients who have blockages and lesions, such as the ones that occur in aneurysms and stroke. The wormlike thread has been developed by Xuanhe Zhao, associate professor of mechanical engineering and of civil and environmental engineering at MIT along with lead author Yoonho Kim, a graduate student in MIT’s Department of Mechanical Engineering.
“Stroke is the number five cause of death and a leading cause of disability in the United States. 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.”
The latest research combines the expertise of hydrogels and biocompatible materials made mostly of water. It also includes 3-D printed materials which are controlled with the help of magnetism. These can crawl, jump, and even catch a ball, simply by following the direction of a magnet. The worm-like robot at its core is made from a nickel-titanium alloy called “nitinol,” which is both bendy and springy.
The robotic thread is coated with a rubbery paste, embedded with particles to give it its magnetic properties. The MIT researchers demonstrated the precision of the robotic worm by using a large magnet to steer the thread through an obstacle course of small rings. This has been described as being similar to guiding a thread through the eye of a needle.
The scientists have also tested this magnetic worm through a silicone replica of major blood vessels of the human brain. The silicone replica was modeled after the CT scans of an actual patient’s brain. The team of scientists filled the silicone vessels with a liquid simulating the viscosity of blood.
This research project was partly funded by the Office of Naval Research, the MIT Institute for Soldier Nanotechnologies, and the National Science Foundation (NSF).