MIT creates robotic thread designed to crawl through the human brain

MIT engineers have developed a thread-like robot that can glide through the narrow blood vessels of the human brain. the magnetically controlled device could enable doctors to remotely deliver clot-reducing therapies in response to stroke or other brain blockages.

dubbed ‘robo-thread’, the technology is designed to treat blockages and lesions, such as those that occur in aneurysms and stroke. this would involve a minimally invasive surgery to insert the thin wire through the patient’s main artery.

MIT engineers have developed robotic thread (in black) that can be steered magnetically and is small enough to work through narrow spaces such as the vasculature of the human brain
images courtesy of MIT

using a fluoroscope that simultaneously images the blood vessels using x-rays, the surgeon would then manually rotate the wire up into the damaged brain vessel. a catheter can then be threaded up along the wire to deliver drugs or clot-retrieval devices to the affected region.

‘stroke is the number five cause of death and a leading cause of disability in the united states,’ says xuanhe zhao, associate professor of mechanical engineering and of civil and environmental engineering at MIT. ‘if acute stroke can be treated within the first 90 minutes or so, patients’ survival rates could increase significantly.’

‘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 researchers envision the technology may be used in the future to clear blockages in patients with stroke and aneurysms.

the medical guidewires typically used in such procedures need to be manipulated manually and so requires a surgeon who is specifically trained to endure repeated radiation exposure from fluoroscopy. a magnetically steerable guidewire does away with the necessity for surgeons to physically push a wire through a patient’s blood vessels, which means that doctor’s wouldn’t need to be in close proximity to a patient and the radiation-generating fluoroscope.

these wires are also typically made from a core of metallic alloys, coated in polymer and so there is potential to generate friction and damage vessel linings if the wire gets temporarily stuck in a particularly tight space. MIT”s research involves using a soft water-based hydrogen and 3d-printed materials controlled by magnetism. a soft snake-like robot has, at its center, a nickel-titanium alloy which is both bendy and springy. the team coated the wire’s core in a rubbery paste, or ink, which they embedded throughout with magnetic particles.

researchers thread the robo-thread through an obstacle course of small rings, reminiscent of a thread working its way through the eye of a needle

MIT has demonstrated the robotic thread’s precision by using a large magnet to steer it through an obstacle course of small rings. this is described as being similar to guiding a thread through the eye of a needle. the researchers also tested the thread in a life-size silicone replica of the brain’s major blood vessels, modelled after the CT scans of an actual patient’s brain.

‘one of the challenges in surgery has been to be able to navigate through complicated blood vessels in the brain, which has a very small diameter, where commercial catheters can’t reach,’ says kyujin cho, professor of mechanical engineering at seoul national university. ‘this research has shown potential to overcome this challenge and enable surgical procedures in the brain without open surgery.’

project info

research body: MIT

project: robo-thread