A thread-like robotic worm that can travel through the brain’s blood vessels to deliver drugs for clots and treat blockages and lesions has been developed by engineers at Massachusetts Institute of Technology (MIT).

In a paper titled Ferromagnetic soft continuum robots published in the peer-reviewed research journal Science Robotics, it explained how the “magnetically steerable, hydrogel-coated robotic thread” is controlled by magnets.

This will enable doctors and surgeons to guide it remotely from any location.

Professor of mechanical engineering at Seoul National University Kyujin Cho said: “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.

“This research has shown potential to overcome this challenge and enable surgical procedures in the brain without open surgery.”


How the robotic thread is a safer alternative to treat blood clots

Strokes are among the top five causes of death but if an acute stroke can be treated within ninety minutes of it happening, the survival rates increase significantly.

Traditional methods to treat a blood clot blocking the flow of blood to the brain – also known as ischaemic stroke – are carried out using injections that dissolve blood clots and restore blood flow within the brain.

Another technique requires a thin wire to be inserted into a patient’s body through a main artery in the leg or groin.

This is then manually rotated up into the damaged brain vessel, guided by a fluoroscope, and delivers drugs or clot-retrieval devices to the affected region via a catheter.

Yoonho Kim, a graduate student in MIT’s Department of Mechanical Engineering, explained the procedure can be physically taxing, requiring surgeons, who must be specifically trained in the task, to endure repeated radiation exposure from fluoroscopy.

Fluoroscopy is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object, the risks associated with fluoroscopy include radiation-induced injuries to the skin and underlying tissues burns, which occur shortly after the exposure.

Mr Kim said: “It’s a demanding skill, and there are simply not enough surgeons for the patients, especially in suburban or rural areas.”

Made out of nickel-titanium alloy that is bendable and springy, the robotic thread developed by the MIT team can be used as part of a less exhaustive procedure, as it would not require the same degree of expertise from the surgeon.

The paper states the device is “thin enough to slip through a life-size silicon replica of the blood vessels in the brain.” and that the wire is covered in a rubbery paste filled with magnetic particles.

The whole device is then coated with a biocompatible hydrogel to allow it to slide freely inside blood vessels.

A large magnet allows the device to travel its way past obstacles.

The research team then 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.

Mr Kim added: “Existing platforms could apply magnetic field and do the fluoroscopy procedure at the same time to the patient, and the doctor could be in the other room, or even in a different city, controlling the magnetic field with a joystick.

“Our hope is to leverage existing technologies to test our robotic thread in vivo in the next step.”