For the past years, researchers and engineers alike have been working on a number of robots that are flexible and easy to navigate for different applications from a large scale industrial side to the intricate medical field. In 2008, researchers from the Imperial College London have developed a robot called the i-Snake that was designed to help in sophisticated surgical procedures without being invasive as it was able to work in confined spaces.
Now a team of mechanical engineers in MIT have been working with the Institute for Soldier Nanotechnologies to create a much smaller version of the i-Snake. They have created a thread-like robot which has a diameter of half a millimeter and can be controlled externally using magnetic fields. These thread robots, as the researchers claim in Science Robotics, could be used in drug delivery through blood vessels to break or remove blood clots. They could then treat strokes quickly and prevent brain damage.
Yoonho Kim led the research and together with his colleague Xuanhe Zhao, they used their knowledge in hydrogels and 3D printed magnetically stimulated materials to come up with the design of the robot. The core of the robot was made of nitinol, a nickel-titanium alloy that contributes to the flexibility of the robot, coated with a rubbery compound that allowed the magnetic particles to attach onto its surface. This was then coated with a biocompatible hydrogel, making the entire robot assembly self-lubricating for easy navigation. A magnet is later on used to navigate the robot through its path.
To test its effectiveness, Kim and his team developed a silicone replica of the blood vessels in the brain, filled with a fluid with the same viscosity as blood. They used CT scans as reference and then simulated blood clots and aneurysms. They then used the magnet to course the thread robot through the silicone blood vessels and reach its target.
Further experiments worked the same except that the core nitinol was replaced with an optical fiber. This could then be installed with a laser to break blood clots.
In the future, the team hopes to test their device on living organisms. "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," explained Kim.
