Swarms of microscopic, magnetic, robotic beads could be used within five years by vascular surgeons to clear blocked arteries. These minimally invasive microrobots, which look and move like corkscrew-shaped bacteria, are being developed by an $18-million, 11-institution research initiative headed by the Korea Evaluation Institute of Industrial Technologies (KEIT).
These “microswimmers” are driven and controlled by external magnetic fields. They are made from chains of three or more iron oxide beads, rigidly linked together via chemical bonds and magnetic force.The beads are put in motion by an external magnetic field that causes each of them to rotate.
Because they are linked together, their individual rotations cause the chain to twist like a corkscrew and this movement propels the micro swimmer. The chains are small enough — the nanoparticles are 50–100 nanometers in diameter — that they can navigate in the bloodstream like a tiny boat.