Magnetic tiny robots deliver drugs directly to clots to fight strokes

Researchers at ETH Zurich have developed magnetic microrobots designed to deliver clot-dissolving drugs directly to stroke-causing thrombi, achieving over a 95% success rate in targeted drug delivery. These tiny spherical capsules feature a soluble gel shell embedded with iron oxide nanoparticles for magnetic guidance and tantalum nanoparticles for X-ray tracking. The microrobots are precisely navigated through blood vessels using a modular electromagnetic system that combines three magnetic strategies, enabling controlled movement at speeds up to 4 millimeters per second along vessel walls. This targeted approach aims to reduce the side effects associated with systemic clot-dissolving drugs, such as internal bleeding. The microrobots release their drug payload when heated by a high-frequency magnetic field, dissolving the gel shell at the target site. Tested in realistic silicone vessel models, the robots successfully located and dissolved blood clots, and further in vivo trials demonstrated effective navigation in pigs and sheep, including through complex cerebral fluid environments. Beyond stroke treatment,