Researchers at ETH Zurich have developed tiny magnetic microrobots designed to carry medicine through the body and release it exactly where treatment is needed. The system was created to improve targeted drug delivery in places that are difficult to reach, such as narrow brain blood vessels involved in stroke.
The microrobot is a very small spherical capsule made from a dissolvable gel shell. It contains iron oxide nanoparticles so it can be steered with magnetic fields, and tantalum nanoparticles so doctors can track it with X ray imaging while it moves through the body.
Once the capsule reaches the target area, doctors can apply a high frequency magnetic field. This heats the magnetic particles, dissolves the shell, and releases the drug cargo directly at the treatment site. The goal is to keep the medicine concentrated where it is needed instead of spreading large doses throughout the whole body.
That targeted approach is especially important for stroke care. Standard clot dissolving drugs can increase the risk of serious bleeding when given systemically. By delivering the medication directly to a clot in the brain, the microrobot could potentially lower side effects while improving treatment precision.
The study, “Clinically Ready Magnetic Microrobots for Targeted Therapies,” was published in Science in 2025. In the reported tests, the team showed precise navigation in realistic silicone models of blood vessels and successful tracking and delivery in large animal studies, including pigs and sheep.
The researchers reported that the system delivered the capsule to the correct location in more than 95 percent of tested cases. They also showed that the same platform could potentially be adapted for other treatments, including antibiotics for localized infections and drugs for tumors.
This work is an important step toward precision medicine, but it is still in the preclinical stage. Human clinical trials had not yet begun at the time of the reports, so the technology remains promising rather than available for routine patient care.