A team at ETH Zurich has unveiled magnetic microrobots designed to deliver drugs directly to targeted sites in the human body, offering new possibilities for treating strokes, infections, and tumors. This innovation addresses a critical medical challenge: every year, millions of patients suffer strokes, and current therapies require high systemic doses of clot‑dissolving drugs that can cause severe side effects. By guiding medication precisely to the blocked vessel, the ETH Zurich microrobots promise safer and more effective treatment.
The microrobots are engineered as spherical capsules with a soluble gel shell. Embedded within the shell are iron oxide nanoparticles that allow magnetic control and tantalum nanoparticles that make the capsules visible under X‑ray imaging. This dual functionality enables physicians to both steer and monitor the microrobots inside the body. Once the capsule reaches the target site, a high‑frequency magnetic field heats the nanoparticles, dissolving the shell and releasing the drug exactly where it is needed. This controlled release reduces systemic exposure and minimizes risks such as internal bleeding.
Navigation is one of the most difficult challenges in microrobotics, and the ETH Zurich team developed a modular electromagnetic system to overcome it. The system combines three strategies: rotating magnetic fields, magnetic gradients, and in‑flow navigation. Together, these methods allow the microrobots to move through complex vascular networks and even against strong currents exceeding twenty centimeters per second. In laboratory trials, the microrobots successfully reached the correct location in more than ninety‑five percent of cases, demonstrating remarkable precision.
To validate the technology, researchers tested the microrobots in silicone vessel models that replicate human and animal blood vessels. These models are now marketed by ETH spin‑off Swiss Vascular for medical training, underscoring the broader impact of the project. Animal trials in pigs and sheep further confirmed that the microrobots could navigate both blood vessels and cerebrospinal fluid, proving their versatility across different biological environments.
The clinical potential of this technology is significant. For stroke patients, microrobots could deliver thrombolytic drugs directly to clots, reducing the need for high systemic doses and lowering the risk of complications. For infections, they could transport antibiotics to localized sites, improving efficacy while limiting resistance. For cancer, they could release chemotherapy agents directly into tumors, sparing healthy tissue from toxic exposure. These applications highlight how microrobotics could transform minimally invasive medicine.
Here’s a cool video from ETH Zurich showing a microbot dissolving a simulated thrombus:
Article from ETH Zurich: Microrobots finding their way
Abstract in Science: Clinically ready magnetic microrobots for targeted therapies
