The magnetic microrobot that could deliver medicine directly to the source

A magnet-powered microrobot small enough to navigate the body’s blood vessels has been developed, delivering medicine directly to targeted areas. Scientists at ETH Zurich, a Swiss university, have developed just that: a microrobot that could revolutionize treatments for strokes, infections, and cancer.

The robot is a spherical capsule made of a dissolvable gel, embedded with iron oxide nanoparticles to make it magnetic. Doctors can track its movement with X-ray technology, guiding it precisely through blood vessels even the narrow and fast-flowing vessels of the brain. “Because the vessels in the human brain are so small, there is a limit to how big the capsule can be,” explains Dr. Fabian Landers, lead author and postdoctoral researcher at ETH Zurich.

The technical challenge is to ensure that a capsule this small also has sufficient magnetic properties.

Navigating the body with precision

Navigating the bloodstream is no small feat. Blood flows at high speeds through a complex network of vessels, with twists, junctions, and branching pathways. To overcome this, the team developed three ways to steer the robot using electromagnets. Depending on the magnetic force applied, the microrobot can roll along the vessel wall, pull against the current, or travel through junctions moving at speeds up to 4 millimetres per second, roughly one inch every six seconds.

The magnets are not just powerful, they are safe. “Magnetic fields and gradients are ideal for minimally invasive procedures because they penetrate deep into the body and at the strengths and frequencies having no detrimental effects on the body,” says Prof. Bradley Nelson, co-author and microrobot researcher at ETH Zurich.

Once the microrobot reaches its target, a high-frequency magnetic field heats the capsule, dissolving its shell and releasing the medicine precisely where it is needed. In tests using silicone models of human and animal blood vessels, as well as live experiments in pigs and the brain of a sheep, the microrobot successfully delivered treatments without affecting surrounding tissue.

The team’s next goal is to move into human clinical trials, bringing this technology from the lab to hospital operating theatres. If successful, it could herald a new era in medicine, where treatments are minimally invasive, targeted, and far more effective, reducing side effects and improving recovery. This invention is a glimpse into the future of medicine, where a tiny magnet could do what no scalpel or syringe ever could.