Researchers from the University of Twente’s TechMed Centre and Radboud University Medical Centre removed blood clots using wireless magnetic robots. This innovation could revolutionise the treatment of life-threatening vascular diseases such as thrombosis.

Cardiovascular diseases such as thrombosis are a major health problem worldwide. Worldwide, one in four people die each year from conditions caused by blood clots. A blood clot blocks a blood vessel, preventing the blood from delivering oxygen to certain parts of the body.

Minimally invasive approach

Current treatments don’t always work for clots in hard-to-reach places. But magnetic microrobots offer hope for patients with otherwise inoperable blood clots. These tiny helical robots can navigate through complex blood vessels, without the need for wires.

In a new study, researchers Islam Khalil (University of Twente) and Michiel Warlé (Radboudumc) show the potential of these microrobots for precise and minimally invasive clot removal. In their experiments, the microrobots removed enough material from a blood clot in a femoral artery to resume blood flow. The femoral artery of a sheep was chosen because of its straight and accessible structure.

Their article, titled “Wireless mechanical and hybrid thrombus fragmentation of ex vivo endovascular thrombosis model in the iliac artery,” is published in the journal Applied Physics Reviews.

Three methods

The study tested three methods: mechanical fragmentation, chemical dissolution and a combination of both. The combined approach proved to be the safest and most effective, because it not only breaks the clot, but also dissolves the fragments. “By completely dissolving them, we prevent them from causing a new clot further down the line,” Warlé explains. Using X-ray images, the small robot precisely targets clots in complex blood vessels.

“The transatlantic collaboration has been incredibly rewarding for my team. These robots are designed to swim and perform deep surgery, but researchers have been limited to using models and video cameras or ultrasound probes with limited range. Real-time x-ray guidance of these small robots is a critical leap forward in this field. We’ve long imagined what it looks like, but now we have 3D reconstructions of blood clots as the robot dissolves them,” said Aaron Becker, a researcher at the University of Houston.

The robots are 3D-printed and shaped like tiny screws, each with a small permanent magnet. “This tiny magnet, just one millimeter long and one millimeter in diameter, is what allows the ‘screw’ to rotate in both directions,” Khalil explains. “This allows the robot to swim against the blood flow and then turn around and swim back.” The screw-like design allows them to effectively drill through blood clots.

More widely applicable

In addition to removing blood clots and restoring blood flow in arteries, the technology can be used for other targeted treatments. “The robots can deliver drugs precisely to where they are needed,” Khalil explains. “This approach minimizes side effects in the rest of the body.”