MagFlow and OmniMag, guided by a stylus. 2025 EPFL/Alain Herzog CC BY SA
EPFL researchers have invented a remarkably small and ultraflexible neurovascular microcatheter. Powered by blood flow, it can safely navigate the most intricately branched arteries in a matter of seconds.
Microcatheters are medical devices that can snake through the body's blood vessels to deliver lifesaving therapies - for example to treat clogged arteries, or to stop bleeding. They can also be used to cut off blood flow to a tumor or deliver highly targeted chemotherapy.
Until now, interventional neuroradiologists have used guidewires to painstakingly ease microcatheters around blood vessels' tortuous twists and turns using a time-consuming push-pull-torque technique, which risks damage to vessel walls. But even these instruments are too large to reach the furthest and most highly branched blood vessels in the brain, which can be smaller than 150 microns in diameter - about the size of a human hair.
To overcome these challenges, researchers have been developing untethered microrobots that can be guided to a treatment site using magnetic fields or acoustic waves. But Selman Sakar, head of the MicroBioRobotic Systems Laboratory in EPFL's School of Engineering, thinks that with an updated design, catheters can still do the job best.
"Catheters eliminate concerns about device removal after use, and don't have limited payloads. At the same time, many blood vessels lie beyond a traditional catheter's reach," Sakar explains. "That's why we have developed and tested MagFlow: an ultraminiaturized magnetic microcatheter - twice as small as benchmark microcatheters - that minimizes contact with vessel walls by hitching a ride on the blood stream's own kinetic energy."
New pathways in medicine
The concept for MagFlow was originally described in 2020 as a ribbonlike, flat polymer device (in contrast to traditional endovascular instruments, which are round) with a magnetic tip. Now, in collaboration with interventional neuroradiologist Pascal Mosimann of Toronto Western Hospital (Canada), Sakar and recent EPFL graduate Lucio Pancaldi have turned this concept into a fully functional microcatheter. Two bonded polymer sheets allow the device's body to inflate "like a fireman's hose" to deliver thin or viscous biomedical liquids.
In parallel, the EPFL team developed a robotic steering platform, OmniMag, that allows the microcatheter to be guided using a robotic arm-mounted magnetic field generator. Using the doctor's hand movement on a stylus, OmniMag automatically calculates the orientation of the magnetic field required to point MagFlow's magnetic tip in the desired direction.
We are very excited about this patented technology and want to push it further - we are in the process of launching a startup venture.
In experiments carried out at a research facility in Paris, the team demonstrated MagFlow's unique capabilities by catheterizing extremely narrow and curved arteries in the head, neck, and spine of pigs to deliver contrast and embolizing (clogging) agents safely and rapidly. The results of these experiments have been published in Science Robotics.
"Our experimental results elevate the flow-driven navigation concept into a viable clinical solution that can ultimately unlock new treatment avenues for cardiovascular conditions," Pancaldi summarizes.
Looking ahead, the scientists see potential for MagFlow to access the blood vessels in adult patients suffering from hemorrhagic stroke or arteriovenous malformations, as well as in pediatric cancer patients. They say their technology has already sparked interest in the medical community, and they are currently working with clinicians at the Lausanne University Hospital (CHUV) and Jules Gonin Eye Hospital to develop MagFlow for use in retinoblastoma treatment. "We are very excited about this patented technology and want to push it further - we are in the process of launching a startup venture," Sakar says.
He adds that beyond catheterization, the innovative technology opens the door to exciting applications in neurology. "We are working with neurosurgeons and epileptologists at Inselspital Bern to develop electrodes that can navigate through blood vessels using the MagFlow concept to map seizure activity in a minimally invasive fashion."
