The use of magnetic resonance imaging (MRI) is a cornerstone of modern medicine, providing detailed images of tissues and organs that can reveal even subtle injuries, inflammation, and tumors. However, the strong magnetic fields and radio waves used in MRI pose challenges when combined with other medical procedures, particularly those involving electrical stimulation.
Metallic objects are problematic within an MRI environment. They can heat up, potentially causing burns, even if not directly attracted by the magnetic field. This represents particularly concerning when patients require simultaneous MRI and procedures like electrocardiograms (EKGs), electroencephalograms (EEGs), or transcranial alternating current stimulation (TI), all of which rely on electrodes connected to devices via cables.
Currently, these combined procedures require patients to wear electrodes on their chest or head, connected by cables – typically made of copper – to a measurement device. These copper cables can heat up within the MRI, and also interfere with the quality of the MRI image itself. Researchers have been seeking solutions to mitigate these risks and improve the feasibility of combined MRI and stimulation techniques.
Researchers at Empa’s “Advanced Fibers” laboratory in St. Gallen, Switzerland, in collaboration with TI Solutions AG, have developed a novel solution: MRI-compatible polymer cables. Instead of traditional copper wiring, these cables are primarily constructed from plastic, utilizing bundles of polymer fibers coated with an extremely thin layer of metal. , February 4, 2026, this development represents a significant step forward in the safety and efficacy of medical brain stimulation.
“Our goal was to develop a cable with a very low, but precisely defined metallic conductivity,” explains Dirk Hegemann, a researcher involved in the project. “The conductivity must be large enough to transmit the signal, but not so large that it interacts with the radio waves.” This careful balance is crucial for ensuring both functionality and safety within the MRI environment.
TI Solutions AG, specializing in electrodes for stimulation and measurement of brain currents, particularly using TI and EEG, was an ideal partner for this project, which was funded by Innosuisse. Sven Kühn, Research Leader at TI Solutions, stated that the new “MRIComplead” cables, developed at Empa, provide medical research partners with the first opportunity to visualize the effects of TI in the brain safely and without interference during MRI scans.
Robust and Scalable Design
The desired electrical conductivity is just one requirement the new cables needed to meet. For clinical and research applications, they also needed to be durable and resistant to corrosion and mechanical stress from repeated plugging and unplugging. The research team tested around a dozen different coatings with varying materials and techniques.
A coating composed of silver and titanium proved to be the most effective. “Silver has very good electrical conductivity,” Hegemann explains. “Titanium reduces the conductivity somewhat, allowing us to reach our specified range.” The combination of the two metals also provides enhanced corrosion resistance. Initial testing over a year showed minimal change in the cables’ conductivity.
The ultra-thin coating, less than half a micrometer thick, was applied to the fibers using magnetron sputtering, a well-established process that can be scaled for industrial production in a roll-to-roll process. The Empa researchers have already produced approximately one kilometer of coated fibers. The Innosuisse project was successfully completed in 2025.
Despite the project’s completion, the collaboration continues. Hegemann stated that they will continue to support their industrial partner with demonstrators and initial samples. Niels Kuster, President of TI Solutions AG, highlighted the efficient and uncomplicated support from Empa during the initial phase as a key benefit of the partnership.
If the plastic cables prove successful in these initial applications, they will move into full-scale industrial production, potentially revolutionizing the field of combined MRI and brain stimulation. This innovation promises to enhance the safety and accuracy of medical imaging and therapeutic interventions, ultimately benefiting patients and advancing neurological research.
