Exploring better implants for treating epilepsy
A recent news item released by the University of Glasgow, Scotland, reports breakthrough research on materials that could help new types of probes be safely implanted in the brain. Supported by the EU-funded HERMES and INTUITIVE projects, the research has the potential to bring us one step closer to a cure for a type of epilepsy. In their study published in ‘Advanced NanoBiomed Research’, the Glasgow researchers and their colleagues from the University of Modena and Reggio Emilia and the Italian Institute of Technology, Italy, investigated new dissolvable coatings that could help safely guide flexible implants into brains. If this were to be achieved, it might be able to regulate temporal lobe epilepsy, a disorder that can resist drug therapy. According to the news item, neural probes capable of deep brain stimulation are a promising treatment for this type of epilepsy. At the moment, deep brain stimulation probes are made from silicon. This results in scarring around the site where the probe is implanted “because of a mismatch between the stiffness of the artificial materials and the soft tissue of the brain.” Flexible probes made from new, bendable materials could be better suited for implantation in the soft brain tissue. However, since greater flexibility may lead to a higher risk of the probes bending or breaking when inserted into the brain tissue, this needs to be solved before they can be used as implants.
Four materials under the microscope
The team therefore studied four different biological materials as stiffening coatings for flexible neural probes: sucrose, maltose and silk fibroin that had also been tested in previous research, as well as alginate, a naturally occurring polysaccharide found in brown seaweed. These temporary stiffeners could enable probes to reach their target without bending or breaking, and would then dissolve after the implantation was complete. Of the four materials, the researchers found that silk fibroin performed the best, increasing the force needed for a probe to buckle when introduced into brain tissue from 0.31 millinewtons (mN) – for an uncoated probe – to 75.99 mN. This was followed by alginate, which increased the buckling force up to 15 mN, while sucrose and maltose showed no significant increase in the buckling force. Tests were also conducted to see how long the coatings took to dissolve in brain-like conditions. The silk fibroin and alginate materials lasted longer than the other two materials before dissolving, which in practice could provide neurosurgeons with more time to implant the probes. The team then tested the silk fibroin materials in samples of lambs’ brains and in rat brains to gain more information on how they would perform in human-like brains. “The tests we conducted show some really promising results for creating coatings for future flexible neural probes that could help safely guide them to their targets in the brain,” states study lead author Maria Cerezo-Sanchez from the University of Glasgow. “It’s an exciting step forward, and we’re continuing to explore the potential of these materials for use in neural implant procedures.” Both HERMES (Hybrid Enhanced Regenerative Medicine Systems) and INTUITIVE (INnovative Network for Training in ToUch InteracTIVE Interfaces) end in 2024. For more information, please see: HERMES project website INTUITIVE project website
Keywords
HERMES, INTUITIVE, epilepsy, brain, implant, brain tissue, neural probe, coating, silk fibroin
