International. Bioengineering researchers at the University of Glasgow investigate new soluble coatings that could help safely guide flexible implants into the brain to help regulate temporal lobe epilepsy.
The development of the material is part of an EU-funded collaboration that aims to tackle epilepsy by treating and regenerating damaged brain tissue.
The €8 million Hermes project, Hybrid Systems of Enhanced Regenerative Medicine, brings together 12 partners from seven EU countries to find new ways to cure brain disorders through transplants that combine biological and artificial components.
Neural probes capable of deep brain stimulation are a promising future treatment for temporal lobe epilepsy, which can be drug-resistant. Currently, deep brain stimulation probes, which are made of silicone, often cause scarring around the implantation site due to the mismatch between the stiffness of the artificial materials and the soft tissue of the brain.
One solution could be a new generation of flexible probes made from new flexible materials that better match the softness of brain tissue. Flexible implants could also expand the possibilities of where implants could be placed in the brain, opening up treatments for more conditions.
However, the increased flexibility of the materials can increase the risk of the probes bending or rupturing when introduced into brain tissue, a key problem that needs to be solved.
Researchers have explored the potential of four different biological materials as coatings for future Hermes implants. The materials act as temporary reinforcements, which could allow flexible probes to reach their target in the brain without bending, before dissolving once surgery is complete.
They examined the performance of sucrose, maltose, silk fibroin and alginate as reinforcements for a flexible probe such as the one to be used in the HERMES project.
While three of the materials had previously been tested in the lab as reinforcements in previous research, the Glasgow team was the first to explore alginate, a natural polysaccharide extracted from algae, as a reinforcement material.
They coated flexible probes similar to those that will be used in future Hermes implants in samples of the materials. They tested their performance as boosters by examining their performance when inserted into blocks of agarose gel, a material with a consistency similar to real brain tissue.
Longer duration probes
The alginate-coated probes performed well, increasing the force required to bend from 0.31 millinewtons for an uncoated probe to 28.97 millinewtons. However, silk fibroin worked better, increasing the force required to bend the flexible probe to 75.99 millinewtons.
They also tested the material's potential biocompatibility by performing chemical tests and measuring how long it took to dissolve under brain-like conditions. Again, the silk fibroin and alginate materials worked well, lasting longer than the other materials before dissolving, which could offer surgeons more time to successfully perform Hermes implant operations.
Maria Cerezo-Sanchez, from the James Watt School of Engineering, said: "The tests we conducted show some really promising results for creating coatings for future flexible neural probes that could help guide them safely to their targets in the brain."
"It's an exciting step forward and we continue to explore the potential of these materials for use in neural implant procedures," Sanchez added.
