A soft, bio-friendly 3D brain-implant electrode

Researchers at Lund University have developed implantable multichannel electrodes that can capture signals from single neurons in the brain over a long period of time, without causing brain tissue damage, making it possible to better understand brain function in both healthy and diseased individuals.
Current flexible electrodes can’t maintain their shape when implanted, which is why they have to be attached to a solid chip. That limits their flexibility and irritates brain tissue, eventually killing surrounding nerve cells and making signals unreliable, says professor Jens Schouenborg.
He explains that recording neuronal signals from the brain requires an electrode that is bio-friendly (doesn’t cause any significant damage to brain tissue) and that is flexible in relation to the brain tissue (the brain floats in fluid inside the skull and moves around whenever a person breathes or turns their head).
“The electrode and the implantation technology that we have now developed have these properties,” he says. Described in an open-access paper in the journal Frontiers in Neuroscience, the new “3-D electrodes” are unique in that they are extremely soft (they even deflect against a water surface) and flexible in all three dimensions, enabling stable recordings from neurons over a long period of time.
But the challenge was how to implant these electrodes in the brain. Visualize pushing spaghetti into a slab of meat. The solution: encapsulating the electrodes in a hard but dissolvable gelatin material, one that is also very gentle on the brain.
“This technology retains the electrodes in their original form inside the brain and can monitor what happens inside virtually undisturbed and normally functioning brain tissue,” said Johan Agorelius, a doctoral student in the project.
This allows for better understanding of what happens inside the brain and for developing more effective treatments for diseases such as Parkinson’s disease and chronic pain conditions, says Schouenborg.