After being approached by a neurosurgeon seeking a less invasive method to treat conditions that require a brain implant, a team of researchers at Switzerland’s Ecole Polytechnique Fédérale de Lausanne led by neurotechnology expert Stephanie Lacour started working. They took inspiration from soft robots to create a large cortical electrode array that can squeeze through a tiny hole in the skull. They published their findings in Science on May 10.
A cortical electrode array stimulates, records, or monitors electrical activity in the brain for patients who suffer with conditions like epilepsy. Epilepsy is relatively common, and affects around 1.2 percent of the US’s population. The disorder is known to cause seizures, which are electrical activity bursts in the brain and may cause uncontrollable shaking, sudden stiffness, collapsing, and other symptoms.
While microelectrode arrays were first invented decades ago, the use of these arrays for deep brain stimulation in epilepsy patients has only became FDA approved in the past handful of years. Even so, current devices often have certain trade offs, be it electrode resolution, cortical surface coverage, or even aesthetics, the authors write in their paper.
The researchers created a superthin flower-shaped device that can be folded small enough to fit a 2 centimeter hole in the skull, where it can rest in between the skull and the surface of the brain—a tiny, delicate area that only measures around a millimeter in width. Once deployed, the flexible electrode releases each of its six spiraled arms one by one to extend across a region of the brain around 4 centimeters in diameter. Other devices may require a hole in the skull the same size as the diameter of the electrode array.
“The beauty of the eversion mechanism is that we can deploy an arbitrary size of electrode with a constant and minimal compression on the brain,” Sukho Song, lead author of the study, said in an EPFL statement. “The soft robotics community has been very much interested in this eversion mechanism because it has been bio-inspired. This eversion mechanism can emulate the growth of tree roots, and there are no limitations in terms of how much tree roots can grow.”
The device, however, isn’t exactly ready for human brains yet—the team has only tested it in a mini-pig—but will continue to be developed by a spinoff of EPFL Laboratory for Soft Bioelectronic Interfaces called Neurosoft Bioelectronics.
“Minimally invasive neurotechnologies are essential approaches to offer efficient, patient-tailored therapies,” Lacour said in the EPFL statement.