New implant to ease seizures fits snugly into brain

Scientists have developed a brain implant that virtually melts into place, snugly fitting into the brain’s surface.

The technology could pave the way for better devices to monitor and control seizures, and to transmit signals from the brain, past damaged parts of the spinal cord.

“These implants have the potential to maximise the contact between electrodes and brain tissue, while minimising damage to the brain,” said Walter Koroshetz, deputy director, National Institute of Neurological Disorders and Stroke (NINDS).

“They could provide a platform for a range of devices with applications in epilepsy, spinal cord injuries and other neurological disorders,” said Koroshetz.

The study shows that the ultra thin flexible implants, made partly from silk, can record brain activity more faithfully than thicker implants embedded with similar electronics.

The simplest devices for recording from the brain are needle-like electrodes that can penetrate deep into brain tissue.

More state-of-the-art devices, called micro-electrode arrays, consist of dozens of semi-flexible wire electrodes, usually fixed to rigid silicon grids that do not conform to the brain’s shape.

In people with epilepsy, the arrays could be used to detect when seizures first begin, and deliver pulses to shut the seizures down.

In people with spinal cord injuries, the technology has promise for reading complex signals in the brain that direct movement, and routing those signals to healthy muscles or prosthetic devices.

“The focus of our study was to make ultrathin arrays that conform to the complex shape of the brain, and limit the amount of tissue damage and inflammation,” said Brian Litt, study co-author and associate professor of neurology at the University of Pennsylvania’s School of Medicine (UPSM)

The silk-based implants developed by Litt and his colleagues can hug the brain like shrink wrap, collapsing into its grooves and stretching over its rounded surfaces.

The implants contain metal electrodes that are about five times the thickness of a human hair. The absence of sharp electrodes and rigid surfaces should minimise damage to brain tissue.

Also, the implants’ ability to mould to the brain’s surface could provide better stability; the brain sometimes shifts in the skull and the implant could move with it, said a UPSM release.

Finally, by spreading across the brain, the implants have the potential to capture the activity of large networks of brain cells, Litt said.

These findings were published in Nature Material.