Brain-computer interfaces and other technologies that rely on reading and stimulating the brain require electrodes to obtain and deliver signals, as well as a way to transmit those signals from within the brain. Electric wires have usually served as the method of connectivity, but they create serious challenges, including potential for infection, safety issues, and lack of discreetness. Wireless technologies have a lot of promise, but most approaches require a battery or another source of energy to power an implant to beam data back and forth from deep within the brain.
Researchers at Purdue University have now developed a brain-reading implant that’s incredibly small and that doesn’t need any on-board batteries to power it. Instead, the device, which the researchers say is about the size of a piece of dust, relies on externally delivered electromagnetic waves to power it. It’s conceptually similar to how wireless charging works in some modern smartphones. The implant was produced from a commercially available electronic chip that was modified to include microelectrodes.
The device is able to gather electric signals from a number of nerve endings at the same time. It can also be flexible, an important point for implants positioned within tissue resembling gelatin. A tiny antenna works as the energy harvester to power the system.
“The main challenges are to operate such a wireless neural interface system with a small and flexible chip at very low power and yet high data rate,” said Saeed Mohammadi, one of the researchers on the project. “We need a high data rate to be able to read signals from thousands of neurons using a single implant chip. At the same time, we need to operate the system at very low power for safety and size reasons.”