New Soft Implant Allows for Smartphone-Based Braincell Control with Free-Moving Wireless Charging

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) and Yonsei University have released a paper describing a prototype soft brain implant that can be charged wirelessly and allows for the control of braincells from a connected smartphone.

"This powerful device eliminates the need for additional painful surgeries to replace an exhausted battery in the implant, allowing seamless chronic neuromodulation," explains project lead Professor Jae-Woong Jeong of the project, which builds on a 2019 paper describing drug delivery and light stimulation via a smartphone-connected implant. "We believe that the same basic technology can be applied to various types of implants, including deep brain stimulators, and cardiac and gastric pacemakers, to reduce the burden on patients for long-term use within the body."

"This device can be operated anywhere and anytime to manipulate neural circuits," adds the paper's lead author Choong Yeon Kim, who works as a researcher at KAIST, "which makes it a highly versatile tool for investigating brain functions."

The new implant features a wireless energy harvester, coil antenna, and a Bluetooth Low Energy (BLE) readio for connection to a controlling smartphone. To charge the device, an alternating magnetic field is generated — passing harmlessly through living tissue to charge the device. The smartphone, meanwhile, can communicate with the implant over BLE to deliver programmable light patterns to braincells — offering, the researchers claim, "real-time brain control."

To prove that claim, the researchers implanted the device in lab rats then injected them with cocaine — before using the implants, via smartphone, to suppress cocaine-induced behavior through light-based stimulation of target neurons. During the experiment, the implants were charged even as the rats were moving around freely — minimizing the physical interruptions that would traditionally be required for charging.

"The fact that we can control a specific behaviour of animals, by delivering light stimulation into the brain just with a simple manipulation of smartphone app, watching freely moving animals nearby, is very interesting and stimulates a lot of imagination," says Professor Jeong-Hoon Kim, of Yonsei University's College of Medicine. "This technology will facilitate various avenues of brain research."

The paper has been published under open-access terms in the journal Nature Communications.