A research team of KAIST said it has developed a brain implant device capable of wireless charging. The device can precisely control the brain's neural circuits using optogenetics technologies and a smartphone without the need for battery replacement for a long time. 

The research team of KAIST Professor Jeong Jae-woong at the School of Electrical Engineering said they collaborated with Yonsei University College of Medicine Professor Kim Jeong-hoon at the Department of Physiology to develop a fully implantable wireless optogenetic device for the brain.

Conventional optogenetics devices use optical fibers for light delivery, restricting animals’ movement in animal tests.

Recently developed wireless implants allow free movements of animals but still need regular battery replacements or wireless power transfer for continuous operation.

The left photo shows the tiny wireless device for a brain implant. The picture at the center is a conceptual illustration of a wireless optoelectronic probe system implanted in a rodent head. The photo on the right shows an X-ray image.
The left photo shows the tiny wireless device for a brain implant. The picture at the center is a conceptual illustration of a wireless optoelectronic probe system implanted in a rodent head. The photo on the right shows an X-ray image.

The research team developed a wireless circuit capable of wireless battery charging and wireless device control to address the problems. Then, they combined it with a microscale LED-based probe. 

By doing so, they came up with a device that could be charged wireless while the animal was moving freely and control the wireless implant with a smartphone application. 

The wireless implant device weighs 1.4 grams. To prevent tissue damage after implantation, the device was made of a very soft biocompatible material. 

The research team implanted the device into a mouse's scalp with an LED probe inserted into the brain. They confirmed that the battery charged wirelessly even when the mouse moved freely.

The findings also showed that researchers could apply optogenetics to control addictive behavior by wirelessly delivering light to a specific site of the mouse's brain, which was exposed to cocaine repeatedly. 

The research team said they planned to expand the study to miniaturize the device further for humans and design it into an MRI-friendly one.

“The device can be wirelessly charged while implanted so that it can be used for a long time without the need for additional surgery for battery replacement,” said Jeong, who led the study. “This technology can be widely applied not only to devices for brain implants but also to various devices for implantation such as artificial pacemakers and gastric stimulators.”

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