For years, scientists have been trying to create implantable electronic devices, but challenges related to powering such technologies has limited their success. Enter a prototype developed by Stanford engineer Amin Arbabian, PhD, and colleagues that uses ultrasound waves to operate the device and send commands.
As explained in a Stanford Report story, researchers designed the "smart chip" to use piezoelectricity, or electricity generated by pressure, as a source of power and selected ultrasound because it has been extensively, and safely, used in medical settings:
[The researchers'] approach involves beaming ultrasound at a tiny device inside the body designed to do three things: convert the incoming sound waves into electricity; process and execute medical commands; and report the completed activity via a tiny built-in radio antenna.
"We think this will enable researchers to develop a new generation of tiny implants designed for a wide array of medical applications," said Amin Arbabian, an assistant professor of electrical engineering at Stanford.
Every time a piezoelectric structure is compressed and decompressed a small electrical charge is created. The Stanford team created pressure by aiming ultrasound waves at a tiny piece of piezoelectric material mounted on the device.
"The implant is like an electrical spring that compresses and decompresses a million times a second, providing electrical charge to the chip," said Marcus Weber, who worked on the team with fellow graduate students Jayant Charthad and Ting Chia Chang.
The prototype is about the size of a ballpoint pen head, but the team ultimately wants to make it one-tenth that size. Arbabian and his colleagues are now working with other Stanford collaborators to shrink the device even further, specifically to develop networks of small implantable electrodes for studying brains of laboratory animals.
Previously: Miniature wireless device aids pain studies, Stanford researchers demonstrate feasibility of ultra-small, wirelessly powered cardiac device and Stanford-developed retinal prosthesis uses near-infrared light to transmit images
Photo by Arbabian Lab/Stanford School of Engineering