Futuristic Medical Implant Powered by Sound Waves

Not so long ago we covered a miniature, ant-sized computer chip designed to be embedded in everyday stuff to make it smarter. Instead of a cumbersome battery in need of constant recharging—the chip is powered wirelessly by radio waves.

Now, the same Stanford group, led by assistant professor of electrical engineering Amin Arbabian, is working on a sister chip destined to be implanted in the body to keep tabs on internal biological processes and distribute drugs and other therapies.

To date, medical implants bristle with wires or, when they’re wireless, are made bulkier by onboard batteries. Ideal implants would be wireless and battery-free.

Arbabian's tiny Internet of Things chip powered by radio waves.

Unlike chips to be embedded in inanimate objects, implanted chips need to be fully compatible with the human body and present minimal health risk. To that end, Arbabian chose ultrasound to power his chip. Ultrasound is already safely used for sensitive procedures, like fetal imaging, and can provide the needed power.

How does it work? The chip houses a special piezoelectric material that flexes in response to incoming ultrasound waves creating a small amount of electricity.

"The implant is like an electrical spring that compresses and decompresses a million times a second, providing electrical charge to the chip," says Marcus Weber, a Stanford graduate student who working on Arbabian’s team.

Arbabian’s team found their device responded to targeted ultrasound through three centimeters of chicken meat—their human flesh analog.