A team of engineers at Stanford has demonstrated the feasibility of a super-small, implantable cardiac device that gets its power not from batteries, but from radio waves transmitted from outside the body. The implanted device is contained in a cube just eight-tenths of a millimeter in radius. It could fit on the head of pin.
The findings were published in the journal Applied Physics Letters. In their paper, the researchers demonstrated wireless power transfer to a millimeter-sized device implanted five centimeters inside the chest on the surface of the hearta depth once thought out of reach for wireless power transmission.
The paper's senior author was Ada Poon, a professor of electrical engineering at Stanford. Sanghoek Kim and John Ho, both doctoral candidates in Poon's lab, were first authors.
The engineers say the research is a major step toward a day when all implants are driven wirelessly. Beyond the heart, they believe such devices might include swallowable endoscopesso-called "pillcams" that travel the digestive tractpermanent pacemakers and precision brain stimulators; virtually any medical applications where device size and power matter.
A revolution in the body
Implantable medical devices in the human body have revolutionized medicine. Hundreds of thousands if not millions of pacemakers, cochlear implants and drug pumps are today helping people live relatively normal lives, but these devices are not without engineering challenges.
First off, they require power, which means batteries, and batteries are bulky. In a device like a pacemaker, the battery alone accounts for as much as half the volume of the device it drives. Second, batteries have finite lives. New surgery is needed when they wane.
"Wireless power solves both challenges," said Poon.
Last year, Poon made headlines when she demonstrated a wirelessly powered, self-propelled device capable of swimming thro
|Contact: Andrew Myers|
Stanford School of Engineering