Stanford Researchers Develop Wireless Cardiac Technology

Sept. 26, 2012, 1:25 a.m.

New wireless technology developed by Stanford researchers could eliminate the need for batteries in implantable medical devices.

A team of researchers, led by assistant professor of electrical engineering Ada Poon, designed a new kind of medical device that functions on radio waves rather than a battery. This technology allows implantable devices to be driven by a small power source that can be worn on the outside of the body.

“Batteries suffer from two flaws that are fatal for many applications,” wrote John Ho, a graduate student who worked on the device, in an email to The Daily. “One, they are large – typically several centimeters in one dimension. Two, they must be periodically replaced, which requires surgery.”

While batteries are notoriously bulky, the device created by Poon’s team can be contained in a cube that measures 0.8 millimeters on each side, meaning it can fit on the head of a pin.

The team hopes that removing the battery could lead to the creation of medical devices, such as permanent pacemakers or swallowable endoscopes, which will let doctors get an inside view of intestinal tracts without any pain.

“We envision tiny devices that can relay vital information outside the body, move through the bloodstream or even perform local interventions,” Ho said.

Despite the potential for advancement that this device provides, however, researchers are still working to ensure that complications with human tissue heating do not arise as a result of the wireless technology, according to Sanghoek Kim, another doctoral candidate in Poon’s lab who assisted with the research.

Kim, whose role focused on power-transfer efficiency, said that human tissue can be a “lossy medium,” meaning that it’s important to ensure that the wireless power is transferred to the device properly instead of being lost in the body as heat.

The research team said stringent Institute of Electrical and Electronics Engineers regulations were met in order to ensure that the device does not overheat to the point where excessive damage occurs to the human body.

Other potential complications include the unpredictable nature of a wireless link, which could require a backup power source to be implemented for life-or-death devices, like pacemakers. The team is continuing to work on perfecting the device and finding solutions to problems such as this.

“Overall,” Kim said, “[this technology] will make patients more comfortable, and surgery more simple and less dangerous.”

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