Stanford University Assistant Professor Ada Poon has come up with a revolutionary way to wirelessly charge implantable sensors and medical devices in the human body. Because the largest part of an implanted bio-medical device today is the battery, Poon's research opens the doors to have smaller devices and sensors that could be placed in the body and last longer thanks to wireless charging technology.
The wireless charging technology is similar to what's used by smartphones, such as the Qi standard on the Google Nexus 5, and electric toothbrushes today. However, those devices utilize what is called near field charging, where the charger and device must be in extremely close proximity to each other to receive the charge. This means that devices cannot be implanted deep within the human body.
Poon's research builds on that and is reported in the Proceedings of the National Academy of Sciences in the May 19th issue.
In the report, Poon and her researchers developed a small device that's smaller than a grain of rice. That device has small charging coils built in and can be recharged wirelessly with a power source the size of a credit card that could be placed outside of the body.
"We need to make these devices as small as possible to more easily implant them deep in the body and create new ways to treat illness and alleviate pain," Poon said in a statement for Stanford University.
Poon coins her method mid-field wireless transfer, mixing the near field wireless charging technology with far field ideas.
"In the experiment, Poon used her mid-field transfer system to send power directly to tiny medical implants," Stanford said. "But it is possible to build tiny batteries into microimplants, and then recharge these batteries wirelessly using the mid-field system. This is not possible with today's technologies."
Outside of the human body, mid-field technology could also help drive the next wave of wireless charging devices. Rather than having to set your Nexus or Lumia smartphone on a wireless charging pad, larger wireless chargers placed in a briefcase or bag could perhaps one day charge a phone that you're holding a few feet apart in your hands or in your pockets without requiring the phone to make direct contact to the surface of the wireless charger.