Wireless power gives life to ingestible devices

Powering gastrointestinal tools requires a safe, strong power source capable of being swallowing, but current methods often come up short. Researchers from Brigham and Women's Hospital (BWH), the Massachusetts Institute of Technology and the Charles Stark Draper Laboratory have developed an ingestible electronic capsule powered wirelessly outside of the body, with findings published in Scientific Reports.

The new capsule includes antennas capable of receiving a wireless radio signal to power a device within the gastrointestinal tract.

"Electronic devices that can be placed in the gastrointestinal tract for prolonged periods of time have the potential to transform how we evaluate and treat patients. This work describes the first example of remote, wireless transfer of power to a system in the stomach in a large preclinical animal model—a critical step toward bringing these devices into the clinic," said co-corresponding author Carlo Traverso, MD, PhD, a gastroenterologist and biomedical engineer at BWH.

Modeled after cochlear implants and neural probes that can be powered wirelessly, researchers developed the capsule to be ingestible and remain a significant distance from the surface of the body while still receiving a signal.

Using mid-field coupling, which provides higher frequencies to power devices up to three times more efficiently, researchers tested the capsule by attaching antennas on the outside of the body and in the esophagus, stomach and colon of a pig. The device was able to receive power levels of 37.5 microwatts, 123 microwatts and 173 microwatts, all capable of powering a medical device from outside of the body.

"In further work, we would like to expand on these measurements by characterizing the effects of animal size, antenna depth, orientation and more on transmission efficiency, and focus on propagating fields—or the way power travels—to make transmission even more efficient," said Traverso.