Researchers from the Massachusetts Institute of Technology, Brigham and Women’s Hospital and the Charles Stark Draper Laboratory have developed the means to wirelessly power electronic devices that stay in the digestive tract indefinitely. The team suggests that these devices could be used as sensors in the GI tract or carry drugs to be delivered over a controlled period of time.
An efficient power source is a crucial part of developing ingestible electronic devices and that has previously stumped researchers.
“If we’re proposing to have systems reside in the body for a long time, power becomes crucial,” co-senior author Giovanni Traverso said in prepared remarks. “Having the ability to transmit power wirelessly opens up new possibilities as we start to approach this problem.”
The team published their work in the journal Scientific Reports. They developed a way to wirelessly transfer power from an antenna outside of the body to another antenna inside the patient’s digestive tract.
“Right now we have no way of measuring things like core body temperature or concentration of micronutrients over an extended period of time, and with these devices you could start to do that kind of thing,” first author Abubakar Abid said.
The team has previously explored galvanic cells as a power source for ingestible electronics. However, the metal electrodes in that type of battery eventually stops working. So the researchers set out to engineer a way they could avoid using electrodes.
They decided to explore midfield transmission as a way to transfer power between antennas. Using this method, the team delivered 100 to 200 microwatts of power to their device, which is suitable for small electronics.
In a pig model, the external antenna was able to transfer power from 2 to 10 centimeters away. The team added that the energy transfer did not cause any tissue damage.
“We’re able to efficiently send power from the transmitter antennas outside the body to antennas inside the body, and do it in a way that minimizes the radiation being absorbed by the tissue itself,” Abid said.
“This is a classic problem with implantable devices: How do you power them? What they’re doing with wireless power is a very nice approach,” Carnegie Mellon University’s Christopher Bettinger said. He was not involved in the research.
The researchers said they hope that some of their devices for the GI tract will make it to the clinic for testing in humans within 5 years.
“We’re developing a whole series of other devices that can stay in the stomach for a long time, and looking at different timescales of how long we want to keep them in,” Traverso said. “I suspect that depending on the different applications, some methods of powering them may be better suited than others.”