Researchers have devised a way to wirelessly power small electronic devices that can linger in the digestive tract indefinitely after being swallowed. Such devices could be used to sense conditions in the gastrointestinal tract, or carry small reservoirs of drugs to be delivered over an extended period.
The new strategy is based on the wireless transfer of power from an antenna outside the body to another one inside the digestive tract. This method yields enough power to run sensors that could monitor heart rate, temperature, or levels of particular nutrients or gases in the stomach.
The research team has been working for several years on different types of ingestible electronics, including sensors that can monitor vital signs, and drug-delivery vehicles that can remain in the digestive tract for weeks or months. Using midfield transmission, the researchers delivered 100–200 mW of power to their device, more than enough to power small electronics. In a study conducted in pigs, the external antenna transferred power over distances ranging from 2–10 cm. The energy transfer caused no tissue damage.
The researchers are continuing to explore different ways to power devices in the GI tract, and they hope that some of their devices will be ready for human testing within about five years.