Researchers have constructed and demonstrated a small voltaic cell which is sustained by stomach acids. This ingestible cell can generate sufficient power to run small drug delivery devices or small sensors which can dwell in the gastrointestinal tract for a long time.
This offers a longer-lasting, lower-costing and safer alternative to the currently used traditional batteries. The study has been published in the journal Nature Biomedical Engineering.
They derived inspiration for designing this from a lemon battery, a simple type of voltaic cell. This consists of a two electrodes stuck in a lemon. The small electric current between the electrodes is carried by lemon’s citric acid content.
To reproduce this method, they attached copper and zinc electrodes to the surface of an ingestible sensor. The zinc emits ions into the stomach acid to power the voltaic circuit. This produced enough current to power a 900-megahertz transmitter and a commercial temperature sensor.
"A big challenge in implantable medical devices involves managing energy generation, conversion, storage, and utilization. This work allows us to envision new medical devices where the body itself contributes to energy generation enabling a fully self-sustaining system," says Chandrakasan, another co-author.