MIT researchers develop ingestible paper battery for medical devices

Researchers, including a team from MIT, have developed a biodegradable, paper-thin battery designed to power medical devices inside the human body before dissolving completely. The technology, detailed in the journal Nature Chemical Engineering, utilizes a magnesium alloy anode, a molybdenum trioxide cathode, and a biodegradable electrolyte bound by cellulose nanofibrils.

To prevent rapid degradation from stomach acid, the batteries are coated in beeswax or candelilla wax. In animal trials involving pigs, the devices successfully powered electronics for up to three days. Tested applications included a wireless ingestion monitor to track medication adherence and a capsule designed for electrical stimulation of the stomach lining to influence hunger hormones.

The battery is available in two sizes: a small version that fits inside a standard gelatin capsule for low-power electronics, and a larger version with a maximum capacity of 3.5 milliampere-hours. While promising, researchers noted that challenges regarding electrolyte distribution and coating thickness must be addressed before human testing can begin.