Small, drug-releasing battery could dissolve completely over time

A magnesium-based battery dissolves completely over time (clockwise).--Courtesy of U. of Illinois

A study published this week in Advanced Materials highlights a biodegradable battery that could be designed to deliver drugs in a controlled manner and then disappear within a set amount of time.

The implantable device uses magnesium foil as its anode and iron, molybdenum or tungsten as its cathode, all of which dissolve in the body over time. Held together in the biodegradable polymer polyanhydride, the battery uses a phosphate-buffered solution as an electrolyte between the two electrodes, according to an article in Nature.

In further research, the creators, who hail from the University of Illinois, hope to turn these batteries into delivery devices that can be implanted in the body and then controlled by radio signals to release their payload. This could happen in response to a specific signal, such as that of a seizure, according to the article.

And once it's dissolved, the battery releases about twice as much magnesium as a dissolving stent, an amount that isn't considered to be dangerous in the body.

For now, the device can be used for about one day at a time, but the team is looking to improve its capability while keeping its size at a reasonable level. They say that a 0.25-square-centimeter battery that is just a micrometer thick could eventually power a wireless sensor for a day.

- here's the Nature report
- and here's the Advanced Materials abstract