Over the past several years, scientists have developed so-called “camera pills,” that can be swallowed by patients and then transmit video from within their bodies. While such non-digestible gadgets could serve as an invaluable means of imaging, researchers at Carnegie Mellon University are now looking into tiny electronic medical devices that could be swallowed and partially digested, providing non-invasive treatment in the process.

The research project is being led by professors Christopher Bettinger and Jay Whitacre. Bettinger has been working on biodegradable electronics for medical use, while Whitacre has developed an inexpensive, non-toxic, sodium-ion electrochemical battery.

“I had claimed my device was so non-toxic that you 'could eat the battery’,” said Whitacre. “Chris came into my office and asked, 'Can you really eat it?'. The answer is yes and the rest is history – my edible battery chemistry with his need for low level power in a digestible form were a great match.”

The concept involves having simple electronic devices such as sensors, drug delivery systems or tissue-stimulating tools powered by the batteries, and made from a biodegradable shape-memory polymer. These devices would be folded down and encased within a gelatin capsule, allowing for a timed release at a key point in the gastrointestinal tract. When the capsule dissolved, the polymer would hydrate, thus initiating electrical current flow from the battery, and causing the device to open into its operational form.

The capsules could be taken daily like regular medication, and the devices would stay within the patient’s digestive system for about 18 to 24 hours (just like food) although their functional lifetime would be along the lines of one to two hours. Ultimately, the various components would either be digested or passed in the stool – so no, nothing would be re-used.

So far the scientists have developed an ingestible version of the battery, but they’re now ready to take the next step. “Once you have the battery technology down (which we do), this opens up a lot of different applications in actively powered edible electronics,” Bettinger told us. “We think there is a big future in edible devices because most patients are comfortable with swallowing a pill. The key is to make the materials safe and biocompatible, which we have done.”

A paper on the research was recently published in the Journal of Materials Chemistry B.