Good enough to eat

Christopher Bettinger, Carnegie Mellon University is developing an edible battery made with melanin and dissolvable materials.

At a press conference organised by the American Chemical Society, Bettinger discussed polymers as they apply to batteries for ingestible medical devices. It’s a far cry from the advice we’ve been given outlining how dangerous batteries are if ingested but these are a different type of product altogether and may one day aid diagnosis and treatment.

Made with melanin pigments which is naturally found in skin, hair and eyes, this substance protects the body from damage by absorbing UV light to see off free radicals.

Covering the story, Science Daily wrote: “While he doesn't have to worry about longevity, toxicity is an issue. To minimise the potential harm of future ingestible devices, Bettinger's team at Carnegie Mellon University (CMU) decided to turn to melanins and other naturally occurring compounds. In our skin, hair and eyes, melanins absorb ultraviolet light to quench free radicals and protect us from damage. They also happen to bind and unbind metallic ions.”

Recognising this as a type of battery Bettinger  and his researchers “experimented with battery designs that use melanin pigments at either the positive or negative terminals; various electrode materials such as manganese oxide and sodium titanium phosphate; and cations such as copper and iron that the body uses for normal functioning”.

Compared to lithium-ion batteries, the capacity of Bettinger’s batteries are low. However, they would be strong enough to drive a biomedical device such as an ingestible drug delivery device.