Researchers in Pennsylvania are developing non-toxic, edible batteries, which could one day power ingestible devices for diagnosing and treating disease.
One of the highlights of the 9,000 science presentations at the recent 252nd National Meeting & Exposition of the American Chemical Society (ACS), held at the Pennsylvania Convention Center in August, came from within the same state. A team at Carnegie Mellon University (CMU) in Pittsburgh have created a tiny, edible battery that can power ingestible sensing or diagnostic devices, while being non-toxic to the body. The batteries are made with melanin pigments, naturally found in the skin, hair and eyes.
The Bettinger Group at Carnegie Mellon University is a leading innovator in ‘edible electronics’. Researchers are exploring the use of polymer synthesis, materials science, and microfabrication in a wide range of biomedical applications including advanced medical devices, regenerative medicine, bio-interfaces, and drug delivery.
Christopher Bettinger, Ph.D, says: “For decades, people have been envisioning that one day, we would have edible electronic devices to diagnose or treat disease. But if you want to take a device every day, you have to think about toxicity issues. That’s when we have to think about biologically derived materials. The beauty is that by definition an ingestible, degradable device is in the body for no longer than 20 hours or so.”
Melanin in our skin, hair and eyes absorbs ultraviolet light to quench free radicals and protect us from damage. They also happen to bind and unbind metallic ions. “We thought, this is basically a battery,” Bettinger says. Researchers experimented with battery designs that use melanin pigments at either the positive or negative terminals, with a second substance, such as the mineral manganese oxide or the benign metal magnesium, forming the second terminal. The aqueous fluid in the GI tract comprises the electrolyte.
Although the capacity of a melanin battery is low relative to lithium-ion, it would be high enough to power an ingestible drug-delivery or sensing device. Hang-Ah Park, Ph.D., a post-doctoral researcher at CMU, notes: “The exact numbers depend on the configuration, but as an example, we can power a 5 milliWatt device for up to 18 hours using 600 milligrams of active melanin material as a cathode.”
The team is currently looking for industry partners to help bring the melanin-based battery to market. In the meantime, it’s also working on making edible batteries using other biomaterials, such as pectin – a compound found in plants.
Featured image: Researchers believe that the edible battery could be used with numerous ingestible devices (Credit: Stephanie Strasburg)
(via ACS and New Atlas)