Edible batteries

New batteries can be swallowed

Julia Korovsky, XXII CENTURY, based on ACS materials: Battery you can swallow could enable future indestructible medical devices

Scientists from Carnegie Mellon University have developed non–toxic edible batteries based on the pigment melanin. They presented the new development at the 252nd national meeting-exhibition of the American Chemical Society.

"People have been waiting for decades that one day we would have edible electronic devices for diagnosis and treatment," says Christopher Bettinger, one of the authors of the study. "But if you're going to use them on a daily basis, you need to think about the fact that they can be toxic." About twenty years ago, scientists developed an endoscopic capsule with a built-in video camera. After the patient swallows it, it passes through the gastrointestinal tract, takes pictures and is excreted from the body after a few hours. This method allows you to obtain images of areas of the gastrointestinal tract that are inaccessible to a traditional endoscope. If you use the capsule once, the risk that it will get stuck in the gastrointestinal tract is very small. However, if the patient swallows it often, the chances that something will go wrong increase.

This video capsule and some other implantable devices, in particular pacemakers, are powered by batteries containing toxic components. For low-power appliances that require frequent use, non-toxic degradable power supplies would be an ideal option. To minimize the damage from such batteries, scientists decided to use components of natural origin. Melanin pigments are found in the skin, hair and iris of the eye, they absorb ultraviolet rays and thereby protect tissues from radiation damage. In addition, they bind metal ions. "We thought it was essentially a battery," Bettinger explains.

Starting from this idea, scientists experimented with the design of the battery. They tried different electrode materials, iron and copper cations, and melanin as a positive or negative pole. "We found that they work," says Hang–Ah Park, a member of the scientific group. "The exact numbers depend on the configuration, but using a cathode of 600 milligrams of active melanin material, we can power 5 milliwatt devices for up to 18 hours."

A melanin battery is not as powerful as a lithium-ion battery, but it is enough to supply energy to a drug delivery device or sensor. In parallel, the scientific group is working on the creation of edible batteries from other biomaterials, in particular, pectin. 

In the future, the researchers promise to create materials that will safely deliver the battery to the stomach.

Melanins are amorphous dark brown and black pigments found in the hair, skin, feathers and retina of vertebrates, insects and some marine invertebrates, as well as in plants. Increased formation and deposition of melanins in the skin occurs under the influence of irradiation with sunlight and UV rays, which causes the appearance of sunburn, the formation of freckles, etc. Melanins have the properties of stable radicals and participate in electron transfer reactions. This is associated with their protective functions against UV radiation and ionizing radiation

Portal "Eternal youth" http://vechnayamolodost.ru  30.08.2016