When you think of batteries, what comes to mind? Lead? Lithium?
At a minimum, the chemistry of batteries seems to involve stuff you don't want to eat. But what if doctors could use batteries to power small cameras or ingestible drug delivery devices?
Today, some diagnostics do involve patients swallowing small battery-powered cameras, with the intent that these will pass through without harm. But for frequent use, the risks of such devices outweighs the benefits. Non-toxic batteries that would dissolve if lost in the body could solve that problem. This goal drives the scientists asking themselves, "how can a battery work without the toxic metals so often associated with electronics and e-waste?"
One answer appears to involve melanin. The pigment that darkens our skin to protect us from the ultra-violet rays of the sun also interacts with the electrons in metals, making them good candidates for the edible battery. By using metals such as copper or iron that are also naturally present in our bodies, researchers have succeeded to create working batteries.
Hang-Ah Park, Ph.D., a post-doctoral researcher on the edible battery team, reflects,
"We found basically that they work. 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 amount of power and duration of battery life clearly won't compete with lead or lithium batteries any time soon - but as a niche product for biomedical devices, the technology shows promise. Even if they are not in immediate competition to power our cell phones or video games, what scientists learn about using natural materials will advance our understanding of both the chemistry of our bodies and the opportunities for less toxic products.
You can join a press conference on the edible battery at 1:30 p.m. Eastern time today (August 23, 2016) to learn more.
Edible batteries, along with cleaner cars, tastier foods, and other advances feature among the topics as members of the American Chemical Society (ACS) gather this week in Philadelphia for the 252nd annual conference (follow the ACS tweets).