8. Biocompatible battery harvests its energy from the bodyEngineers at the University of Maryland have created a biocompatible battery that uses the same ion-based electrical energy that is present in all living things – including humans.
Sodium, potassium and other electrolytes are constantly flowing through our bodies and creating electrical signals. The electrical signals are what power the brain and help control the rhythm of the heart.
Traditional batteries produce power by using a flow of moving electrons. Those batteries move positive ions from one end of the battery to the other. The University of Maryland battery does the opposite by moving electrons around the device to deliver a flow of ions. The engineers claim that this is the first time that an ionic current-generating battery has been made.
Living cells use ionic currents that flow at a low voltage. Electronic-to-ionic patches would create a current that is too high to run a brain or a muscle. The engineers suggest that the patches could be eliminated by using ionic current batteries that could be run at any voltage.
The UMD battery also uses grass to store its energy. The engineers soaked blades of Kentucky bluegrass in a lithium salt solution. The channels that move nutrients through the grass blades held the solution.
When testing the battery, the researchers found that the ionic current flowed by touching the ends of the battery to the end of a lithium-soaked cotton string and a small amount of blue-dyed copper ions in the middle. Caught up in the ionic current, The copper moved along the string to the negatively charged pole when it was in the ionic current.
“The battery could be used to develop medical devices for the disabled, or for more efficient drug and gene delivery tools in both research and clinical settings, as a way to more precisely treat cancers and other medical diseases,” said Jianhua Zhang, a staff scientist at the National Institute of Diabetes and Digestive and Kidney Diseases, in a press release. “Potential applications might include the development of the next generation of devices to micro-manipulate neuronal activities and interactions that can prevent and/or treat such medical problems as Alzheimer’s disease and depression.”