Researchers are trying to find a safe, non-toxic way to power electric implants like pacemakers by looking at electric eels, according to Nature. Why it matters: If the prototype can be successfully developed, it could be safer for the body because it wouldn't be as potentially toxic as traditional batteries, and could eventually run on bodily fluids, per Nature. It's also flexible, transparent, and runs on a solution of salt and water.How it works: The fish (which are not true eels) have specialized cells electrocytes all along the length of their bodies. They change the electrocyte's conductivity varying the salt and mineral concentrations in the cells. This causes the cells to create a flow of charge-carrying ions, producing electricity. Each cell only produces a small charge, but stacked together they can produce up to 600 volts of electricity to locate and stun prey.

Thomas Schroeder, a chemical engineer at the University of Michigan, and his team made similar models of electrocytes using four different hydrogels made of polyacrylamide and water. They combined 2,500 units to produce 110 volts -- enough to potentially power "ultra-low-power devices, including some cardiac pacemakers," per Nature.