Fossil fuels are old-school. A newly identified renewable energy source is safe, portable – and free. It’s called spit.
Researchers from Pennsylvania State University and King Abdullah University of Science and Technology in Saudi Arabia have used saliva to power a tiny microbial fuel cell that generates nearly 1 microwatt.
Bacteria in the fuel cell break down glucose and other organic components of saliva to release energy. A current then runs between an air cathode and an anode made of graphene, an extremely thin carbon material. (The Penn State researcher, Bruce Logan, won a 2005 Popular Mechanics Breakthrough Award for earlier work on microbial fuel cells.) The technology could be used to power lab-on-a-chip diagnostic devices to allow women to predict ovulation or to help diabetics track their glucose levels.