Disposable, paper-based electronics – also known as “papertronics” – is fast-emerging in the diagnostic sensor arena. Because paper is low-cost, readily available, highly portable and biodegradable, it’s the ideal substrate for use in remote areas where resources are limited. Now engineers have developed a paper-based battery, using bacteria, which could provide the necessary power source for a variety of papertronics devices.
The new battery is constructed in layers – including an anode, cathode and proton exchange membrane (PEM) – on a piece of chromatography paper. Cellular respiration within a few drops of bacteria-filled liquid generates the power. By folding and stacking layers in different ways, the power and current outputs can be improved significantly. Using six batteries in three parallel series, the researchers were able to generate over 21 microwatts at 125 microamps. In a six-by-six configuration, the observed output was nearly 45 microwatts at 105 microamps. Either way, the system generates adequate power to run biosensors for monitoring glucose levels or detecting pathogens. And because the microorganisms can harvest electricity from any biodegradable material, the battery could be run on dirty wastewater, which is readily available even in underdeveloped areas.