A Papertronic, On‐Demand and Disposable Biobattery: Saliva‐Activated Electricity Generation from Lyophilized Exoelectrogens Preinoculated on Paper

Portable, on-demand micropower generation is provided by developing paper-based biobatteries that can deliver on-chip energy to the next generation of point-of-care (POC) diagnostic platforms. This work creates a low-cost, disposable, long shelf life and eco-friendly micropower source that can be easily integrated in paper-based POC devices and be readily activated by one drop of saliva, which is readily available in any challenging area. A high-performance, paper-based, bacteria-powered battery is created by building microbial fuel cells with inactive, lyophilized (or freeze-dried) exoelectrogenic cells, allowing for a long shelf life, which generates power within minutes of adding saliva. An oxygen-tight interface and engineered conductive paper reservoir achieve significant performance boosts from maximized microbial electron transfer efficiency. Exoelectrogenic bacteria preinoculated in the paper battery is freeze-dried for long-term storage (in this work, the bacteria cells are stored for up to four months) and can be readily rehydrated for on-demand power generation. Sixteen microbial fuel cells are incorporated on a single sheet of paper while all are connected in series with two electrical switches mounted on a paper circuit board, which produce more than enough electrical energy to power an on-chip, light-emitting diode.