Enhancement of Electricity Production of Microbial Fuel Cells by Using DNA Nanostructures as Electron Mediator Carriers
Shuo Han, Krishna Thapa, Wenyan Liu, David Westenberg, Risheng Wang
Abstract
Microbial fuel cells (MFCs) are recognized as eco-friendly technology to convert chemical energy from waste into electricity by biocatalytic microorganisms and biomass as fuel feedstocks. Here, a three-dimensional DNA origami nanostructure serving as electron mediator-methylene blue (MB) carriers was first employed to enhance the electron production and transfer in the anode compartment of Escherichia coli system-based MFCs. By loading MB molecules on DNA origami nanostructures, the MFC with the MB/DNA origami-modified carbon felt (CF) electrode showed the highest voltage production (64 mV) and power density (5.78 mW/m2) compared to bare CF and MB-modified CF electrodes. The enhanced MFC performance was attributed to the larger interface area of DNA origami-assisted MB loading and a biocompatible bacterial growth environment on the anode, which led to E. coli adhesion and fast electron transfer. Furthermore, the MFC with MB/DNA origami modifications could stably operate for three cycles (20 days) with constant voltage discharge without further addition of media. These results show that DNA origami is a promising material serving as an electron mediator carrier for sustainable energy systems, which could get over the drawbacks of carrier-free MFCs, such as short lifetime, continuously adding supplies, and toxicity to both the microorganisms and the natural environment.