Session: Current Topics in Biological Chemistry:

Microbial fuel cells (MFCs) are biological fuel cells that can produce electricity using electrons produced during bacterial metabolism. Electrons generated are transported to the electrode either directly by microbes through cytochromes and nanowire structures or in an indirect way using redox-active electron mediators. Escherichia coli has often used bacteria in MFC and reported to have good performance, however, it uses the indirect method for electron transfer. It is found that E. coli can use Methylene Blue (MB) as an electron mediator bridge which carries the electrons to the electrode surface. Even though the electron mediators show good ability to increase the current production in MFCs, the low solubility, high toxicity, and difficulty in accessing the bacterial electron source, are still major bottlenecks in the practical application of MFCs. MB is one of the most promising electron mediators because of its good solubility and redox characteristics. But its electron transfer efficiency and biological incompatibility could still be improved. DNA origami, with its ability to self-assemble into programmable multidimensional structures, have shown promise as a carrier for small organic molecules like proteins and drugs and poses natural biocompatibility. Since MB can couple DNA bases through π-π-stacking, in this study MB were immobilized on 3D triangle DNA origami, and the effect of DNA origami as electron mediator carriers in MFC is observed. The performance of MFCs with MB and MB/DNA origami complex treated electrodes were compared with controls using cyclic voltammetry, power density, and voltage output capability. Our results suggest that the DNA origami was effective in increasing the electron transfer efficiency and could be a very useful mechanism for scaling up the MFC capacity and application.

Dr. Wenyan Liu

Research Assistant Professor, Missouri University of Science and Technology

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