3D Printing of Living MFC Anode

3D printing helps to provide further control on electrode design. By using 3D printing to tune the geometry, porosity and dimensions of the structure, mass transport to functional microbes or sites in the structure can be improved. By embedding living microbes directly into the ink we can create 3D printed structures to help harness the activity of microbes and use them in functional devices. Here we demonstrate the incorporation of the living bacteria Shewanella Oneidensis MR-1 (S. Oneidensis MR-1) directly into an ink used for creating 3D printed structures. By incorporating S. Oneidensis MR-1 into a sodium alginate-cellulose ink we showed that S. Oneidensis MR-1 survives the 3D printing process through the prominent degradation of methyl orange azo dye from the surrounding solution in the presence of the living 3D printed structure. The viability was further confirmed using confocal microscopy. By incorporating carbon black into this ink we further demonstrate the direct printing of a living microbial fuel cell (MFC) anode. Electrochemical measurements showed there was good charge transfer between the S. Oneidensis MR-1 and the electrode surface. To our knowledge, this is the first report on implementing 3D printed bacteria structure as a living electrode for an MFC system. The capability of printing living and functional 3D bacterial structure could open up new possibilities in design and fabrication of microbial devices as well as fundamental research on the interaction between different bacterial strains, electrode materials, and surrounding environments.