DNA ‘Velcro’ to Interface Electron Transfer-Competent Cells with Electrodes

Abstract

Microbial fuel cells offer promising technology for clean energy. However, challenges remain with the broad implementation of these systems, especially due to inconsistent interactions between microbes and electrode surfaces. A key challenge is to maintain specificity in the placement of cells while facilitating electron transfer between the cells and the surface. DNA can both self-recognize and act as a molecular wire. By applying the inherent specificity of DNA hybridization, we have used DNA as ‘velcro’ to control the interactions between cells and electroactive surfaces. DNA-modified electrodes were used to capture and quantify non-adherent cells, including the electron transfer-proficient organism Shewanella oneidensis. When immobilized on electrodes using this biological ‘velcro,’ Shewanella preserve their electron transfer capabilities prior to biofilm formation. We attribute this ability, at least in part, to the conductivity of DNA. Our DNA-based technique to interface cells with electrodes has significantly improved the ease of fabrication and generation of current from microbe-modified electrodes.