Interface of Electrogenic Bacteria and Reduced Graphene Oxide: Energetics and Electron Transport

A synergistic, nanoscale electrical interface with the membranes of exoelectrogenic microbes will have a transformative impact on biological cell-based electronic devices. Here, we report that a conformal graphenic interface on a biocatalytic Geobacter sulfurreducens membrane results in quantum-capacitance-induced n-doping in reduced graphene oxide (rGO) that further enhances electron shuttling from the membrane to improve electron harvesting from the electrogenic organism. The quantum coupling of rGO with the connected protein-membrane channels leads to an additional electron density of 3.91 × 1012 cm–2 and an increase in the in-plane phonon vibration energies (G) of rGO by ∼5 cm–1. This n-doping enhances the electron-transfer rate from the cell membrane into the rGO via a net driving potential of 158 meV with a 3-fold increase in power density. The synergistic electron harvesting and conformal membrane interfacing of flexible two-dimensional (2D) nanomaterials can lead to an evolution in the design of microbe circuitry to power stand-alone nanodevices.