A Ferrocene-Based Conjugated Oligoelectrolyte Catalyzes Bacterial Electrode Respiration

Abstract

For emerging bioelectronic technologies, charge-transfer processes remain rate limited by energy-level mismatching and poor contacts at biotic-abiotic interfaces. Direct chemical modification of these interfaces represents an underdeveloped approach for amplifying biocatalyzed current production. We present the synthesis and application of DSFO+, a redox-active molecule that is designed for membrane affinity and that catalytically couples to biological respiratory transmembrane electron transport, similarly to a heme-containing protein. DSFO+ was employed with three strains of Shewanella oneidensis MR-1 (an electrogenic wild-type and two non-electrogenic knockout mutants) and amplified anodic biocurrent in all strains without toxicity at a physiologically relevant redox potential. Of particular interest, DSFO+ increased metabolic efficiency and biological electron production, thus stimulating respiratory biocurrent production in non-electrogenic bacterial phenotypes. The overall effect is akin to a ‘‘protein prosthetic’’ electron transfer agent.