Since 23 produced the strongest signal in the Ndh2competent strain, we conducted additional experiments to investigate this mediator's performance in a BES over longer time scales. Indeed, 23 stably mediated EET with Ndh2 for 5 days (120 Current density for all data is given as the change in current density from the time of quinone injection at t = 0 h. h), yielding incredibly stable, predictable current output over the full experiment (Fig. ). We conducted these experiments in comparison against the EET performance of 14, previously characterized to be a strong natural substrate for Ndh2 in BES experiments. While 14 produced a much greater current magnitude than 23, 14 also produced a high background signal in the Ndh2-deficient strain. Additionally, current generation for 14 reaches its maximum within a short period of time after mediator addition and current output continually drops over the course of the experiment under these experimental conditions. Neither 14 nor 23 generate current under abiotic conditions or in the presence of heat-killed cells, further confirming that EET signal is dependent on the presence of living cells (Fig. ). Comparison of normalized chronoamperometry traces for 14 and 23 (see experimental details), clearly illustrates the differences in current profile between the two compounds, specifically the stability of 23 (Fig. ). Taken together, these results highlight the potential of 23, 24, and 27 for use in biosensing applications, where stable current responses with low background are ideal properties. As such, these compounds have the potential to be used in wholecell L. plantarum bioelectronic devices, expanding the molecules available for EET-based biosensing.