In addition to utilization of natural TEAs, many organisms that perform EET can also use an anode within a bioelectrical system (BES) as a TEA, thereby generating a current. The detectable current is an electrical feature that has been leveraged for biosensing applications as it can report on a microorganism's local environment. For example, engineered bioelectronic signaling systems have successfully been designed to sense biologically-relevant small molecules, including pyocyanin and riboflavin. An engineered two microbe system has been designed to detect and degrade organophosphate pesticides, where modified Shewanella oneidensis detects degradation products of the pesticides that are produced by Escherichia coli. However, the readout is slow (requires translation), insensitive, and lacks selectivity. Alternatively, E. coli has been engineered so that an analyte triggers a conformational change in one of the proteins in a synthetic EET pathway, allowing an endocrine disruptor to be detected in minutes. However, these sensors rely on bespoke engineered electron transfer pathways and proteins that must be reengineered for each analyte. Advancing our understanding of mediated EET has the potential to overcome some of these challenges.