(618b) Multichannel Bioelectronic Sensing Using Engineered Escherichia coli

To advance environmental health and hazard detection, researchers have developed whole-cell bioelectronic sensors by engineering extracellular electron transfer (EET) to be dependent on an analyte. However, these sensors regulate a single electron transfer pathway as an electrochemical channel, limiting the sensing information to a single analyte. We have developed a multichannel sensor where different chemicals regulate distinct EET pathways within a single Escherichia coli cell. One channel utilizes the flavin synthesis pathway from Bacillus subtilis and is controlled by a cadmium-responsive promoter. A second channel, the Mtr pathway from Shewanella oneidensis, is controlled by an arsenite-responsive promoter through activation of cytochrome CymA expression. Further, we exploit the differing redox potentials of the two EET pathways to develop a redox-potential-dependent algorithm that efficiently converts electrical signals into 2-bit binary output. The algorithm enables the detection of heavy metal at EPA limits with a concentration-dependent response. When exploring our bioelectronic sensor in environmental water samples over the long term, a notable threefold decrease in current values was observed. However, the algorithm still allows for effective and accurate signal differentiation across analyte conditions. Thus, our multichannel bioelectronic sensor advances the field of simultaneous detection of different chemicals in a single cell, significantly expanding information transmission from EET and helping to safeguard human and environmental health.