(360c) A Comprehensive Strategy for Whole-Cell Electrochemical Biosensor Design: From Sensor Biomining to Deployable Devices

The ability to detect contaminants, soil nutrients, and other relevant molecules in the environment is crucial to protect human and environmental health. However, established measurement techniques for these analytes are typically expensive, laborious and slow. Alternative sensing technologies, namely whole-cell electrochemical biosensors, are increasingly popular alternatives. These technologies use microbes to detect analytes, harnessing the array of naturally-evolved sensor systems in living cells. These microbes then interface with electrodes, producing electrical signals that can be interpreted by digital devices. These sensors boast high specificity and low cost, and we have integrated the development of these sensors into a comprehensive and generalizable workflow. We have streamlined the receptor biomining process through the development of a bioinformatic tool and guiding principles for selecting and expressing sensor proteins. We have additionally developed a quantitative model of gene circuit performance in the platform sensor strain Shewanella oneidensis, enabling a priori design of electroactive gene circuits with an arbitrary receptor protein. Finally, we have invented a novel device configuration which reduces cost by an order of magnitude while eliminating requirements for specialized equipment. We have used this workflow to develop biosensors for a suite of soil nutrients and environmental contaminants, demonstrating the broad applicability of our strategy.