Though the chemotaxis sensing system of emph{Escherichia coli} is known to approach fundamental physical limits for biosensing, few attempts have been made to co-opt the system as the front end for a biohybrid sensor. We propose a biohybrid sensor that monitors chemotactic bacterial flagellar motor (BFM) rotation speed and direction to infer analyte concentration for a low-power, fast, and sensitive response. We present the design and fabrication of a four point impedimetric array that uses current injection electrodes to circumvent electrode polarization screening, enabling solution resistance monitoring within a four-micron by four-micron region. We also demonstrate dielectric microbead shaft encoders for the BFM, which bind to the BFM and encode rotation. When these two components are integrated by bringing the rotating shaft encoders in proximity to the microelectrode array, they will enable an electrochemical method for observing the BFM. Such an impedance-based biohybrid sensor obviates the need for a microscope and in principle may be multiplexed and scaled to large arrays of BFMs, enabling the development of deployable low-power and fast sensing systems that directly observe the BFM to infer analyte concentration.
Project end date: 01/29/19