A Bioelectrochemical Crossbar Architecture Screening Platform (BiCASP) for Extracellular Electron Transfer

Electroactive microbes can be used as components in electrical devices to leverage their unique behavior for biotechnology, but they remain challenging to engineer because the bioelectrochemical systems (BES) used for characterization are low-throughput. To overcome this challenge, we describe the development of the Bioelectrochemical Crossbar Architecture Screening Platform (BiCASP), which allows for samples to be arrayed and characterized in individually addressable microwells. This device reliably reports on the current generated by electroactive bacteria on the minute time scale, decreasing the time for data acquisition by several orders of magnitude compared to conventional BES. Also, this device increased the throughput of screening engineered biological components in cells, quickly identifying mutants of the membrane protein wire MtrA in Shewanella oneidensis that retain the ability to support extracellular electron transfer (EET). BiCASP is expected to enable the design of new components for bioelectronics by supporting directed evolution of electroactive proteins.