Towards patterned bioelectronics: facilitated immobilization of exoelectrogenic Escherichia coli with heterologous pili

Summary Biosensors detect signals using biological sensing components such as redox enzymes and biological cells. Although cellular versatility can be beneficial for different applications, limited stability and efficiency in signal transduction at electrode surfaces represent a challenge. Recent studies have shown that the Mtr electron conduit from Shewanella oneidensis MR‐1 can be produced in Escherichia coli to generate an exoelectrogenic model system with well‐characterized genetic tools. However, means to specifically immobilize this organism at solid substrates as electroactive biofilms have not been tested previously. Here, we show that mannose‐binding Fim pili can be produced in exoelectrogenic E. coli and can be used to selectively attach cells to a mannose‐coated material. Importantly, cells expressing fim genes retained current production by the heterologous Mtr electron conduit. Our results demonstrate the versatility of the exoelectrogenic E. coli system and motivate future work that aims to produce patterned biofilms for bioelectronic devices that can respond to various biochemical signals. Selective immobilization of exoelectrogenic Escherichia coli at mannose‐coated surfaces was achieved by coproduction of E. coli Fim pili and the Shewanella oneidensis MR‐1 Mtr electron transfer pathway (METP). On soluble electron acceptors, Fim pili production did not alter the functionality of the METP and vice versa. These findings motivate further research efforts to exploit the full potential of the exoelectrogenic E. coli platform for biofilm patterning in bioelectronics and biosensor applications.