Localized electrical stimulation triggers cell-type-specific proliferation in biofilms

Biological systems ranging from bacteria to mammals utilize electrochemical signaling. Although artificial electrochemical signals have been utilized to characterize neural tissue responses, the effects of such stimuli on non-neural systems remain unclear. To pursue this question, we developed an experimental platform that combines a microfluidic chip with a multielectrode array (MiCMA) to enable localized electrochemical stimulation of bacterial biofilms. The device also allows for the simultaneous measurement of the physiological response within the biofilm with single-cell resolution. We find that the stimulation of an electrode locally changes the ratio of the two major cell types comprising Bacillus subtilis biofilms, namely motile and extracellular-matrix-producing cells. Specifically, stimulation promotes the proliferation of motile cells but not matrix cells, even though these two cell types are genetically identical and reside in the same microenvironment. Our work thus reveals that an electronic interface can selectively target bacterial cell types, enabling the control of biofilm composition and development. [Display omitted] •Introducing a device capable of localized electrical stimulation within a biofilm•Stimulation increases the ratio of motile to matrix-producing cells•Electrical stimulation selectively promotes motile cell proliferation•Cell-type-specific response enables bioelectric control of biofilm organization We developed a device to electrically stimulate a growing bacterial biofilm. Localized electric stimulation results in the proliferation of motile cells over matrix-producing cells, despite the two cell types being genetically identical and sharing a local environment. This cell-type-specific proliferation suggests that electrical stimulation can be used to control biofilm development and suggests parallels with bioelectrical signaling during embryogenesis.