Temporal-Spatial Control of Potassium Ions Delivery via Bioelectronics Modulates Membrane Voltage and Growth Dynamics in Bacteria Biofilms

Bioelectrical signaling, or bioelectricity, is crucial in regulating cellular behavior in biological systems. This signaling, involving ion fluxes and changes in membrane potential (V_mem), is particularly important in the growth of bacterial biofilms. Current microfluidic-based methods for studying bacterial colonies are limited in achieving spatiotemporal control over ionic fluxes due to constant flow within the system. To address this limitation, we have developed an innovative platform that integrates biofilm growth with bioelectronic ion pumps that enable targeted delivery of potassium (K⁺) ions, allowing for controlled manipulation of local potassium concentration. With deterministic delivery of K⁺, we adjust the concentration of extracellular K⁺ and affect both the biofilm membrane voltage and growth dynamics. In our study, we observe significant changes in V_mem and coordination within the biofilms. Changes in V_mem are influenced by K⁺ level where higher K⁺ concentration change results in more pronounced modulation of the V_mem. Furthermore, we investigate the impacts of spatially controlled K⁺ delivery on bacterial biofilm growth patterns and dynamics. The elevated K⁺ concentrations correlating with larger growth rates enable us to direct growth in desired directions and induce anisotropy in the biofilm. These findings demonstrate that localized K⁺ delivery is highly effective in controlling biofilm expansion in a spatially targeted manner. These observations offer insights into the mechanisms underlying bacterial signaling and growth and suggest potential applications of bioelectronics in bioengineering, synthetic biology, and regenerative medicine, where precise control over cellular signaling and subsequent tissue growth is required.