Flexible Platform for In Situ Impedimetric Detection and Bioelectric Effect Treatment of Escherichia Coli Biofilms

Goal: This paper reports a platform for real-time monitoring and treatment of biofilm formation on three-dimensional biomedical device surfaces. Methods: We utilize a flexible platform consisting of gold interdigitated electrodes patterned on a polyimide substrate. The device was integrated onto the interior of a urinary catheter and characterization was performed in a custom-developed flow system. Biofilm growth was monitored via impedance change at 100 Hz ac with a 50 mV signal amplitude. Results: A 30% impedance decrease over 24 h corresponded to Escherichia coli biofilm formation. The platform also enabled removal of the biofilm through the bioelectric effect; a low concentration of antibiotic combined with the applied ac voltage signal led to a synergistic reduction in biofilm resulting in a 12% increase in impedance. Biomass characterization via crystal violet staining confirmed that the impedance detection results correlate with changes in the amount of biofilm biomass on the sensor. We also demonstrated integration with a chip-based impedance converter to enable miniaturization and allow in situ wireless implementation. A 5% impedance decrease measured with the impedance converter corresponded to biofilm growth, replicating the trend measured with the potentiostat. Conclusion: This platform represents a promising solution for biofilm infection management in diverse vulnerable environments. Significance: Biofilms are the dominant mode of growth for microorganisms, where bacterial cells colonize hydrated surfaces and lead to recurring infections. Due to the inaccessible nature of the environments where biofilms grow and their increased tolerance of antimicrobials, identification, and removal on medical devices poses a challenge.