Redox-active conducting polymers modulate Salmonella biofilm formation by controlling availability of electron acceptors

Abstract

Biofouling is a major problem caused by bacteria colonizing abiotic surfaces, such as medical devices. Biofilms are formed as the bacterial metabolism adapts to an attached growth state. We studied whether bacterial metabolism, hence biofilm formation, can be modulated in electrochemically active surfaces using the conducting conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT). We fabricated composites of PEDOT doped with either heparin, dodecyl benzene sulfonate or chloride, and identified the fabrication parameters so that the electrochemical redox state is the main distinct factor influencing biofilm growth. PEDOT surfaces fitted into a custom-designed culturing device allowed for redox switching in Salmonella cultures, leading to oxidized or reduced electrodes. Similarly large biofilm growth was found on the oxidized anodes and on conventional polyester. In contrast, biofilm was significantly decreased (52–58%) on the reduced cathodes. Quantification of electrochromism in unswitched conducting polymer surfaces revealed a bacteria-driven electrochemical reduction of PEDOT. As a result, unswitched PEDOT acquired an analogous electrochemical state to the externally reduced cathode, explaining the similarly decreased biofilm growth on reduced cathodes and unswitched surfaces. Collectively, our findings reveal two opposing effects affecting biofilm formation. While the oxidized PEDOT anode constitutes a renewable electron sink that promotes biofilm growth, reduction of PEDOT by a power source or by bacteria largely suppresses biofilm formation. Modulating bacterial metabolism using the redox state of electroactive surfaces constitutes an unexplored method with applications spanning from antifouling coatings and microbial fuel cells to the study of the role of bacterial respiration during infection.

Biohybrid Conjugated Polymer Materials for Augmenting Energy Conversion of Bioelectrochemical Systems

“…[38] Richter-Dahlfors et al provent hat controlling the redox state of poly(3,4-ethylenedioxythiophene) (PEDOT)w as capable of regulating biofilm formation. [39] Besides,t he nanostructured polyaniline and polypyrrole have also been shown to contribute to the current output of MFCs. [40] In this way,W ang and co-workersconstructed polythiophene derivatives PMNT/S.…”

Device Fabrication Based on Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Conducting Polymers and Related Conjugated Organic Materials

“…The fouling of surfaces, which gives rise to the formation of undesirable materials on the equipment surfaces, is a costly problem. Fouling often worsens equipment performance and impacts many technologies including membranes, biomedical devices, marine ships, and infrastructures . The CPs are of extreme importance in applications such as neural recording electrodes, implantable electronic medical devices (IEMDs), and electrically conductive membrane, that require both fouling resistance and conductivity at the same time, while the majority of fouling resistance polymer coatings are insulators.…”

Conjugated Oligo- and Polymers for Bacterial Sensing

“…The most well-known CP counter anions are tosylate (Tos), poly(styrenesulfonate) (PSS), and dodecyl benzene sulfonate (DBS). Several other small and biologically relevant anions have also been used, such as heparin, DNA and dexamethasone (Herland et al, 2011; Gomez-Carretero et al, 2017; Shah et al, 2018).…”

“…Successful modulation of the formation of Salmonella biofilm has been demonstrated using electropolymerized PEDOT doped with heparin, DBS, or chloride (Gomez-Carretero et al, 2017). Fabrication of polymer surfaces was performed under conditions that maintained comparable charge storage capacity and hydrophobicity irrespective of counter ion.…”