Deciphering Single-Bacterium Adhesion Behavior Modulated by Extracellular Electron Transfer

Abstract

For bacterial adhesion and biofilm formation, a thorough understanding of the mechanism and effective modulating is lacking due to the complex extracellular electron transfer (EET) at bacteria-surface interfaces. Here, we explore the adhesion behavior of a model electroactive bacteria under various metabolic conditions by an integrated electrochemical single-cell force microscopy system. A nonlinear model between bacterial adhesion force and electric field intensity is established, which provides a theoretical foundation for precise tuning of bacterial adhesion strength by the surface potential and the direction and flux of electron flow. In particular, based on quantitative analyses with equivalent charge distribution modeling and wormlike chain numerical simulations, it is demonstrated that the chain conformation and unfolding events of outer membrane appendages are dominantly impacted by the dynamic bacterial EET processes. This reveals how the anisotropy of bacterial conductive structure can translate into the desired adhesion behavior in different scenarios.

Efficient CO2conversion by biocompatible N-doped carbon nanosheets coupled withRalstonia eutropha: synergistic interactions between microbial and inorganic catalysts

“…The bacterial adhesion to the electrode is mainly affected by the electrostatic force. 50 Since the pH is greater than the isoelectric point of bacteria ( pH = 3-4) under neutral conditions, R. eutropha is electronegative and binds more tightly to positively charged surfaces. 21,50 Thus, electron localization function (ELF) calculations were conducted to reveal the charge distribution of NC-8-1000.…”

“…50 Since the pH is greater than the isoelectric point of bacteria ( pH = 3-4) under neutral conditions, R. eutropha is electronegative and binds more tightly to positively charged surfaces. 21,50 Thus, electron localization function (ELF) calculations were conducted to reveal the charge distribution of NC-8-1000. The presence of a region with ELF = 1 around N atoms indicated an electron build-up around N atoms in NC-8-1000 compared to the non-nitrogen-doped samples, especially for pyridinic N (Fig.…”

Periodic polarization duty cycle tunes performance and adhesion of anodic electroactive biofilms

“…It is impossible to conclude yet on the cause(s) leading to those detachments. Several non-exclusive causes could be proposed: (i) the high current density reached; (ii) the longer period fraction at which EAB50% is under OCP i.e., at low electrode potentials (quickly stabilizing ~ − 0.45 V vs. Ag/AgCl [24]), indeed lower potentials have been shown to decrease the adhesion of single cells of S. oneidensis MR-1, a model electroactive bacterium [36], and adhesion of mammalian cells dramatically decreased when an underlying electrode was poised below its zero charge potential (i.e. with a negatively charged surface), at which point previously adhering cells could even detach [37]; (iii) periodic local pH variations at the electrode/EAB interface following the cycle of current spike (reconnection) and open circuit ─ though the medium was highly buffered; and (iv) a higher shear-stress imposed on EAB50% which develop an uneven morphology (mushroom-like structure) while EABs grown under continuous polarization are flat, as shown in our previous study [24].…”

In Situ Probing of the Intrinsic Adhesion Strength of Single Anaerobic Microbial Cells

“…For instance, the adhesion between anaerobic bacteria and archaea decides the biofilm formation of anaerobic microbes, structural maintenance for gut microbiota, and syntrophic collaboration to convert carbohydrates to methane . Because of the rich heterogeneity and complexity in surface structure, , there is significant interest in quantifying the intra- and interadhesion strength of anaerobic microbes at the single-cell level.…”