Impedimetric fingerprinting and structural analysis of isogenic E. coli biofilms using multielectrode arrays

© 2018 Elsevier B.V. Microbial biofilm contamination is an ubiquitous and persistent problem in industry and clinics. The structure of the biofilm, its extracellular matrix and its formation process are very complex. At present, there are only limited options to investigate biofilms outside the lab, as most in situ techniques lack sensitivity and resolution. Impedance-based sensors provide a fast, label-free and sensitive manner to characterize biofilms, although mainly large electrodes have been used so far. Here, we used 60 μm-sized electrode arrays (MEAs) to characterize the structure of biofilms formed by wild type (WT) Escherichia coli TG1 and the isogenic ΔcsgD, ΔcsgB and ΔbcsA mutants. At 24 h of growth, the interfacial resistance at 2 Hz increased by 3.4% and 0.3% for the curli producing strains (WT and ΔbcsA), yet it decreased by 5.7% and 4% for the curli non-producing strains (ΔcsgD and ΔcsgB). The imaginary impedance at 2 Hz decreased for all the strains by 7.2%, 6.9%, 5.1% and 2.5% (WT, ΔbcsA, ΔcsgB and ΔcsgD, respectively). Interestingly, the spatial variation of impedance within each biofilm, resulting from physiological and structural heterogeneity, was significantly different for each biofilm and most pronounced in the WT. Depending on the strain, the biofilm attachment phase lasted between 6 and 10 h, and was characterized by an increase in the interfacial resistance of up to 6% for the WT, 5.5% for ΔcsgD, 3.5% for ΔcsgB and 5% for ΔbcsA, as opposed to the decrease in medium resistance observed during the maturation phase. Overall, impedance-based MEA assays proved effective to differentiate between biofilms with varying structure, detect spatial diversity and explain biofilm life-cycle in terms of attachment and maturation.

Publication year:2018

BOF-keylabel:yes

IOF-keylabel:yes

BOF-publication weight:6

CSS-citation score:1

Authors:International

Authors from:Government, Higher Education

Accessibility:Open