Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7140394 | Sensors and Actuators B: Chemical | 2018 | 16 Pages |
Abstract
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 60â¯Î¼m-sized electrode arrays (MEAs) to characterize the structure of biofilms formed by wild type (WT) Escherichia coli TG1 and the isogenic ÎcsgD, ÎcsgB and ÎbcsA mutants. At 24â¯h of growth, the interfacial resistance at 2â¯Hz increased by 3.4% and 0.3% for the curli producing strains (WT and ÎbcsA), yet it decreased by 5.7% and 4% for the curli non-producing strains (ÎcsgD and ÎcsgB). The imaginary impedance at 2â¯Hz decreased for all the strains by 7.2%, 6.9%, 5.1% and 2.5% (WT, ÎbcsA, ÎcsgB and ÎcsgD, 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 10â¯h, and was characterized by an increase in the interfacial resistance of up to 6% for the WT, 5.5% for ÎcsgD, 3.5% for ÎcsgB and 5% for ÎbcsA, 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.
Keywords
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Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Erkuden Goikoetxea, Denis Routkevitch, Ami de Weerdt, Jordan J. Green, Hans Steenackers, Dries Braeken,