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Optimierung und Lokalisation elektroaktiver Biofilme mittels magnetischer Nanopartikel
Citation Link: https://doi.org/10.15480/882.17247
Publikationstyp
Doctoral Thesis
Date Issued
2026
Sprache
German
Author(s)
Wurst, René
Advisor
Referee
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2025-11-21
Institute
TORE-DOI
Citation
Technische Universität Hamburg (2026)
In bioelectrochemical systems (BES), the formation and architecture of biofilms are of crucial importance, especially in the context of flow-through applications. The interface between electroactive microorganisms and the electrode surface plays a pivotal role in determining the available surface area, which in turn influences energy generation. This is particularly relevant in organisms that form only weak anodic biofilms. To address this limitation, nanoparticles (NPs) with a magnetic iron core and a conductive, hydrophobic carbon shell were utilized as building blocks to
create conductive, magnetic micropillars on the anode surface. The formation of this dynamic three-dimensional electrode architecture was monitored and quantified in situ using optical coherence tomography (OCT). Cyclic voltammetry revealed that the assembled three-dimensional anode extensions were electrically conductive and increased the available electroactive surface area. The NPs functioned as controllable carriers for the electroactive model organisms Shewanella oneidensis and Geobacter sulfurreducens, resulting in a fivefold increase in steady-state current density for S. oneidensis. This increase was further enhanced up to 22-fold when combined with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) aggregates. In the case of G. sulfurreducens, the steady-state current density was not increased but was reached four times faster. Additionally, the biosynthesis of magnetic FeS-NPs by S. oneidensis was investigated to generate hybrid biofilms with optimized properties. The biogenic particles exhibited both magnetic and electroactive properties, enabling improved electrical coupling to the electrode without inducing cytotoxic effects. This study proposes a method for expanding the electrode surface in existing BES. This method is controllable, scalable, and easily applicable. It involves applying a magnetic field and adding conductive magnetic NPs. These findings are likely transferable to other electroactive microorganisms as well.
create conductive, magnetic micropillars on the anode surface. The formation of this dynamic three-dimensional electrode architecture was monitored and quantified in situ using optical coherence tomography (OCT). Cyclic voltammetry revealed that the assembled three-dimensional anode extensions were electrically conductive and increased the available electroactive surface area. The NPs functioned as controllable carriers for the electroactive model organisms Shewanella oneidensis and Geobacter sulfurreducens, resulting in a fivefold increase in steady-state current density for S. oneidensis. This increase was further enhanced up to 22-fold when combined with poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) aggregates. In the case of G. sulfurreducens, the steady-state current density was not increased but was reached four times faster. Additionally, the biosynthesis of magnetic FeS-NPs by S. oneidensis was investigated to generate hybrid biofilms with optimized properties. The biogenic particles exhibited both magnetic and electroactive properties, enabling improved electrical coupling to the electrode without inducing cytotoxic effects. This study proposes a method for expanding the electrode surface in existing BES. This method is controllable, scalable, and easily applicable. It involves applying a magnetic field and adding conductive magnetic NPs. These findings are likely transferable to other electroactive microorganisms as well.
Subjects
Biofilms
Microfluidics
Bioelectrochemical Systems
Exoelectrogens
Electroactive Microorganisms
Magnetic Nanoparticles
Microbial Electrolysis
DDC Class
660: Chemistry; Chemical Engineering
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ReneWurst_Dissertation.pdf
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