Journal: Biofilm

Article Title: Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms

doi: 10.1016/j.bioflm.2024.100226

Figure Lengend Snippet: Platform for electroactive biofilm cultivation and analysis. The microfluidic cultivation chips ( a ) are composed of polydimethylsiloxane (PDMS) and the channel is sealed by plasma bonding to a glass slide. A 1 × 1 cm graphite electrode and a 1 × 1 cm neodymium N52 block magnet were integrated in the center, additional access points allow fluidic access via insertion of cannulas, as well as the addition of the tailored reference electrode. Three sets of two microfluidic reactors (anode and cathode), are placed in a chamber ( b ), made up of a bottom plate, frame and lid. The lid is positioned on the anodic compartment to allow for anoxic cultivation by purging with 80 % N 2 /20 % CO 2 gas. A photograph of the frame can be seen in c . This setup and figure are based on the platform presented by Klein et al. and slightly modified for the assembly of magnetic micropillars.

Article Snippet: Graphite composite electrodes (PPG 86, Eisenhuth GmbH & Co. KG, Osterode am Harz, Germany) with an effective surface area of 3 × 10 mm were integrated into the cultivation channel.

Techniques: Blocking Assay, Modification

Journal: Biofilm

Article Title: Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms

doi: 10.1016/j.bioflm.2024.100226

Figure Lengend Snippet: Height map (a) and schematic illustration of conductive, magnetic micropillars (b) on the anode surface and their corresponding nanoparticle building blocks (c). The height map ( a ) provides a top view of the anode surface, decorated with micropillars throughout. The image was generated via OCT measurement and subsequent data processing with Fiji (Is Just ImageJ). A schematic illustration ( b ) shows a zoomed in side view of several micropillars on the anode surface, along with their calculated mean diameter and height. This illustration is simplified for clarification reasons and shows a higher regularity than the height map. In c the single NP building block of the assembled micropillars is illustrated. It consists of a magnetic iron core and a hydrophobic carbon shell.

Article Snippet: Graphite composite electrodes (PPG 86, Eisenhuth GmbH & Co. KG, Osterode am Harz, Germany) with an effective surface area of 3 × 10 mm were integrated into the cultivation channel.

Techniques: Generated, Clarification Assay, Blocking Assay

Journal: Biofilm

Article Title: Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms

doi: 10.1016/j.bioflm.2024.100226

Figure Lengend Snippet: Electrochemical assessment of surface enhancement. Cyclic voltammetry of untreated anode surface (black) and microstructured anode surface (red, a ). By retrieving the values for peak current I p it is possible to calculate the electroactive surface area via Randles-Sevcik equation ( b ). The error bars represent the standard deviation in I p from three cyclic voltammetry cycles. Asterisks represent significant differences (unpaired t -test: ∗∗ = p < 0.01). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Article Snippet: Graphite composite electrodes (PPG 86, Eisenhuth GmbH & Co. KG, Osterode am Harz, Germany) with an effective surface area of 3 × 10 mm were integrated into the cultivation channel.

Techniques: Standard Deviation

Journal: Biofilm

Article Title: Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms

doi: 10.1016/j.bioflm.2024.100226

Figure Lengend Snippet: Comparison of current density with and without the use of conductive, magnetic micropillars for S. oneidensis and G. sulfurreducens . In panels a , c , and e , the current densities for S. oneidensis are shown for three conditions: without NP addition (Control I), with NP addition but without a magnet placed beneath the anode (Control II), and with NP addition and a magnet positioned below the anode (Micropillars). In panels b, d, and f, the current densities for G. sulfurreducens are presented for two conditions: without NP addition (Control) and with NP addition along with a magnet placed below the anode (Micropillars). a and b show the current density over time of S. oneidensis and G. sulfurreducens , respectively. In a the inoculation time (first 2 h) is indicated with a grey box. In c and d the mean current densities after 40 h of both microorganisms are plotted, while e and f show the steady state current densities. Error bars represent the standard deviation from individual triplicates and in case of Control II from individual duplicates. Asterisks represent significant differences towards Control I and Control, respectively (unpaired t -test: ∗∗ = p < 0.01).

Article Snippet: Graphite composite electrodes (PPG 86, Eisenhuth GmbH & Co. KG, Osterode am Harz, Germany) with an effective surface area of 3 × 10 mm were integrated into the cultivation channel.

Techniques: Comparison, Control, Standard Deviation