1. Articles from Michael Wagner

    1-15 of 15
    1. An open-source robotic platform that enables automated monitoring of replicate biofilm cultivations using optical coherence tomography

      An open-source robotic platform that enables automated monitoring of replicate biofilm cultivations using optical coherence tomography

      The paper introduces a fully automated cultivation and monitoring tool to study biofilm development in replicate experiments operated in parallel. To gain a fundamental understanding of the relation between cultivation conditions and biofilm characteristics (e.g., structural, mechanical) a monitoring setup allowing for the standardization of methods is required. Optical coherence tomography (OCT) is an imaging modality ideal for biofilms since it allows for the monitoring of structure in real time. By integrating an OCT device into the open-source robotic platform EvoBot, a fully automated monitoring platform for investigating biofilm development in several flow cells at once was realized. Different ...

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    2. Monitoring and quantification of bioelectrochemical Kyrpidia spormannii biofilm development in a novel flow cell setup

      Monitoring and quantification of bioelectrochemical Kyrpidia spormannii biofilm development in a novel flow cell setup

      Spatially resolved data for biofilm structure can often not be assessed easily in bioelectrochemical setups due to the orientation and placement of anode and cathode. However, understanding the interplay of biofilm (structure) development and electrochemical parameters is crucial for optimizing bioelectrochemical biofilm systems. For example, to produce value added products. This study thus, presents a versatile flow cell setup allowing for control of hydrodynamic, substrate (liquid and gaseous), and nutritional conditions as well as physical parameters. Here, a versatile lab-scale flow cell system equipped with a cathode and an anode is presented to monitor the growth of Kyrpidia spormannii biofilm ...

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    3. Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large Spatial Scales

      Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large Spatial Scales

      Microbial biofilms form complex architectures at interphases and develop into highly scale-dependent spatial patterns. Here, we introduce an experimental system (hard- and software) for the automated acquisition of 3D optical coherence tomography (OCT) datasets. This toolset allows the non-invasive and multi-scale characterization of biofilm morphogenesis in space and time.

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    4. In-situ monitoring and quantification of fouling development in membrane distillation by means of optical coherence tomography

      In-situ monitoring and quantification of fouling development in membrane distillation by means of optical coherence tomography

      Fouling formation in membrane distillation limits process stability and could cause besides wetting a rapid flux decrease making the process inefficient. Process performance is conventionally assessed by flux monitoring. Optical Coherence Tomography (OCT) enables in-situ visualization and quantification of fouling layers dominated by scaling in a fully operated direct contact membrane distillation system (DCMD). This study presents an innovative methodology for 3D dataset analysis allowing for the detection and quantification of predominant scaling on the membrane surface. Defined fouling parameters permit a correlation between process performance indicators, especially flux decrease and quantified fouling layer coverage. Additionally, structural information about the ...

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    5. Determination of mechanical properties of biofilms by modeling the deformation measured using optical coherence tomography

      Determination of mechanical properties of biofilms by modeling the deformation measured using optical coherence tomography

      The advantage of using non-invasive imaging such as optical coherence tomography (OCT) to asses material properties from deformed biofilm geometries can be compromised by the assumptions made on fluid forces acting on the biofilm. This study developed a method for the determination of elastic properties of biofilms by modelling the biofilm deformation recorded by OCT imaging with poroelastic fluid-structure interaction computations. Two-dimensional biofilm geometries were extracted from OCT scans of non-deformed and deformed structures as a result of hydrodynamic loading. The biofilm geometries were implemented in a model coupling fluid dynamics with elastic solid mechanics and Darcy flow in the ...

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    6. Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      A large fraction of the chemical oxygen demand (COD) in municipal wastewater is associated with the particulate matter. The presence of these particles might impose a negative impact on the mass transfer in biofilm systems when they attach to the bulk-biofilm interface. We thus investigated the impact of real wastewater particles by combining optical coherence tomography (OCT) and oxygen microsensor measurements. The deposition of wastewater particles of different size classes onto the biofilm surface was captured in 3D by means of OCT in a lab-scale flume. The thickness of the particle layer was calculated from OCT images. The influence of ...

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    7. Optical coherence tomography in biofilm research: A comprehensive review

      Optical coherence tomography in biofilm research: A comprehensive review

      Imaging of biofilm systems is a prerequisite for a better understanding of both structure and its function. The review aims to critically discuss the use of optical coherence tomography (OCT) for the visualization of the biofilm structure as well as its dynamic behavior. A short overview on common and well-known, established imaging techniques for biofilms such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), Raman microscopy (RM), and magnetic resonance imaging (MRI) paves the way to imaging biofilms at the mesoscale, which is perfectly covered by means of OCT. Principle, resolution, imaging velocity, and limitations of OCT are ...

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    8. Optical coherence tomography in biofilm research: A comprehensive review

      Optical coherence tomography in biofilm research: A comprehensive review

      Imaging of biofilm systems is a prerequisite for a better understanding of both structure and its function. The review aims to critically discuss the use of optical coherence tomography (OCT) for the visualization of the biofilm structure as well as its dynamic behavior. A short overview on common and well-known, established imaging techniques for biofilms such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), Raman microscopy (RM), and magnetic resonance imaging (MRI) paves the way to imaging biofilms at the mesoscale, which is perfectly covered by means of OCT. Principle, resolution, imaging velocity and limitations of OCT are ...

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    9. Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography

      Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    10. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the ...

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    11. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    12. Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling

      Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling

      Imaging and modeling are two major approaches in biofilm research to understand the physical and biochemical processes involved in biofilm development. However, they are often used separately. In this study we combined these two approaches to investigate substrate mass transfer and mass flux. Cross-sectional biofilm images were acquired by means of optical coherence tomography (OCT) for biofilms grown on carriers. A 2D biofilm model was developed incorporating OCT images as well as a simplified biofilm geometry serving as structural templates. The model incorporated fluid flow, substrate transfer and biochemical conversion of substrates and simulated the hydrodynamics surrounding the biofilm structure ...

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    13. Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography

      Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography

      This study focused on characterizing the structure of biofilms developed on carriers used in lab-scale moving bed biofilm reactors. Both light microscopy (2D) and optical coherence tomography (OCT) were employed to track the biofilm development on carriers of different geometry and under different aeration rates. Biofilm structure was further characterized with respect to average biofilm thickness, biofilm growth velocity, biomass volume, compartment filling degree, surface area, etc. The results showed that carriers with a smaller compartment size stimulated a quick establishment of biofilms. Low aeration rates favored fast development of biofilms. Comparison between the results derived from 2D and 3D ...

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    14. Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      To understand the (bio)fouling development in membrane modules in more detail, three-dimensional in situ imaging of the feed spacer channel by means of optical coherence tomography (OCT) was applied. The biofilm formation was investigated in membrane fouling simulators (MFS) mimicking the feed spacer channel of spiral wound reverse osmosis membrane modules. To test the capability of OCT for the visualization of feed spacer fouling, river water and effluent of a waste water treatment plant were used as feeds. Additionally, the (bio)fouling characteristics of a wide-meshed and small-meshed feed spacer were tested. 3D OCT datasets were quantified and the ...

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    15. Time-resolved Biofilm Deformation Measurements using Optical Coherence Tomography

      Time-resolved Biofilm Deformation Measurements using Optical Coherence Tomography

      The interaction of shear stress with the biofilm leads to a dynamic deformation, which is related to the structural and material characteristics of biofilms. We show how optical coherence tomography can be used as an imaging technique to investigate the time-resolved deformation on the biofilm mesoscale as well as to estimate mechanical properties of the biofilm. For the first time time-resolved deformation from cross-sectional views of the inner biofilm structure could be shown. Changes in the biofilm structure and rheological properties were calculated from cross sections in real time and time-lapsed measurements. Heterotrophic biofilms were grown in a flow cell ...

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    1-15 of 15
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  2. Topics in the News

    1. (9 articles) Karlsruhe Institute of Technology
    2. (3 articles) University of Copenhagen
    3. (3 articles) Oregon Health & Science University
    4. (3 articles) Steven L. Jacques
    5. (2 articles) Delft University of Technology
    6. (2 articles) Daniel Wangpraseurt
    7. (2 articles) Michael Kühl
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    Time-resolved Biofilm Deformation Measurements using Optical Coherence Tomography Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling In vivo imaging of coral tissue and skeleton with optical coherence tomography In vivo imaging of coral tissue and skeleton with optical coherence tomography Feature Of The Week 03/05/2017: In Vivo Imaging of Coral Tissue and Skeleton with Optical Coherence Tomography Optical coherence tomography in biofilm research: A comprehensive review Optical coherence tomography in biofilm research: A comprehensive review Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer The Effect of Anti-Tubercular Drugs on Retinal Nerve Fiber Layer Thickness Using Optical Coherence Tomography A Cross-sectional Optical Coherence Tomography Study in Patients on Taxane-based Therapy and A Case Report with the Literature Review