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Clark GG, Geisler D, Coey EJ, Pollitz LJ, Zaki FR, Huang C, Boppart SA, Nguyen TH. Influence of phosphate on bacterial release from activated carbon point-of-use filters and on biofilm characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169932. [PMID: 38199359 PMCID: PMC11090127 DOI: 10.1016/j.scitotenv.2024.169932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/29/2023] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Abstract
Point-of-use (POU) filters certified to remove lead are often composed of activated carbon and have been shown to release high concentrations of bacteria, including opportunistic pathogens. In this study, we examine the impacts of the common corrosion inhibitor phosphate on biofilm characteristics and the relationship between biofilm structure and bacterial release from POU filters. This knowledge is essential for understanding how best to use the filters and where these filters fit in a system where other lead contamination prevention measures may be in place. We measured the bacterial release from activated carbon POU filters fed with groundwater - a common source of drinking water - with and without phosphate. We used optical coherence tomography (OCT) to quantitatively characterize biofilm growing on activated carbon filter material in which the biofilms were fed groundwater with and without phosphate. Phosphate filters released significantly less (57-87 %) bacteria than groundwater filters, and phosphate biofilms (median thickness: 82-331 μm) grew to be significantly thicker than groundwater biofilms (median thickness: 122-221 μm). The phosphate biofilm roughness ranged from 97 to 142 % of the groundwater biofilm roughness and was significantly greater in most weeks. Phosphate biofilms also had fewer pores per biofilm volume and shorter channels connecting those pores.
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Affiliation(s)
- Gemma G Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America.
| | - Dietrich Geisler
- Department of Computer Science, Cornell University, United States of America
| | - Evan J Coey
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Lance J Pollitz
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Farzana R Zaki
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States of America
| | - Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Stephen A Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States of America; Department of Bioengineering, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, United States of America; Carle Illinois College of Medicine, United States of America
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America; Carle Illinois College of Medicine, United States of America; Institute of Genomic Biology, University of Illinois at Urbana-Champaign, United States of America
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2
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Deng YH, Ricciardulli T, Won J, Wade MA, Rogers SA, Boppart SA, Flaherty DW, Kong H. Self-locomotive, antimicrobial microrobot (SLAM) swarm for enhanced biofilm elimination. Biomaterials 2022; 287:121610. [PMID: 35696784 PMCID: PMC9763052 DOI: 10.1016/j.biomaterials.2022.121610] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 05/29/2022] [Indexed: 12/20/2022]
Abstract
Biofilm is a major cause of infections and infrastructure deterioration, largely due to molecular diffusion restrictions that hamper the antimicrobial activity of traditional antibiotics and disinfectants. Here, we present a self-locomotive, antimicrobial microrobot (SLAM) swarm that can penetrate, fracture, and detach biofilm and, in turn, nullify bacterial resistance to antibiotics. The SLAM is assembled by loading a controlled mass of manganese oxide nanosheets on diatoms with the polydopamine binder. In hydrogen peroxide solution, SLAMs produce oxygen bubbles that generate thrust to penetrate the rigid and dense Pseudomonas aeruginosa biofilm and self-assemble into a swarm that repeatedly surrounds, expands, and bursts oxygen bubbles. The resulting cavities continue to deform and fracture extracellular polymeric substances from microgrooved silicone substrates and wounded skin explants while decreasing the number of viable bacterial cells. Additionally, SLAM allows irrigating water or antibiotics to access the residual biofilm better, thus enhancing the synergistic efficacy in killing up to 99.9% of bacterial cells.
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Affiliation(s)
- Yu-Heng Deng
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Tomas Ricciardulli
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Jungeun Won
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Matthew A Wade
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Simon A Rogers
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Stephen A Boppart
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - David W Flaherty
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA
| | - Hyunjoon Kong
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana- Champaign, Urbana, IL, 61801, USA; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seongbuk-gu, Seoul, 02841, South Korea.
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3
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Pereira J, de Nooy S, Sleutels T, Ter Heijne A. Opportunities for visual techniques to determine characteristics and limitations of electro-active biofilms. Biotechnol Adv 2022; 60:108011. [PMID: 35753624 DOI: 10.1016/j.biotechadv.2022.108011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/10/2022] [Accepted: 06/18/2022] [Indexed: 11/02/2022]
Abstract
Optimization of bio-electrochemical systems (BESs) relies on a better understanding of electro-active biofilms (EABfs). These microbial communities are studied with a range of techniques, including electrochemical, visual and chemical techniques. Even though each of these techniques provides very valuable and wide-ranging information about EABfs, such as performance, morphology and biofilm composition, they are often destructive. Therefore, the information obtained from EABfs development and characterization studies are limited to a single characterization of EABfs and often limited to one time point that determines the end of the experiment. Despite being scarcer and not as commonly reported as destructive techniques, non-destructive visual techniques can be used to supplement EABfs characterization by adding in-situ information of EABfs functioning and its development throughout time. This opens the door to EABfs monitoring studies that can complement the information obtained with destructive techniques. In this review, we provide an overview of visual techniques and discuss the opportunities for combination with the established electrochemical techniques to study EABfs. By providing an overview of suitable visual techniques and discussing practical examples of combination of visual with electrochemical methods, this review aims at serving as a source of inspiration for future studies in the field of BESs.
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Affiliation(s)
- João Pereira
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Sam de Nooy
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands
| | - Tom Sleutels
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911, MA, Leeuwarden, the Netherlands; Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708, WG, Wageningen, the Netherlands.
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4
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Sutariya B, Sargaonkar A, Raval H. Methods of visualizing hydrodynamics and fouling in membrane filtration systems: recent trends. SEP SCI TECHNOL 2022. [DOI: 10.1080/01496395.2022.2089585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Bhaumik Sutariya
- Membrane Science and Separation Technology Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Aabha Sargaonkar
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
- Cleaner Technology and Modelling Division, CSIR-National Environmental Engineering Research Institute, Nagpur, India
| | - Hiren Raval
- Membrane Science and Separation Technology Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Bhavnagar, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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5
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Pattem J, Davrandi M, Aguayo S, Slak B, Maev R, Allan E, Spratt D, Bozec L. Dependency of hydration and growth conditions on the mechanical properties of oral biofilms. Sci Rep 2021; 11:16234. [PMID: 34376751 PMCID: PMC8355335 DOI: 10.1038/s41598-021-95701-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022] Open
Abstract
Within the oral cavity, dental biofilms experience dynamic environments, in part due to changes in dietary content, frequency of intake and health conditions. This can impact bacterial diversity and morpho-mechanical properties. While phenotypic properties of oral biofilms are closely related to their composition, these can readily change according to dynamic variations in the growth environment and nutrient availability. Understanding the interlink between phenotypic properties, variable growth conditions, and community characterization is an essential requirement to develop structure–property relationships in oral-biofilms. In this study, the impact of two distinct growth media types with increasing richness on the properties of oral biofilms was assessed through a new combination of in-vitro time-lapse biophysical methods with microbiological assays. Oral biofilms grown in the enriched media composition presented a decrease in their pH, an increase in soluble EPS production, and a severe reduction in bacterial diversity. Additionally, enriched media conditions presented an increase in biofilm volumetric changes (upon hydration) as well as a reduction in elastic modulus upon indentation. With hydration time considered a major factor contributing to changes in biofilm mechanical properties, we have shown that it is less associated than media richness. Future investigations can now use this time-lapse approach, with a clearer focus on the extracellular matrix of oral biofilms dictating their morpho-mechanical properties.
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Affiliation(s)
- J Pattem
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK. .,National Centre for Molecular Hydrodynamics, and Soft Matter Biomaterials and Bio-Interfaces, University of Nottingham, The Limes Building, Sutton Bonington Campus, Sutton Bonington, Leicestershire, LE12 5RD, UK.
| | - M Davrandi
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - S Aguayo
- School of Dentistry, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - B Slak
- Department of Electrical and Computer Engineering, University of Windsor, Windsor, Canada
| | - R Maev
- Department of Electrical and Computer Engineering, University of Windsor, Windsor, Canada
| | - E Allan
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - D Spratt
- Division of Microbial Diseases, UCL Eastman Dental Institute, University College London, London, UK
| | - L Bozec
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK.,Faculty of Dentistry, University of Toronto, Toronto, Canada
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6
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Yuan L, de Haan P, Peterson BW, de Jong ED, Verpoorte E, van der Mei HC, Busscher HJ. Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:1211-1219. [PMID: 33107427 DOI: 10.1017/s143192762002454x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Imaging of cellular layers in a gut-on-a-chip system has been confined to two-dimensional (2D)-imaging through conventional light microscopy and confocal laser scanning microscopy (CLSM) yielding three-dimensional- and 2D-cross-sectional reconstructions. However, CLSM requires staining and is unsuitable for longitudinal visualization. Here, we compare merits of optical coherence tomography (OCT) with those of CLSM and light microscopy for visualization of intestinal epithelial layers during protection by a probiotic Bifidobacterium breve strain and a simultaneous pathogen challenge by an Escherichia coli strain. OCT cross-sectional images yielded film thicknesses that coincided with end-point thicknesses derived from cross-sectional CLSM images. Light microscopy on histological sections of epithelial layers at the end-point yielded smaller layer thicknesses than OCT and CLSM. Protective effects of B. breve adhering to an epithelial layer against an E. coli challenge included the preservation of layer thickness and membrane surface coverage by epithelial cells. OCT does not require staining or sectioning, making OCT suitable for longitudinal visualization of biological films, but as a drawback, OCT does not allow an epithelial layer to be distinguished from bacterial biofilms adhering to it. Thus, OCT is ideal to longitudinally evaluate epithelial layers under probiotic protection and pathogen challenges, but proper image interpretation requires the application of a second method at the end-point to distinguish bacterial and epithelial films.
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Affiliation(s)
- Lu Yuan
- Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, 9713 AVGroningen, The Netherlands
| | - Pim de Haan
- University of Groningen, Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, 9713 AVGroningen, The Netherlands
- TI-COAST, 1098 XHAmsterdam, The Netherlands
| | - Brandon W Peterson
- Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, 9713 AVGroningen, The Netherlands
| | - Ed D de Jong
- Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, 9713 AVGroningen, The Netherlands
| | - Elisabeth Verpoorte
- University of Groningen, Groningen Research Institute of Pharmacy, Pharmaceutical Analysis, 9713 AVGroningen, The Netherlands
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, 9713 AVGroningen, The Netherlands
| | - Henk J Busscher
- Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, 9713 AVGroningen, The Netherlands
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7
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Huang C, Sun PP, Won J, Wang Y, Boppart SA, Nguyen TH. Effect of Nonphosphorus Corrosion Inhibitors on Biofilm Pore Structure and Mechanical Properties. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14716-14724. [PMID: 33124800 PMCID: PMC7949192 DOI: 10.1021/acs.est.0c04645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Understanding the effects of biofilm structural and mechanical properties, which can influence biofilm cohesiveness and detachment under physical stress, is critical for biofilm and biofilm-associated pathogen control. In this study, we used optical coherence tomography (OCT) and nanoindentation to determine the role of silicate and tin (two experimental nonphosphate corrosion inhibitors) on the porous structure and stiffness of three types of multispecies biofilms. These biofilms were grown from groundwater (a drinking water source), and this groundwater was amended with either tin or silicate corrosion inhibitor (0.5 mg/L as Sn and 20 mg/L as SiO2). Based on the elastic moduli of these biofilms, tin biofilms and groundwater biofilms were the stiffest, followed by silicate biofilms. The thickness normalized by the growth time for silicate biofilms was highest at 38 ± 7.1 μm/month, compared to 21 ± 3.2 and 11 ± 2.4 μm/month for tin biofilms and groundwater biofilms, respectively. The silicate biofilms had the greatest overall porosities and were thickest among the three biofilms. Based on the pore network modeling (PNM) of OCT images, larger pores and connections were found in the silicate biofilms compared to those in tin and groundwater biofilms. Our analysis showed that the thicker and more porous biofilms (silicate biofilms) were potentially less resistant to deformation than the thinner and denser biofilms (tin and groundwater biofilms).
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peter P Sun
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jungeun Won
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Yin Wang
- Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, United States
| | - Stephen A Boppart
- Departments of Electrical and Computer Engineering and Bioengineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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8
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Tummons E, Han Q, Tanudjaja HJ, Hejase CA, Chew JW, Tarabara VV. Membrane fouling by emulsified oil: A review. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.116919] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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9
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Rooney LM, Amos WB, Hoskisson PA, McConnell G. Intra-colony channels in E. coli function as a nutrient uptake system. THE ISME JOURNAL 2020; 14:2461-2473. [PMID: 32555430 PMCID: PMC7490401 DOI: 10.1038/s41396-020-0700-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
The ability of microorganisms to grow as aggregated assemblages has been known for many years, however their structure has remained largely unexplored across multiple spatial scales. The development of the Mesolens, an optical system which uniquely allows simultaneous imaging of individual bacteria over a 36 mm2 field of view, has enabled the study of mature Escherichia coli macro-colony biofilm architecture like never before. The Mesolens enabled the discovery of intra-colony channels on the order of 10 μm in diameter, that are integral to E. coli macro-colony biofilms and form as an emergent property of biofilm growth. These channels have a characteristic structure and re-form after total mechanical disaggregation of the colony. We demonstrate that the channels are able to transport particles and play a role in the acquisition of and distribution of nutrients through the biofilm. These channels potentially offer a new route for the delivery of dispersal agents for antimicrobial drugs to biofilms, ultimately lowering their impact on public health and industry.
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Affiliation(s)
- Liam M Rooney
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK.
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - William B Amos
- Department of Physics, SUPA, University of Strathclyde, 107 Rottenrow East, Glasgow, G4 0NG, UK
| | - Paul A Hoskisson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Gail McConnell
- Department of Physics, SUPA, University of Strathclyde, 107 Rottenrow East, Glasgow, G4 0NG, UK
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10
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Koch C, Kuchenbuch A, Marosvölgyi M, Weisshart K, Harnisch F. Label‐Free Four‐Dimensional Visualization of Anaerobically Growing Electroactive Biofilms. Cytometry A 2020; 97:737-741. [DOI: 10.1002/cyto.a.24169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 01/27/2023]
Affiliation(s)
- Christin Koch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
| | - Anne Kuchenbuch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
| | | | - Klaus Weisshart
- Carl Zeiss Microscopy GmbH Carl‐Zeiss‐Promenade 10, Jena 07745 Germany
| | - Falk Harnisch
- Department of Environmental MicrobiologyHelmholtz Center for Environmental Research GmbH – UFZ Permoserstraße 15, Leipzig 04318 Germany
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11
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Caizán-Juanarena L, Krug JR, Vergeldt FJ, Kleijn JM, Velders AH, Van As H, Ter Heijne A. 3D biofilm visualization and quantification on granular bioanodes with magnetic resonance imaging. WATER RESEARCH 2019; 167:115059. [PMID: 31562986 DOI: 10.1016/j.watres.2019.115059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
The use of microbial fuel cells (MFCs) for wastewater treatment fits in a circular economy context, as they can produce electricity by the removal of organic matter in the wastewater. Activated carbon (AC) granules are an attractive electrode material for bioanodes in MFCs, as they are cheap and provide electroactive bacteria with a large surface area for attachment. The characterization of biofilm growth on AC granules, however, is challenging due to their high roughness and three-dimensional structure. In this research, we show that 3D magnetic resonance imaging (MRI) can be used to visualize biofilm distribution and determine its volume on irregular-shaped single AC granules in a non-destructive way, while being combined with electrochemical and biomass analyses. Ten AC granules with electroactive biofilm (i.e. granular bioanodes) were collected at different growth stages (3 to 21 days after microbial inoculation) from a multi-anode MFC and T1-weighted 3D-MRI experiments were performed for three-dimensional biofilm visualization. With time, a more homogeneous biofilm distribution and an increased biofilm thickness could be observed in the 3D-MRI images. Biofilm volumes varied from 0.4 μL (day 4) to 2 μL (day 21) and were linearly correlated (R2 = 0.9) to the total produced electric charge and total nitrogen content of the granular bioanodes, with values of 66.4 C μL-1 and 17 μg N μL-1, respectively. In future, in situ MRI measurements could be used to monitor biofilm growth and distribution on AC granules.
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Affiliation(s)
- Leire Caizán-Juanarena
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Julia R Krug
- Laboratory of BioNanoTechnology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands; Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Frank J Vergeldt
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - J Mieke Kleijn
- Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Aldrik H Velders
- Laboratory of BioNanoTechnology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Henk Van As
- Laboratory of Biophysics, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands; MAGNEtic resonance research FacilitY, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands.
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12
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Kerdi S, Qamar A, Alpatova A, Ghaffour N. An in-situ technique for the direct structural characterization of biofouling in membrane filtration. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2019.04.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Bauer A, Wagner M, Saravia F, Bartl S, Hilgenfeldt V, Horn H. In-situ monitoring and quantification of fouling development in membrane distillation by means of optical coherence tomography. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2019.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Yang J, Cheng S, Li P, Huang H, Cen K. Sensitivity to Oxygen in Microbial Electrochemical Systems Biofilms. iScience 2019; 13:163-172. [PMID: 30844696 PMCID: PMC6402288 DOI: 10.1016/j.isci.2019.01.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/23/2018] [Accepted: 01/15/2019] [Indexed: 11/21/2022] Open
Abstract
The formation and bioelectric performance of anode biofilms in microbial electrochemical systems (MESs) are sensitive to oxygen. Investigating the temporal-spatial structure of anode biofilms will help elucidate the interfaces between oxygen and bacteria, thereby facilitating the applications of MESs in wastewater treatment and energy recovery. Here, use of optical coherence tomography, frozen sections, and a microsensor revealed that the aerobic biofilms exhibited a multilayered sandwich structure with a sparse gap between the aerobe- and amphimicrobe-enriched outer layer and the dense exoelectrogen-enriched inner layer, whereas the anaerobic biofilm consisted of only a single dense layer. Our results showed that the inner layer of aerobic anode biofilms performed electricity generation, whereas the outer layer only consumed oxygen. In this case, electron donor diffusion through the outer layer became the limiting factor in electricity generation by the bioanode. Consequently, as the anode biofilms matured, current generation decreased.
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Affiliation(s)
- Jiawei Yang
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, PR China
| | - Shaoan Cheng
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, PR China.
| | - Peng Li
- State Key Lab of Modern Optical Instrumentation and the Collaborative Innovation Center for Brain Science, College of Optical Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, PR China
| | - Haobin Huang
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, PR China
| | - Kefa Cen
- State Key Laboratory of Clean Energy, Department of Energy Engineering, Zhejiang University, Hangzhou 310027, PR China
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15
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Picioreanu C, Blauert F, Horn H, Wagner M. Determination of mechanical properties of biofilms by modelling the deformation measured using optical coherence tomography. WATER RESEARCH 2018; 145:588-598. [PMID: 30199803 DOI: 10.1016/j.watres.2018.08.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/25/2018] [Accepted: 08/30/2018] [Indexed: 05/28/2023]
Abstract
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 biofilm. The simulation results were compared with real deformed geometries and a fitting procedure allowed estimation of the Young's modulus in given flow conditions. The present method considerably improves the estimation of elastic moduli of biofilms grown in mini-fluidic rectangular channels. This superior prediction is based on the relaxation of several simplifying assumptions made in past studies: shear stress is not anymore taken constant over the biofilm surface, total stress including also pressure is accounted for, any biofilm shape can be used in the determinations, and non-linear behavior of mechanical properties can be estimated. Biofilm elastic moduli between 70 and 700 Pa were obtained and biofilm hardening at large applied stress due to increasing flow velocity was quantified. The work performed here opens the way for in-situ determination of other mechanical properties (e.g., viscoelastic properties, relaxation times, plastic yields) and provides data for modelling biofilm deformation and detachment with eventual applications in biofilm control and removal strategies.
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Affiliation(s)
- Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands.
| | - Florian Blauert
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Harald Horn
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Wagner
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
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16
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Sun PP, Araud EM, Huang C, Shen Y, Monroy GL, Zhong S, Tong Z, Boppart SA, Eden JG, Nguyen TH. Disintegration of simulated drinking water biofilms with arrays of microchannel plasma jets. NPJ Biofilms Microbiomes 2018; 4:24. [PMID: 30374407 PMCID: PMC6194111 DOI: 10.1038/s41522-018-0063-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 12/21/2022] Open
Abstract
Biofilms exist and thrive within drinking water distribution networks, and can present human health concerns. Exposure of simulated drinking water biofilms, grown from groundwater, to a 9 × 9 array of microchannel plasma jets has the effect of severely eroding the biofilm and deactivating the organisms they harbor. In-situ measurements of biofilm structure and thickness with an optical coherence tomography (OCT) system show the biofilm thickness to fall from 122 ± 17 µm to 55 ± 13 µm after 15 min. of exposure of the biofilm to the microplasma column array, when the plasmas are dissipating a power density of 58 W/cm2. All biofilms investigated vanish with 20 min. of exposure. Confocal laser scanning microscopy (CLSM) demonstrates that the number of living cells in the biofilms declines by more than 93% with 15 min. of biofilm exposure to the plasma arrays. Concentrations of several oxygen-bearing species, generated by the plasma array, were found to be 0.4–21 nM/s for the hydroxyl radical (OH), 85–396 nM/s for the 1O2 excited molecule, 98–280 µM for H2O2, and 24–42 µM for O3 when the power density delivered to the array was varied between 3.6 W/cm2 and 79 W/cm2. The data presented here demonstrate the potential of microplasma arrays as a tool for controlling, through non-thermal disruption and removal, mixed-species biofilms prevalent in commercial and residential water systems. Biofilms in drinking water premise plumbing systems can be disrupted and their microorganisms deactivated by exposure to jets of ionized gas known as plasma. Researchers at the University of Illinois, USA, led by Thanh (Helen) Nguyen and J. Gary Eden, explored the potential of low temperature plasma jets in disrupting & removing drinking water biofilms. The plasma was directed through fabricated microchannels and onto samples that the simulated biofilms. The interaction of the plasma with air and water generated reactive chemical species and ultraviolet radiation that disrupted the biofilms and deactivated the microorganisms within them. The biofilms studied vanished within 20 min. of plasma exposure. Plasma jets offer an inexpensive, low temperature and chlorine-free method for combating harmful biofilms in drinking water premise plumbing systems.
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Affiliation(s)
- Peter P Sun
- 1Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 USA.,2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Elbashir M Araud
- 1Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Conghui Huang
- 1Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Yun Shen
- 1Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 USA.,4Present Address: Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Guillermo L Monroy
- 3Department of Bioengineering, University of Illinois, Urbana, IL 61801 USA
| | - Shengyun Zhong
- 2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Zikang Tong
- 2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Stephen A Boppart
- 2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801 USA.,3Department of Bioengineering, University of Illinois, Urbana, IL 61801 USA
| | - J Gary Eden
- 2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL 61801 USA
| | - Thanh H Nguyen
- 1Department of Civil and Environmental Engineering, University of Illinois, Urbana, IL 61801 USA
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17
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Shen Y, Huang PC, Huang C, Sun P, Monroy GL, Wu W, Lin J, Espinosa-Marzal RM, Boppart SA, Liu WT, Nguyen TH. Effect of divalent ions and a polyphosphate on composition, structure, and stiffness of simulated drinking water biofilms. NPJ Biofilms Microbiomes 2018; 4:15. [PMID: 30038792 PMCID: PMC6052100 DOI: 10.1038/s41522-018-0058-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 05/24/2018] [Accepted: 06/01/2018] [Indexed: 02/04/2023] Open
Abstract
The biofilm chemical and physical properties in engineered systems play an important role in governing pathogen transmission, fouling facilities, and corroding metal surfaces. Here, we investigated how simulated drinking water biofilm chemical composition, structure, and stiffness responded to the common scale control practice of adjusting divalent ions and adding polyphosphate. Magnetomotive optical coherence elastography (MM-OCE), a tool developed for diagnosing diseased tissues, was used to determine biofilm stiffness in this study. MM-OCE, together with atomic force microscopy (AFM), revealed that the biofilms developed from a drinking water source with high divalent ions were stiffer compared to biofilms developed either from the drinking water source with low divalent ions or the water containing a scale inhibitor (a polyphosphate). The higher stiffness of biofilms developed from the water containing high divalent ions was attributed to the high content of calcium carbonate, suggested by biofilm composition examination. In addition, by examining the biofilm structure using optical coherence tomography (OCT), the highest biofilm thickness was found for biofilms developed from the water containing the polyphosphate. Compared to the stiff biofilms developed from the water containing high divalent ions, the soft and thick biofilms developed from the water containing polyphosphate will be expected to have higher detachment under drinking water flow. This study suggested that water chemistry could be used to predict the biofilm properties and subsequently design the microbial safety control strategies. A variety of analytical techniques are revealing the complex influences of ions in drinking water supplies on the structure of biofilms. Such biofilms often contaminate water supply pipes and machinery. Yun Shen and colleagues at the University of Illinois at Urbana-Champaign in the USA investigated the effects of ions with a double positive charge – ‘divalent cations’ – and polyphosphate ions. Divalent cations, especially calcium and magnesium ions, are abundant in drinking water in many regions, promoting the formation of limescale deposits. Polyphosphates are commonly added to water supplies to reduce limescale formation, inhibit corrosion and discourage biofilm formation. The research revealed that divalent cations increase biofilm stiffness, while polyphosphates promote softer but thicker biofilms that are more easily removed. The results will help optimize water treatment procedures to control both microbial contamination and limescale problems.
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Affiliation(s)
- Yun Shen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,4Present Address: University of Michigan, 1351 Beal Ave., 219 EWRE Bldg, Ann Arbor, MI 48109-2125 USA
| | - Pin Chieh Huang
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Conghui Huang
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Peng Sun
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Guillermo L Monroy
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wenjing Wu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Jie Lin
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Rosa M Espinosa-Marzal
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Stephen A Boppart
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,3Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wen-Tso Liu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Thanh H Nguyen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
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18
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Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
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Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
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19
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Wang Y, Guan A, Wickramasekara S, Phillips KS. Analytical Chemistry in the Regulatory Science of Medical Devices. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:307-327. [PMID: 29579404 DOI: 10.1146/annurev-anchem-061417-125556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the United States, regulatory science is the science of developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of all Food and Drug Administration-regulated products. Good regulatory science facilitates consumer access to innovative medical devices that are safe and effective throughout the Total Product Life Cycle (TPLC). Because the need to measure things is fundamental to the regulatory science of medical devices, analytical chemistry plays an important role, contributing to medical device technology in two ways: It can be an integral part of an innovative medical device (e.g., diagnostic devices), and it can be used to support medical device development throughout the TPLC. In this review, we focus on analytical chemistry as a tool for the regulatory science of medical devices. We highlight recent progress in companion diagnostics, medical devices on chips for preclinical testing, mass spectrometry for postmarket monitoring, and detection/characterization of bacterial biofilm to prevent infections.
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Affiliation(s)
- Yi Wang
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Office of Medical Products and Tobacco, US Food and Drug Administration, Silver Spring, Maryland 20993, USA;
| | - Allan Guan
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Office of Medical Products and Tobacco, US Food and Drug Administration, Silver Spring, Maryland 20993, USA;
| | - Samanthi Wickramasekara
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Office of Medical Products and Tobacco, US Food and Drug Administration, Silver Spring, Maryland 20993, USA;
| | - K Scott Phillips
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Office of Medical Products and Tobacco, US Food and Drug Administration, Silver Spring, Maryland 20993, USA;
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20
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A Multi-scale Biophysical Approach to Develop Structure-Property Relationships in Oral Biofilms. Sci Rep 2018; 8:5691. [PMID: 29632310 PMCID: PMC5890245 DOI: 10.1038/s41598-018-23798-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/19/2018] [Indexed: 11/09/2022] Open
Abstract
Over the last 5–10 years, optical coherence tomography (OCT) and atomic force microscopy (AFM) have been individually applied to monitor the morphological and mechanical properties of various single-species biofilms respectively. This investigation looked to combine OCT and AFM as a multi-scale approach to understand the role sucrose concentration and age play in the morphological and mechanical properties of oral, microcosm biofilms, in-vitro. Biofilms with low (0.1% w/v) and high (5% w/v) sucrose concentrations were grown on hydroxyapatite (HAP) discs from pooled human saliva and incubated for 3 and 5 days. Distinct mesoscale features of biofilms such as regions of low and high extracellular polymeric substances (EPS) were identified through observations made by OCT. Mechanical analysis revealed increasing sucrose concentration decreased Young’s modulus and increased cantilever adhesion (p < 0.0001), relative to the biofilm. Increasing age was found to decrease adhesion only (p < 0.0001). This was due to mechanical interactions between the indenter and the biofilm increasing as a function of increased EPS content, due to increasing sucrose. An expected decrease in EPS cantilever contact decreased adhesion due to bacteria proliferation with biofilm age. The application OCT and AFM revealed new structure-property relationships in oral biofilms, unattainable if the techniques were used independently.
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21
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Sønderholm M, Koren K, Wangpraseurt D, Jensen PØ, Kolpen M, Kragh KN, Bjarnsholt T, Kühl M. Tools for studying growth patterns and chemical dynamics of aggregated Pseudomonas aeruginosa exposed to different electron acceptors in an alginate bead model. NPJ Biofilms Microbiomes 2018; 4:3. [PMID: 29479470 PMCID: PMC5818519 DOI: 10.1038/s41522-018-0047-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/07/2018] [Accepted: 01/24/2018] [Indexed: 12/31/2022] Open
Abstract
In chronic infections, bacterial pathogens typically grow as small dense cell aggregates embedded in a matrix consisting of, e.g., wound bed sludge or lung mucus. Such biofilm growth mode exhibits extreme tolerance towards antibiotics and the immune defence system. The bacterial aggregates are exposed to physiological heterogeneity and O2 limitation due to steep chemical gradients through the matrix, which is are hypothesised to contribute to antibiotic tolerance. Using a novel combination of microsensor and bioimaging analysis, we investigated growth patterns and chemical dynamics of the pathogen Pseudomonas aeruginosa in an alginate bead model, which mimics growth in chronic infections better than traditional biofilm experiments in flow chambers. Growth patterns were strongly affected by electron acceptor availability and the presence of chemical gradients, where the combined presence of O2 and nitrate yielded highest bacterial growth by combined aerobic respiration and denitrification.
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Affiliation(s)
- Majken Sønderholm
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
| | - Klaus Koren
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
| | - Daniel Wangpraseurt
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Peter Østrup Jensen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Kasper Nørskov Kragh
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Michael Kühl
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
- Climate Change Cluster, University of Technology Sydney, Broadway, NSW 2007 Australia
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22
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Carrel M, Beltran MA, Morales VL, Derlon N, Morgenroth E, Kaufmann R, Holzner M. Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools. PLoS One 2017; 12:e0180374. [PMID: 28732010 PMCID: PMC5521744 DOI: 10.1371/journal.pone.0180374] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 06/14/2017] [Indexed: 11/21/2022] Open
Abstract
X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample. Here, we use a natural inorganic compound, namely iron sulfate, as a contrast agent progressively bounded in dilute or colloidal form into the EPS matrix during biofilm growth. By combining a very long source-to-detector distance on a X-ray laboratory source with a Lorentzian filter implemented prior to tomographic reconstruction, we substantially increase the contrast between the biofilm and the surrounding liquid, which allows revealing the 3D biofilm morphology. A comparison of this new method with the method proposed by Davit et al (Davit et al., 2011), which uses barium sulfate as a contrast agent to mark the liquid phase was performed. Quantitative evaluations between the methods revealed substantial differences for the volumetric fractions obtained from both methods. Namely, contrast agent—biofilm interactions (e.g. biofilm detachment) occurring during barium sulfate injection caused a reduction of the biofilm volumetric fraction of more than 50% and displacement of biofilm patches elsewhere in the column. Two key advantages of the newly proposed method are that passive addition of iron sulfate maintains the integrity of the biofilm prior to imaging, and that the biofilm itself is marked by the contrast agent, rather than the liquid phase as in other available methods. The iron sulfate method presented can be applied to understand biofilm development and bioclogging mechanisms in porous materials and the obtained biofilm morphology could be an ideal basis for 3D numerical calculations of hydrodynamic conditions to investigate biofilm-flow coupling.
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Affiliation(s)
- Maxence Carrel
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
| | - Mario A. Beltran
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf, Switzerland
| | - Verónica L. Morales
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Department of Civil and Environmental Engineering, University of California Davis, Davis, California, United States of America
| | - Nicolas Derlon
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
| | - Rolf Kaufmann
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf, Switzerland
| | - Markus Holzner
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- * E-mail:
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23
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Wagner M, Horn H. Optical coherence tomography in biofilm research: A comprehensive review. Biotechnol Bioeng 2017; 114:1386-1402. [DOI: 10.1002/bit.26283] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/10/2017] [Accepted: 03/01/2017] [Indexed: 01/29/2023]
Affiliation(s)
- Michael Wagner
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
- Karlsruhe Institute of Technology; Institute of Functional Interfaces; Eggenstein-Leopoldshafen Germany
| | - Harald Horn
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
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24
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Miquel Guennoc C, Rose C, Guinnet F, Miquel I, Labbé J, Deveau A. A New Method for Qualitative Multi-scale Analysis of Bacterial Biofilms on Filamentous Fungal Colonies Using Confocal and Electron Microscopy. J Vis Exp 2017. [PMID: 28190036 PMCID: PMC5352296 DOI: 10.3791/54771] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bacterial biofilms frequently form on fungal surfaces and can be involved in numerous bacterial-fungal interaction processes, such as metabolic cooperation, competition, or predation. The study of biofilms is important in many biological fields, including environmental science, food production, and medicine. However, few studies have focused on such bacterial biofilms, partially due to the difficulty of investigating them. Most of the methods for qualitative and quantitative biofilm analyses described in the literature are only suitable for biofilms forming on abiotic surfaces or on homogeneous and thin biotic surfaces, such as a monolayer of epithelial cells. While laser scanning confocal microscopy (LSCM) is often used to analyze in situ and in vivo biofilms, this technology becomes very challenging when applied to bacterial biofilms on fungal hyphae, due to the thickness and the three dimensions of the hyphal networks. To overcome this shortcoming, we developed a protocol combining microscopy with a method to limit the accumulation of hyphal layers in fungal colonies. Using this method, we were able to investigate the development of bacterial biofilms on fungal hyphae at multiple scales using both LSCM and scanning electron microscopy (SEM). This report describes the protocol, including microorganism cultures, bacterial biofilm formation conditions, biofilm staining, and LSCM and SEM visualizations.
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Affiliation(s)
| | - Christophe Rose
- Ecologie et Ecophysiologie Forestières - PTEF, UMR 1137, INRA Université de Lorraine
| | - Frédéric Guinnet
- Interactions Arbres - Microorganismes, UMR1136, INRA Université de Lorraine
| | - Igor Miquel
- Interactions Arbres - Microorganismes, UMR1136, INRA Université de Lorraine
| | - Jessy Labbé
- Biosciences Division, Oak Ridge National Laboratory
| | - Aurélie Deveau
- Interactions Arbres - Microorganismes, UMR1136, INRA Université de Lorraine;
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Antibacterial and anti-biofilm efficacy of fluoropolymer coating by a 2,3,5,6-tetrafluoro-p-phenylenedimethanol structure. Colloids Surf B Biointerfaces 2016; 151:363-371. [PMID: 28056438 DOI: 10.1016/j.colsurfb.2016.12.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/10/2016] [Accepted: 12/14/2016] [Indexed: 11/20/2022]
Abstract
Fluorinated polymers generally function as antibacterial agents, but their anti-biofilm effect remains unresolved. This study investigates the efficacy of fluoropolymers containing 2,3,5,6-tetrafluoro-p-phenylenedimethanol (TFPDM) in preventing biofilm formation by Bacillus subtilis and Escherichia coli (Gram-positive and Gram-negative bacterial species). To this end, TFPDM-based acrylate and epoxy polymers (AF and EF, respectively) and their structural analogues without TFPDM (A and E, respectively) were synthesized. All polymers were coated onto polyethylene terephthalate (PET) sheets. Relative to pristine PET, sheets coated with AF reduced the initial bacterial adhesion (72h) and biofilm formation (30days) of B. subtilis by 27.6% and 68.7% and of E. coli by 89.2% and 93.8%, respectively. The comparable antibacterial and anti-biofilm efficacies were obtained by sheets with EF. The biofilm detachment was substantially facilitated from the AF, compared with the structural analogue without TFPDM (A). In this comprehensive study, the bacterial adhesion and subsequent biofilm formation were prevented by TFPDM-containing polymers effectively.
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26
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Meleppat RK, Shearwood C, Keey SL, Matham MV. Quantitative optical coherence microscopy for the in situ investigation of the biofilm. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:127002. [PMID: 27936266 DOI: 10.1117/1.jbo.21.12.127002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 11/17/2016] [Indexed: 05/04/2023]
Abstract
This paper explores the potential of optical coherence microscopy (OCM) for the <italic<in situ</italic< monitoring of biofilm growth. The quantitative imaging of the early developmental biology of a representative biofilm, <italic<Klebsiella pneumonia</italic< (KP-1), was performed using a swept source-based Fourier domain OCM system. The growth dynamics of the KP-1 biofilms and their transient response under perturbation was investigated using the enface visualization of microcolonies and their spatial localization. Furthermore, the optical density (OD) and planar density of the biofilms are calculated using an OCM technique and compared with OD and colony forming units measured using standard procedures via the sampling of the flow-cell effluent.
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Affiliation(s)
- Ratheesh Kumar Meleppat
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Christopher Shearwood
- Nanyang Technological University, Biological Process Laboratory, School of Mechanical and Aerospace Engineering, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Seah Leong Keey
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Murukeshan Vadakke Matham
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, 50 Nanyang Avenue, Singapore 639798, Singapore
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Liu S, Gunawan C, Barraud N, Rice SA, Harry EJ, Amal R. Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8954-8976. [PMID: 27479445 DOI: 10.1021/acs.est.6b00835] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In drinking water distribution systems (DWDS), biofilms are the predominant mode of microbial growth, with the presence of extracellular polymeric substance (EPS) protecting the biomass from environmental and shear stresses. Biofilm formation poses a significant problem to the drinking water industry as a potential source of bacterial contamination, including pathogens, and, in many cases, also affecting the taste and odor of drinking water and promoting the corrosion of pipes. This article critically reviews important research findings on biofilm growth in DWDS, examining the factors affecting their formation and characteristics as well as the various technologies to characterize and monitor and, ultimately, to control their growth. Research indicates that temperature fluctuations potentially affect not only the initial bacteria-to-surface attachment but also the growth rates of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria; ammonia-oxidizing bacteria, for example, grow more-developed biofilms at a typical summer temperature of 22 °C compared to 12 °C in fall, and the opposite occurs for the pathogenic Vibrio cholerae. Recent investigations have found the formation of thinner yet denser biofilms under high and turbulent flow regimes of drinking water, in comparison to the more porous and loosely attached biofilms at low flow rates. Furthermore, in addition to the rather well-known tendency of significant biofilm growth on corrosion-prone metal pipes, research efforts also found leaching of growth-promoting organic compounds from the increasingly popular use of polymer-based pipes. Knowledge of the unique microbial members of drinking water biofilms and, importantly, the influence of water characteristics and operational conditions on their growth can be applied to optimize various operational parameters to minimize biofilm accumulation. More-detailed characterizations of the biofilm population size and structure are now feasible with fluorescence microscopy (epifluorescence and CLSM imaging with DNA, RNA, EPS, and protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, thorough identification of microbial fingerprints in drinking water biofilms is achievable with DNA sequencing techniques (the 16S rRNA gene-based identification), which have revealed a prevalence of previously undetected bacterial members. Technologies are now moving toward in situ monitoring of biomass growth in distribution networks, including the development of optical fibers capable of differentiating biomass from chemical deposits. Taken together, management of biofilm growth in water distribution systems requires an integrated approach, starting from the treatment of water prior to entering the networks to the potential implementation of "biofilm-limiting" operational conditions and, finally, ending with the careful selection of available technologies for biofilm monitoring and control. For the latter, conventional practices, including chlorine-chloramine disinfection, flushing of DWDS, nutrient removal, and emerging technologies are discussed with their associated challenges.
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Affiliation(s)
| | - Cindy Gunawan
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
| | - Nicolas Barraud
- Department of Microbiology, Genetics of Biofilms Unit, Institut Pasteur , Paris 75015, France
| | - Scott A Rice
- The Singapore Centre for Environmental Life Sciences Engineering and School of Biological Sciences, Nanyang Technological University , 639798, Singapore
| | - Elizabeth J Harry
- ithree institute, University of Technology Sydney , Sydney, NSW 2007, Australia
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28
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Weiss N, Obied KETE, Kalkman J, Lammertink RG, van Leeuwen TG. Measurement of biofilm growth and local hydrodynamics using optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:3508-3518. [PMID: 27699116 PMCID: PMC5030028 DOI: 10.1364/boe.7.003508] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/16/2016] [Accepted: 07/29/2016] [Indexed: 05/08/2023]
Abstract
We report on localized and simultaneous measurement of biofilm growth and local hydrodynamics in a microfluidic channel using optical coherence tomography. We measure independently with high spatio-temporal resolution the longitudinal flow velocity component parallel to the imaging beam and the transverse flow velocity component perpendicular to the imaging beam. Based on the measured velocities we calculate the shear-rates in the flow channel. We show the relation between the measured biofilm structure and flow velocities as biofilm growth progresses over the course of 48 hours.
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Affiliation(s)
- Nicolás Weiss
- Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam,
The Netherlands
| | - Khalid El Tayeb El Obied
- Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede,
The Netherlands
| | - Jeroen Kalkman
- Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft,
The Netherlands
| | - Rob G.H. Lammertink
- Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede,
The Netherlands
| | - Ton G. van Leeuwen
- Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam,
The Netherlands
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Abstract
Bacteria have traditionally been studied as single-cell organisms. In laboratory settings, aerobic bacteria are usually cultured in aerated flasks, where the cells are considered essentially homogenous. However, in many natural environments, bacteria and other microorganisms grow in mixed communities, often associated with surfaces. Biofilms are comprised of surface-associated microorganisms, their extracellular matrix material, and environmental chemicals that have adsorbed to the bacteria or their matrix material. While this definition of a biofilm is fairly simple, biofilms are complex and dynamic. Our understanding of the activities of individual biofilm cells and whole biofilm systems has developed rapidly, due in part to advances in molecular, analytical, and imaging tools and the miniaturization of tools designed to characterize biofilms at the enzyme level, cellular level, and systems level.
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Shen Y, Huang C, Monroy GL, Janjaroen D, Derlon N, Lin J, Espinosa-Marzal R, Morgenroth E, Boppart SA, Ashbolt NJ, Liu WT, Nguyen TH. Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1779-87. [PMID: 26756120 PMCID: PMC5135099 DOI: 10.1021/acs.est.5b04653] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine- or free-chlorine-treated biofilms was 4 to 9 times higher than those before treatment. Meanwhile, the biofilm thickness decreased from 120 ± 8 μm to 93 ± 6-107 ± 11 μm. The increased surface stiffness and decreased biofilm thickness within the first month of disinfectant exposure was presumably due to the consumption of biomass. However, by the second to third month during disinfectant exposure, the biofilm mean stiffness showed a 2- to 4-fold decrease, and the biofilm thickness increased to 110 ± 7-129 ± 8 μm, suggesting that the biofilms adapted to disinfectant exposure. After three months of the disinfectant exposure process, the disinfected biofilms showed 2-5 times higher mean stiffness (as determined by AFM) and 6-13-fold higher ratios of protein over polysaccharide, as determined by differential staining and confocal laser scanning microscopy (CLSM), than the nondisinfected groundwater biofilms. However, the disinfected biofilms and nondisinfected biofilms showed statistically similar thicknesses (t test, p > 0.05), suggesting that long-term disinfection may not significantly remove net biomass. This study showed how biofilm mechanical and structural properties vary in response to a complex DWDS environment, which will contribute to further research on the risk assessment and control of biofilm-associated-pathogens in DWDS.
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Affiliation(s)
| | | | | | | | - Nicolas Derlon
- Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
| | | | | | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich , 8093 Zürich, Switzerland
| | | | - Nicholas J Ashbolt
- School of Public Health, University of Alberta , Edmonton, AB T6G 2G7 Canada
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31
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West S, Wagner M, Engelke C, Horn H. Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2015.09.047] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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Li C, Felz S, Wagner M, Lackner S, Horn H. Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography. BIORESOURCE TECHNOLOGY 2016; 200:128-36. [PMID: 26476614 DOI: 10.1016/j.biortech.2015.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 05/23/2023]
Abstract
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 images revealed comparable results with respect to average biofilm thickness and compartment filling degree before the carrier compartments were fully willed with biomass. However, 3D imaging with OCT was capable of visualizing and quantifying the heterogeneous structure of biofilms, which cannot be achieved using 2D imaging.
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Affiliation(s)
- Chunyan Li
- Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany
| | - Simon Felz
- Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany; Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Michael Wagner
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Susanne Lackner
- Urban Material Flow Management Technologies, Bauhaus-Institute for Infrastructure Solutions, Bauhaus University Weimar, Coudraystraße 7, 99421 Weimar, Germany
| | - Harald Horn
- Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany; DVGW Research Laboratories Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany.
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33
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Li C, Wagner M, Lackner S, Horn H. Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling. Biotechnol Bioeng 2015; 113:989-1000. [PMID: 26498328 DOI: 10.1002/bit.25868] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/13/2015] [Accepted: 10/19/2015] [Indexed: 11/09/2022]
Abstract
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 as well as the substrate distribution. The method allowed detailed analysis of the hydrodynamics and mass transfer characteristics at the micro-scale. Biofilm activity with respect to substrate fluxes was compared among different combinations of flow, substrate availability and biomass density. The combined approach revealed that higher substrate fluxes at heterogeneous biofilm surface under two conditions: pure diffusion and when high flow velocity along the biofilms surface renders the whole liquid-biofilm interface to be highly active. In-between the two conditions the substrate fluxes across the surface of smooth biofilm geometry were higher than that of the heterogeneous biofilms.
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Affiliation(s)
- Chunyan Li
- Chair of Water Chemistry, Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe, 76131, Germany
| | - Michael Wagner
- Chair of Water Chemistry, Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe, 76131, Germany.,Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Susanne Lackner
- Chair of Water Chemistry, Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe, 76131, Germany.,Urban Bioengineering for Resource Recovery, Bauhaus-Institute for Infrastructure Solutions, Bauhaus-Universityät Weimar, Weimar, Germany
| | - Harald Horn
- Chair of Water Chemistry, Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, Karlsruhe, 76131, Germany.
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34
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Rasmussen K, Reilly C, Li Y, Jones RS. Real-time imaging of anti-biofilm effects using CP-OCT. Biotechnol Bioeng 2015; 113:198-205. [PMID: 26156808 DOI: 10.1002/bit.25701] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/16/2015] [Accepted: 07/03/2015] [Indexed: 11/06/2022]
Abstract
The objective of this study was to develop a method to reliably and reproducibly assess the physical properties of in vitro multi-species plaque derived biofilms. A custom flow cell (FC) was designed to model oral cavity shear stresses on biofilms grown on hydroxyapatite (HA) discs. A finite-element program (ANSYS 13) modeled flow velocities and wall shear stresses on the interior 3D dimensions. For the experiment, 1% chlorhexidine (CHX), 5 M urea, and a 1× phosphate-buffered saline (PBS) were flown through the FC simulating oral rinsing. Near infrared cross-polarization optical coherence tomography (CP-OCT) non-destructively imaged the fluid immersed biofilms in real time (20 frames/s). During low flow, the swell of the biofilm caused from 5 M urea was quite pronounced increase in vertical dimension. Biofilms exposed to 1% CHX showed a slight collapse in the vertical dimension of the biofilm during low flow. During high flow/high sheer stress, the 5 M urea solution effectively removed the biofilm, while both 1% CHX and 1× PBS did not remove biofilms even under high velocity/shear stress conditions.
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Affiliation(s)
- Karin Rasmussen
- Department of Developmental and Surgical Sciences, Division of Pediatric Dentistry, School of Dentistry, University of Minnesota, 6-150C Moos Tower, 515 Delaware St. SE, Minneapolis, 55455, Minnesota
| | - Cavan Reilly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota
| | - Yuping Li
- Minnesota Dental Research Center for Biomaterials and Biomechanics, University of Minnesota School of Dentistry, Minneapolis, Minnesota
| | - Robert S Jones
- Department of Developmental and Surgical Sciences, Division of Pediatric Dentistry, School of Dentistry, University of Minnesota, 6-150C Moos Tower, 515 Delaware St. SE, Minneapolis, 55455, Minnesota.
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35
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Blauert F, Horn H, Wagner M. Time-resolved biofilm deformation measurements using optical coherence tomography. Biotechnol Bioeng 2015; 112:1893-905. [DOI: 10.1002/bit.25590] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Florian Blauert
- Chair of Water Chemistry and Water Technology; Karlsruhe Institute of Technology; Engler-Bunte-Ring 1 D-76131 Karlsruhe Germany
| | - Harald Horn
- Chair of Water Chemistry and Water Technology; Karlsruhe Institute of Technology; Engler-Bunte-Ring 1 D-76131 Karlsruhe Germany
| | - Michael Wagner
- Chair of Water Chemistry and Water Technology; Karlsruhe Institute of Technology; Engler-Bunte-Ring 1 D-76131 Karlsruhe Germany
- Institute of Functional Interfaces; Karlsruhe Institute of Technology; Eggenstein-Leopoldshafen Germany
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36
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Innovative techniques, sensors, and approaches for imaging biofilms at different scales. Trends Microbiol 2015; 23:233-42. [DOI: 10.1016/j.tim.2014.12.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/04/2014] [Accepted: 12/19/2014] [Indexed: 11/19/2022]
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37
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Monroy GL, Shelton RL, Nolan RM, Nguyen CT, Novak MA, Hill MC, McCormick DT, Boppart SA. Noninvasive depth-resolved optical measurements of the tympanic membrane and middle ear for differentiating otitis media. Laryngoscope 2015; 125:E276-82. [PMID: 25599652 DOI: 10.1002/lary.25141] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 11/17/2014] [Accepted: 12/15/2014] [Indexed: 12/22/2022]
Abstract
OBJECTIVE/HYPOTHESIS In this study, optical coherence tomography (OCT) is used to noninvasively and quantitatively determine tympanic membrane (TM) thickness and the presence and thickness of any middle-ear biofilm located behind the TM. These new metrics offer the potential to differentiate normal, acute, and chronic otitis media (OM) infections in pediatric subjects. STUDY DESIGN Case series with comparison group. METHODS The TM thickness of 34 pediatric subjects was acquired using a custom-built, handheld OCT system following a traditional otoscopic ear exam. RESULTS Overall thickness (TM and any associated biofilm) was shown to be statistically different for normal, acute, and chronic infection groups (normal-acute and normal-chronic: P value < 0.001; acute-chronic: P value = 0.0016). Almost all observed scans from the chronic group had an accompanying biofilm structure. When the thickness of the TM and biofilm were considered separately in chronic OM, the chronic TM thickness correlated with the normal group (P value = 0.68) yet was still distinct from the acute OM group (P value < 0.001), indicating that the TM in chronic OM returns to relatively normal thickness levels. CONCLUSION Identifying these physical changes in vivo provides new metrics for noninvasively and quantitatively differentiating normal, acute, and chronic OM. This new diagnostic information has the potential to assist physicians to more effectively and efficiently screen, manage, and refer patients based on quantitative data. LEVEL OF EVIDENCE 4.
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Affiliation(s)
- Guillermo L Monroy
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A
| | - Ryan L Shelton
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A
| | - Ryan M Nolan
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A
| | - Cac T Nguyen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A
| | - Michael A Novak
- Department of Surgery, College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Department of Otolaryngology, Urbana, Illinois, U.S.A
| | - Malcolm C Hill
- Department of Pediatrics, College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Department of Pediatrics, Urbana, Illinois, U.S.A
| | - Daniel T McCormick
- Carle Foundation Hospital, Urbana, Illinois, U.S.A.,Advanced MEMS, San Francisco, California, U.S.A
| | - Stephen A Boppart
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A.,Department of Internal Medicine, College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, U.S.A
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38
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Dreszer C, Wexler AD, Drusová S, Overdijk T, Zwijnenburg A, Flemming HC, Kruithof JC, Vrouwenvelder JS. In-situ biofilm characterization in membrane systems using Optical Coherence Tomography: formation, structure, detachment and impact of flux change. WATER RESEARCH 2014; 67:243-54. [PMID: 25282092 DOI: 10.1016/j.watres.2014.09.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 08/03/2014] [Accepted: 09/04/2014] [Indexed: 05/23/2023]
Abstract
Biofouling causes performance loss in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane operation for process and drinking water production. The development of biofilm formation, structure and detachment was studied in-situ, non-destructively with Optical Coherence Tomography (OCT) in direct relation with the hydraulic biofilm resistance and membrane performance parameters: transmembrane pressure drop (TMP) and feed-channel pressure drop (FCP). The objective was to evaluate the suitability of OCT for biofouling studies, applying a membrane biofouling test cell operated at constant crossflow velocity (0.1 m s(-1)) and permeate flux (20 L m(-2)h(-1)). In time, the biofilm thickness on the membrane increased continuously causing a decline in membrane performance. Local biofilm detachment was observed at the biofilm-membrane interface. A mature biofilm was subjected to permeate flux variation (20 to 60 to 20 L m(-2)h(-1)). An increase in permeate flux caused a decrease in biofilm thickness and an increase in biofilm resistance, indicating biofilm compaction. Restoring the original permeate flux did not completely restore the original biofilm parameters: After elevated flux operation the biofilm thickness was reduced to 75% and the hydraulic resistance increased to 116% of the original values. Therefore, after a temporarily permeate flux increase the impact of the biofilm on membrane performance was stronger. OCT imaging of the biofilm with increased permeate flux revealed that the biofilm became compacted, lost internal voids, and became more dense. Therefore, membrane performance losses were not only related to biofilm thickness but also to the internal biofilm structure, e.g. caused by changes in pressure. Optical Coherence Tomography proved to be a suitable tool for quantitative in-situ biofilm thickness and morphology studies which can be carried out non-destructively and in real-time in transparent membrane biofouling monitors.
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Affiliation(s)
- C Dreszer
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands; Biofilm Centre, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany
| | - A D Wexler
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | - S Drusová
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | - T Overdijk
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | - A Zwijnenburg
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | - H-C Flemming
- Biofilm Centre, University Duisburg-Essen, Universitätsstrasse 5, 45141 Essen, Germany
| | - J C Kruithof
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands
| | - J S Vrouwenvelder
- Wetsus, Centre of Excellence for Sustainable Water Technology, Agora 1, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands; Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands; King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal, Saudi Arabia.
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Le HND, Kim MS, Hwang J, Yang Y, Thainual PU, Kang JU, Kim DH. An average enumeration method of hyperspectral imaging data for quantitative evaluation of medical device surface contamination. BIOMEDICAL OPTICS EXPRESS 2014; 5:3613-3627. [PMID: 25360377 PMCID: PMC4206329 DOI: 10.1364/boe.5.003613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/05/2014] [Accepted: 09/05/2014] [Indexed: 06/04/2023]
Abstract
We propose a quantification method called Mapped Average Principal component analysis Score (MAPS) to enumerate the contamination coverage on common medical device surfaces. The method was adapted from conventional Principal Component Analysis (PCA) on non-overlapped regions of a full frame hyperspectral image to resolve the percentage of contamination from the substrate. The concept was proven by using a controlled contamination sample with artificial test soil and color simulating organic mixture, and was further validated using a bacterial system including biofilm on stainless steel surface. We also validate the results of MAPS with other statistical spectral analysis including Spectral Angle Mapper (SAM). The proposed method provides an alternative quantification method for hyperspectral imaging data, which can be easily implemented by basic PCA analysis.
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Affiliation(s)
- Hanh N. D. Le
- Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, M.D. 20993, USA
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, M.D. 21218, USA
| | - Moon S. Kim
- United States Department of Agriculture, 1400 Independence Ave., S.W, Washington, D.C. 20250, USA
| | - Jeeseong Hwang
- National Institute of Standards and Technology, 325 Broadway St., Boulder, C.O. 80305, USA
| | - Yi Yang
- Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, M.D. 20993, USA
| | - Paweena U Thainual
- Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, M.D. 20993, USA
| | - Jin U. Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, M.D. 21218, USA
| | - Do-Hyun Kim
- Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, M.D. 20993, USA
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Ajdaharian J, Dadkhah M, Sabokpey S, Biren-Fetz J, Chung NE, Wink C, Wilder-Smith P. Multimodality imaging of the effects of a novel dentifrice on oral biofilm. Lasers Surg Med 2014; 46:546-52. [PMID: 24916419 PMCID: PMC4140948 DOI: 10.1002/lsm.22265] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2014] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Oral biofilm formation and progression on the surface of the tooth can lead to advanced oral disease such as gingivitis. The purpose of this randomized, controlled, double-blinded study was to evaluate the effects of a novel dental gel on oral plaque biofilm using multimodal imaging techniques. MATERIALS AND METHODS Twenty-five subjects with moderate gingival inflammation (Löe and Silness Gingival Index ≥2) and pocket depths <4 were randomly assigned to brush twice daily for 21 days with the test or the control dental gel. In vivo multimodality in situ imaging was performed over a 3-week period using in vivo Optical Coherence Tomography (OCT) and Non-Linear Optical microscopy (NLOM). Plaque levels, gingival inflammation and gingival bleeding were also charted on days 0, 7, 14, and 21 using standard clinical indices. RESULTS After 3 weeks, OCT and NLOM images showed a macroscopic break-up of the plaque layer and smaller, fragmented residual deposits in the test group with no apparent changes in the pellicle. Biofilm was also reduced in the control group, but to a lesser degree with regard to thickness, continuity and surface area. Paralleling these imaging results, clinical indices were significantly improved in both groups (P < 0.05) and significantly lower in the test group (P < 0.05). CONCLUSION Both dental gels reduced oral biofilm with the test gel showing greater efficacy (P < 0.05) as determined by clinical and imaging parameters.
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Affiliation(s)
- Janet Ajdaharian
- Beckman Laser Institute, University of California, Irvine, California 92612
| | - Mohammad Dadkhah
- Beckman Laser Institute, University of California, Irvine, California 92612
| | - Sara Sabokpey
- Beckman Laser Institute, University of California, Irvine, California 92612
| | - John Biren-Fetz
- Beckman Laser Institute, University of California, Irvine, California 92612
| | - Na Eun Chung
- Beckman Laser Institute, University of California, Irvine, California 92612
| | - Cherie Wink
- Beckman Laser Institute, University of California, Irvine, California 92612
- School of Dental Hygiene, Concorde Career College, Garden Grove, California 92840
| | - Petra Wilder-Smith
- Beckman Laser Institute, University of California, Irvine, California 92612
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Berlowska J, Kregiel D, Ambroziak W. Physiological tests for yeast brewery cells immobilized on modified chamotte carrier. Antonie Van Leeuwenhoek 2013; 104:703-14. [PMID: 23887884 PMCID: PMC3824387 DOI: 10.1007/s10482-013-9978-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/16/2013] [Indexed: 11/30/2022]
Abstract
In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.
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Affiliation(s)
- Joanna Berlowska
- Institute of Fermentation Technology and Microbiology, Technical University of Lodz, ul. Wolczanska 171/173, 90-924, Lodz, Poland,
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Janjaroen D, Ling FQ, Monroy G, Derlon N, Morgenroth E, Boppart SA, Liu WT, Nguyen TH. Roles of ionic strength and biofilm roughness on adhesion kinetics of Escherichia coli onto groundwater biofilm grown on PVC surfaces. WATER RESEARCH 2013; 47:2531-42. [PMID: 23497979 PMCID: PMC3922059 DOI: 10.1016/j.watres.2013.02.032] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 05/22/2023]
Abstract
Mechanisms of Escherichia coli attachment on biofilms grown on PVC coupons were investigated. Biofilms were grown in CDC reactors using groundwater as feed solution over a period up to 27 weeks. Biofilm physical structure was characterized at the micro- and meso-scales using Scanning Electron Microscopy (SEM) and Optical Coherence Tomography (OCT), respectively. Microbial community diversity was analyzed with Terminal Restricted Fragment Length Polymorphism (T-RFLP). Both physical structure and microbial community diversity of the biofilms were shown to be changing from 2 weeks to 14 weeks, and became relatively stable after 16 weeks. A parallel plate flow chamber coupled with an inverted fluorescent microscope was also used to monitor the attachment of fluorescent microspheres and E. coli on clean PVC surfaces and biofilms grown on PVC surfaces for different ages. Two mechanisms of E. coli attachment were identified. The adhesion rate coefficients (kd) of E. coli on nascent PVC surfaces and 2-week biofilms increased with ionic strength. However, after biofilms grew for 8 weeks, the adhesion was found to be independent of solution chemistry. Instead, a positive correlation between kd and biofilm roughness as determined by OCT was obtained, indicating that the physical structure of biofilms could play an important role in facilitating the adhesion of E. coli cells.
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Affiliation(s)
- Dao Janjaroen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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Nguyen CT, Robinson SR, Jung W, Novak MA, Boppart SA, Allen JB. Investigation of bacterial biofilm in the human middle ear using optical coherence tomography and acoustic measurements. Hear Res 2013; 301:193-200. [PMID: 23588039 DOI: 10.1016/j.heares.2013.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 03/28/2013] [Accepted: 04/02/2013] [Indexed: 11/29/2022]
Abstract
Children with chronic otitis media (OM) often have conductive hearing loss which results in communication difficulties and requires surgical treatment. Recent studies have provided clinical evidence that there is a one-to-one correspondence between chronic OM and the presence of a bacterial biofilm behind the tympanic membrane (TM). Here we investigate the acoustic effects of bacterial biofilms, confirmed using optical coherence tomography (OCT), in adult ears. Non-invasive OCT images are collected to visualize the cross-sectional structure of the middle ear, verifying the presence of a biofilm behind the TM. Wideband measurements of acoustic reflectance and impedance (0.2-6 [kHz]) are used to study the acoustic properties of ears with confirmed bacterial biofilms. Compared to known acoustic properties of normal middle ears, each of the ears with a bacterial biofilm has an elevated power reflectance in the 1 to 3 [kHz] range, corresponding to an abnormally small resistance (real part of the impedance). These results provide assistance for the clinical diagnosis of a bacterial biofilm, which could lead to improved treatment of chronic middle ear infection and further understanding of the impact of chronic OM on conductive hearing loss. This article is part of a special issue entitled "MEMRO 2012".
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Affiliation(s)
- Cac T Nguyen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N Mathews Ave, Urbana, IL 61801, USA
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Zhu H, Isikman SO, Mudanyali O, Greenbaum A, Ozcan A. Optical imaging techniques for point-of-care diagnostics. LAB ON A CHIP 2013; 13:51-67. [PMID: 23044793 PMCID: PMC3510351 DOI: 10.1039/c2lc40864c] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Improving access to effective and affordable healthcare has long been a global endeavor. In this quest, the development of cost-effective and easy-to-use medical testing equipment that enables rapid and accurate diagnosis is essential to reduce the time and costs associated with healthcare services. To this end, point-of-care (POC) diagnostics plays a crucial role in healthcare delivery in both developed and developing countries by bringing medical testing to patients, or to sites near patients. As the diagnosis of a wide range of diseases, including various types of cancers and many endemics, relies on optical techniques, numerous compact and cost-effective optical imaging platforms have been developed in recent years for use at the POC. Here, we review the state-of-the-art optical imaging techniques that can have a significant impact on global health by facilitating effective and affordable POC diagnostics.
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Affiliation(s)
- Hongying Zhu
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Serhan O. Isikman
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Onur Mudanyali
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Alon Greenbaum
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
| | - Aydogan Ozcan
- Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA
- Bioengineering Department, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute (CNSI), University of California, Los Angeles, CA 90095, USA
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He W, Wang D, Ye Z, Qian W, Tao Y, Shi X, Liu L, Chen J, Qiu L, Wan P, Jia X, Li X, Gao C, Ma X, Wen B, Chen N, Li P, Ren Z, Lan L, Li S, Zuo Y, Zhang H, Ma L, Zhang Y, Li Z, Su W, Yang Q, Chen Q, Wang X, Ye Z, Chen JP, Loo WTY, Chow LWC, Yip AYS, Ng ELY, Cheung MNB, Wang Z. Application of a nanotechnology antimicrobial spray to prevent lower urinary tract infection: a multicenter urology trial. J Transl Med 2012; 10 Suppl 1:S14. [PMID: 23046566 PMCID: PMC3445864 DOI: 10.1186/1479-5876-10-s1-s14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background Catheter-associated urinary tract infection (CAUTI) is a common nosocomial device-associated infection. It is now recognized that the high infection rates were caused by the formation of biofilm on the surface of the catheters that decreases the susceptibility to antibiotics and results in anti-microbial resistance. In this study, we performed an in vitro test to explore the mechanism of biofilm formation and subsequently conducted a multi-center clinical trial to investigate the efficacy of CAUTI prevention with the application of JUC, a nanotechnology antimicrobial spray. Methods Siliconized latex urinary catheters were cut into fragments and sterilized by autoclaving. The sterilized sample fragments were randomly divided into the therapy and control group, whereby they were sprayed with JUC and distilled water respectively and dried before use. The experimental standard strains of Escherichia coli (E. coli) were isolated from the urine samples of patients. At 16 hours and 7 days of incubation, the samples were extracted for confocal laser scanning microscopy. A total of 1,150 patients were accrued in the clinical study. Patients were randomized according to the order of surgical treatment. The odd array of patients was assigned as the therapy group (JUC), and the even array of patients was assigned as the control group (normal saline). Results After 16 hours of culture, bacterial biofilm formed on the surface of sample fragments from the control group. In the therapy group, no bacterial biofilm formation was observed on the sample fragments. No significant increase in bacterial colony count was observed in the therapy group after 7 days of incubation. On the 7th day of catheterization, urine samples were collected for bacterial culture before extubation. Significant difference was observed in the incidence of bacteriuria between the therapy group and control group (4.52% vs. 13.04%, p < 0.001). Conclusions In this study, the effectiveness of JUC in preventing CAUTI in a hospital setting was demonstrated in both in vitro and clinical studies.
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Affiliation(s)
- Wei He
- School of Chinese Medicine, The University of Hong Kong, Hong Kong SAR
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Jung Y, Nichols AJ, Klein OJ, Roussakis E, Evans CL. Label-Free, Longitudinal Visualization of PDT Response In Vitro with Optical Coherence Tomography. Isr J Chem 2012; 52:728-744. [PMID: 23316088 PMCID: PMC3538822 DOI: 10.1002/ijch.201200009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A major challenge in creating and optimizing therapeutics in the fight against cancer is visualizing and understanding the microscale spatiotemporal treatment response dynamics that occur in patients. This is especially true for photodynamic therapy (PDT), where therapeutic optimization relies on understanding the interplay between factors such as photosensitizer localization and uptake, in addition to light dose and delivery rate. In vitro 3D culture systems that recapitulate many of the biological features of human disease are powerful platforms for carrying out detailed studies on PDT response and resistance. Current techniques for visualizing these models, however, often lack accuracy due to the perturbative nature of the sample preparation, with light attenuation complicating the study of intact models. Optical coherence tomography (OCT) is an ideal method for the long-term, non-perturbative study of in vitro models and their response to PDT. Monitoring the response of 3D models to PDT by time-lapse OCT methods promises to provide new perspectives and open the way to cancer treatment methodologies that can be translated towards the clinic.
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Affiliation(s)
- Yookyung Jung
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (USA)
| | - Alexander J. Nichols
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (USA)
- Harvard University, Program in Biophysics, Cambridge, Massachusetts (USA)
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts (USA)
| | - Oliver J. Klein
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (USA)
| | - Emmanuel Roussakis
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (USA)
| | - Conor L. Evans
- Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (USA)
- Harvard University, Program in Biophysics, Cambridge, Massachusetts (USA)
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Noninvasive in vivo optical detection of biofilm in the human middle ear. Proc Natl Acad Sci U S A 2012; 109:9529-34. [PMID: 22645342 DOI: 10.1073/pnas.1201592109] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Otitis media (OM), a middle-ear infection, is the most common childhood illness treated by pediatricians. If inadequately treated, OM can result in long-term chronic problems persisting into adulthood. Children with chronic OM or recurrent OM often have conductive hearing loss and communication difficulties and require surgical treatment. Tympanostomy tube insertion, the placement of a small drainage tube in the tympanic membrane (TM), is the most common surgical procedure performed in children under general anesthesia. Recent clinical studies have shown evidence of a direct correspondence between chronic OM and the presence of a bacterial biofilm within the middle ear. Biofilms are typically very thin and cannot be recognized using a regular otoscope. Here we report the use of optical coherent ranging techniques to noninvasively assess the middle ear to detect and quantify biofilm microstructure. This study involves adults with chronic OM, which is generally accepted as a biofilm-related disease. Based on more than 18,537 optical ranging scans and 742 images from 13 clinically infected patients and 7 normal controls using clinical findings as the gold standard, all middle ears with chronic OM showed evidence of biofilms, and all normal ears did not. Information on the presence of a biofilm, along with its structure and response to antibiotic treatment, will not only provide a better fundamental understanding of biofilm formation, growth, and eradication in the middle ear, but also may provide much-needed quantifiable data to enable early detection and quantitative longitudinal treatment monitoring of middle-ear biofilms responsible for chronic OM.
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Lenton P, Rudney J, Chen R, Fok A, Aparicio C, Jones RS. Imaging in vivo secondary caries and ex vivo dental biofilms using cross-polarization optical coherence tomography. Dent Mater 2012; 28:792-800. [PMID: 22578989 DOI: 10.1016/j.dental.2012.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 02/21/2012] [Accepted: 04/12/2012] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Conventional diagnostic methods frequently detect only late stage enamel demineralization under composite resin restorations. The objective of this study is to examine the subsurface tooth-composite interface and to assess for the presence of secondary caries in pediatric patients using a novel Optical Coherence Tomography System with an intraoral probe. METHODS A newly designed intraoral cross polarization swept source optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the enamel-composite interfaces in vivo. Twenty-two pediatric subjects were recruited with either recently placed or long standing composite restorations in their primary teeth. To better understand how bacterial biofilms cause demineralization at the interface, we also used the intraoral CP-OCT system to assess ex vivo bacterial biofilm growth on dental composites. RESULTS As a positive control, cavitated secondary carious interfaces showed a 18.2dB increase (p<0.001), or over 1-2 orders of magnitude higher, scattering than interfaces associated with recently placed composite restorations. Several long standing composite restorations, which appeared clinically sound, had a marked increase in scattering than recently placed restorations. This suggests the ability of CP-OCT to assess interfacial degradation such as early secondary caries prior to cavitation. CP-OCT was also able to image ex vivo biofilms on dental composites and assess their thickness. SIGNIFICANCE This paper shows that CP-OCT imaging using a beam splitter based design can examine the subsurface interface of dental composites in human subjects. Furthermore, the probe dimensions and acquisition speed of the CP-OCT system allowed for analysis of caries development in children.
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Affiliation(s)
- Pat Lenton
- Department of Developmental and Surgical Sciences, University of Minnesota, 515 Delaware Street, Minneapolis, MN 55455, USA
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Chen R, Rudney J, Aparicio C, Fok A, Jones RS. Quantifying dental biofilm growth using cross-polarization optical coherence tomography. Lett Appl Microbiol 2012; 54:537-42. [PMID: 22435929 DOI: 10.1111/j.1472-765x.2012.03243.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Quantifying the ex vivo growth of complex multispecies dental biofilms using cross-polarization 1310-nm optical coherence tomography (CP-OCT) system was investigated. METHODS AND RESULTS Bacterial microcosms, which were derived from plaque samples of paediatric subjects, were incubated in a biofilm reactor system containing discs of different dental materials for 72 h with daily sucrose pulsing (5×). CP-OCT analysis of biofilm mass was validated with crystal violet (CV) assays at various growth stages of these complex biofilms. CP-OCT was able to filter out the back-reflected signals of water layers in the hydrated biofilm and allowed for direct biofilm quantification. The overall depth-resolved scattering intensity of the biofilm showed very strong positive correlation with CV assay quantification (Spearman's ρ = 0.92) during the growth phase of the biofilm. CONCLUSION CP-OCT was able to quantify the mass of the biofilm by measuring the overall depth-resolved scattering of the biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY CP-OCT has the ability to nondestructively monitor biofilm growth and elucidate the growth characteristics of these microcosms on different dental material compositions.
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Affiliation(s)
- R Chen
- School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
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