1
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Zhang Y, Young P, Traini D, Li M, Ong HX, Cheng S. Challenges and current advances in in vitro biofilm characterization. Biotechnol J 2023; 18:e2300074. [PMID: 37477959 DOI: 10.1002/biot.202300074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/22/2023]
Abstract
Biofilms are structured communities of bacterial cells encased in a self-produced polymeric matrix, which develop over time and exhibit temporal responses to stimuli from internal biological processes or external environmental changes. They can be detrimental, threatening public health and causing economic loss, while they also play beneficial roles in ecosystem health, biotechnology processes, and industrial settings. Biofilms express extreme heterogeneity in their physical properties and structural composition, resulting in critical challenges in understanding them comprehensively. The lack of detailed knowledge of biofilms and their phenotypes has deterred significant progress in developing strategies to control their negative impacts and take advantage of their beneficial applications. A range of in vitro models and characterization tools have been developed and used to study biofilm growth and, specifically, to investigate the impact of environmental and growth factors on their development. This review article discusses the existing knowledge of biofilm properties and explains how external factors, such as flow condition, surface, interface, and host factor, may impact biofilm growth. The limitations of current tools, techniques, and in vitro models that are currently used for biofilms are also presented.
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Affiliation(s)
- Ye Zhang
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
| | - Paul Young
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
- Department of Marketing, Macquarie Business School, Macquarie University, Sydney, New South Wales, Australia
| | - Daniela Traini
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Ming Li
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia
| | - Hui Xin Ong
- Woolcock Institute of Medical Research, Sydney, New South Wales, Australia
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Shaokoon Cheng
- School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia
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2
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Competition between growth and shear stress drives intermittency in preferential flow paths in porous medium biofilms. Proc Natl Acad Sci U S A 2022; 119:e2122202119. [PMID: 35858419 PMCID: PMC9335220 DOI: 10.1073/pnas.2122202119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Bacteria in porous media, such as soils, aquifers, and filters, often form surface-attached communities known as biofilms. Biofilms are affected by fluid flow through the porous medium, for example, for nutrient supply, and they, in turn, affect the flow. A striking example of this interplay is the strong intermittency in flow that can occur when biofilms nearly clog the porous medium. Intermittency manifests itself as the rapid opening and slow closing of individual preferential flow paths (PFPs) through the biofilm-porous medium structure, leading to continual spatiotemporal rearrangement. The drastic changes to the flow and mass transport induced by intermittency can affect the functioning and efficiency of natural and industrial systems. Yet, the mechanistic origin of intermittency remains unexplained. Here, we show that the mechanism driving PFP intermittency is the competition between microbial growth and shear stress. We combined microfluidic experiments quantifying Bacillus subtilis biofilm formation and behavior in synthetic porous media for different pore sizes and flow rates with a mathematical model accounting for flow through the biofilm and biofilm poroelasticity to reveal the underlying mechanisms. We show that the closing of PFPs is driven by microbial growth, controlled by nutrient mass flow. Opposing this, we find that the opening of PFPs is driven by flow-induced shear stress, which increases as a PFP becomes narrower due to microbial growth, causing biofilm compression and rupture. Our results demonstrate that microbial growth and its competition with shear stresses can lead to strong temporal variability in flow and transport conditions in bioclogged porous media.
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3
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Savorana G, Słomka J, Stocker R, Rusconi R, Secchi E. A microfluidic platform for characterizing the structure and rheology of biofilm streamers. SOFT MATTER 2022; 18:3878-3890. [PMID: 35535650 PMCID: PMC9131465 DOI: 10.1039/d2sm00258b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Biofilm formation is the most successful survival strategy for bacterial communities. In the biofilm lifestyle, bacteria embed themselves in a self-secreted matrix of extracellular polymeric substances (EPS), which acts as a shield against mechanical and chemical insults. When ambient flow is present, this viscoelastic scaffold can take a streamlined shape, forming biofilm filaments suspended in flow, called streamers. Streamers significantly disrupt the fluid flow by causing rapid clogging and affect transport in aquatic environments. Despite their relevance, the structural and rheological characterization of biofilm streamers is still at an early stage. In this work, we present a microfluidic platform that allows the reproducible growth of biofilm streamers in controlled physico-chemical conditions and the characterization of their biochemical composition, morphology, and rheology in situ. We employed isolated micropillars as nucleation sites for the growth of single biofilm streamers under the continuous flow of a diluted bacterial suspension. By combining fluorescent staining of the EPS components and epifluorescence microscopy, we were able to characterize the biochemical composition and morphology of the streamers. Additionally, we optimized a protocol to perform hydrodynamic stress tests in situ, by inducing controlled variations of the fluid shear stress exerted on the streamers by the flow. Thus, the reproducibility of the formation process and the testing protocol make it possible to perform several consistent experimental replicates that provide statistically significant information. By allowing the systematic investigation of the role of biochemical composition on the structure and rheology of streamers, this platform will advance our understanding of biofilm formation.
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Affiliation(s)
- Giovanni Savorana
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Jonasz Słomka
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roman Stocker
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roberto Rusconi
- Department of Biomedical Sciences, Humanitas University, 20072, Pieve Emanuele, MI, Italy
- IRCCS Humanitas Research Hospital, 20089, Rozzano, MI, Italy
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
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Deng T, DePaoli D, Bégin L, Jia N, Torres de Oliveira L, Côté DC, Vincent WF, Greener J. Versatile Microfluidic Platform for Automated Live-Cell Hyperspectral Imaging Applied to Cold Climate Cyanobacterial Biofilms. Anal Chem 2021; 93:8764-8773. [PMID: 34133116 DOI: 10.1021/acs.analchem.0c05446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microfluidic bioanalytical platforms are driving discoveries from synthetic biology to the health sciences. In this work, we present a platform for in vivo live-cell imaging and automated species detection in mixed cyanobacterial biofilms from cold climate environments. Using a multimodal microscope with custom optics applied to a chip with six parallel growth channels, we monitored biofilm dynamics via continuous imaging at natural irradiance levels. Machine learning algorithms were applied to the collected hyperspectral images for automatic segmentation of mixed-species biofilms into individual species of cyanobacteria with similar filamentous morphology. The coupling of microfluidic technology with modern multimodal imaging and computer vision systems provides a versatile platform for the study of cause-and-effect scenarios of cyanobacterial biofilms, which are important elements of many ecosystems, including lakes and rivers of the polar regions.
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Affiliation(s)
- Tianyang Deng
- Département de chimie, Faculté des sciences et de génie, Université Laval, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada
| | - Damon DePaoli
- Département de Physique, Génie Physique et Optique, Université Laval, Québec, G1V 0A6, Canada
- CERVO Brain Research Center, Québec G1J 2G3, Canada
| | - Ludovick Bégin
- Département de Physique, Génie Physique et Optique, Université Laval, Québec, G1V 0A6, Canada
- CERVO Brain Research Center, Québec G1J 2G3, Canada
| | - Nan Jia
- Département de chimie, Faculté des sciences et de génie, Université Laval, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada
| | - Leon Torres de Oliveira
- Département de chimie, Faculté des sciences et de génie, Université Laval, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada
| | - Daniel C Côté
- Département de Physique, Génie Physique et Optique, Université Laval, Québec, G1V 0A6, Canada
- CERVO Brain Research Center, Québec G1J 2G3, Canada
| | - Warwick F Vincent
- Centre d'études nordiques (CEN), Takuvik Joint International Laboratory & Département de biologie, Université Laval, 2405 rue de la Terrasse, Québec, Québec G1V 0A6, Canada
| | - Jesse Greener
- Département de chimie, Faculté des sciences et de génie, Université Laval, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada
- CHU de Québec, Centre de recherche, Université Laval, 10 rue de l'Espinay, Québec, Québec G1L 3L5, Canada
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5
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Boudarel H, Mathias JD, Blaysat B, Grédiac M. In situ tracking of microbeads for the detection of biofilm formation. Biotechnol Bioeng 2020; 118:1244-1261. [PMID: 33300127 DOI: 10.1002/bit.27648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/09/2020] [Accepted: 11/21/2020] [Indexed: 12/30/2022]
Abstract
In this study, we utilize the free motion of beads incorporated in bacterial suspension to investigate the behavior of the medium surrounding the beads during biofilm formation. The use of imaging techniques such as digital image correlation enables tracking of the movement of beads, which serve as markers in the processed images. This method is applied to detect and characterize biofilm formation. The main originality of this study lies in characterizing the evolution of the typology of bead movements during biofilm formation. The aim is to identify bead behaviors that represent the start of biofilm formation. By observing inert bead movements introduced into the bacterial environment, changes in trajectory typologies are detected and appear to be related to sessile bacterial activity, bacterial hindrance, and adhesion or formation of extracellular material. We use our approach to discriminate between the presence or absence of antibiotics mixed with bacteria and to assess their effectiveness. The results highlight the potential of our approach as nondestructive tracking of biofilm dynamics over time based on optical microscope images.
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Affiliation(s)
- Héloïse Boudarel
- CNRS, SIGMA Clermont, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Jean-Denis Mathias
- INRAE, UR LISC, Centre de Clermont-Ferrand, Université Clermont Auvergne, Aubière, France
| | - Benoît Blaysat
- CNRS, SIGMA Clermont, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Michel Grédiac
- CNRS, SIGMA Clermont, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
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6
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Charlton SGV, White MA, Jana S, Eland LE, Jayathilake PG, Burgess JG, Chen J, Wipat A, Curtis TP. Regulating, Measuring, and Modeling the Viscoelasticity of Bacterial Biofilms. J Bacteriol 2019; 201:e00101-19. [PMID: 31182499 PMCID: PMC6707926 DOI: 10.1128/jb.00101-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Biofilms occur in a broad range of environments under heterogeneous physicochemical conditions, such as in bioremediation plants, on surfaces of biomedical implants, and in the lungs of cystic fibrosis patients. In these scenarios, biofilms are subjected to shear forces, but the mechanical integrity of these aggregates often prevents their disruption or dispersal. Biofilms' physical robustness is the result of the multiple biopolymers secreted by constituent microbial cells which are also responsible for numerous biological functions. A better understanding of the role of these biopolymers and their response to dynamic forces is therefore crucial for understanding the interplay between biofilm structure and function. In this paper, we review experimental techniques in rheology, which help quantify the viscoelasticity of biofilms, and modeling approaches from soft matter physics that can assist our understanding of the rheological properties. We describe how these methods could be combined with synthetic biology approaches to control and investigate the effects of secreted polymers on the physical properties of biofilms. We argue that without an integrated approach of the three disciplines, the links between genetics, composition, and interaction of matrix biopolymers and the viscoelastic properties of biofilms will be much harder to uncover.
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Affiliation(s)
- Samuel G V Charlton
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael A White
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Saikat Jana
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Lucy E Eland
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - J Grant Burgess
- School of Natural & Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anil Wipat
- Interdisciplinary Computing & Complex BioSystems Research Group, School of Computing, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom
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7
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Liou HC, Sabba F, Packman AI, Wells G, Balogun O. Nondestructive characterization of soft materials and biofilms by measurement of guided elastic wave propagation using optical coherence elastography. SOFT MATTER 2019; 15:575-586. [PMID: 30601536 DOI: 10.1039/c8sm01902a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biofilms are soft multicomponent biological materials composed of microbial communities attached to surfaces. Despite the crucial relevance of biofilms to diverse industrial, medical, and environmental applications, the mechanical properties of biofilms are understudied. Moreover, most of the available techniques for the characterization of biofilm mechanical properties are destructive. Here, we detail a model-based approach developed to characterize the viscoelastic properties of soft materials and bacterial biofilms based on experimental data obtained using the nondestructive dynamic optical coherence elastography (OCE) technique. The model predicted the frequency- and geometry-dependent propagation velocities of elastic waves in a soft viscoelastic plate supported by a rigid substratum. Our numerical calculations suggest that the dispersion curves of guided waves recorded in thin soft plates by the dynamic OCE technique are dominated by guided waves, whose phase velocities depend on the viscoelastic properties and plate thickness. The numerical model was validated against experimental measurements in agarose phantom samples with different thicknesses and concentrations. The model was then used to interpret guided wave dispersion curves obtained by the OCE technique in bacterial biofilms developed in a rotating annular reactor, which allowed the quantitative characterization of biofilm shear modulus and viscosity. This study is the first to employ measurements of elastic wave propagation to characterize biofilms, and it provides a novel framework combining a theoretical model and an experimental approach for studying the relationship between the biofilm internal physical structure and mechanical properties.
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Affiliation(s)
- Hong-Cin Liou
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Fabrizio Sabba
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Aaron I Packman
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - George Wells
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Oluwaseyi Balogun
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA and Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
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8
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Pousti M, Zarabadi MP, Abbaszadeh Amirdehi M, Paquet-Mercier F, Greener J. Microfluidic bioanalytical flow cells for biofilm studies: a review. Analyst 2019; 144:68-86. [PMID: 30394455 DOI: 10.1039/c8an01526k] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bacterial biofilms are among the oldest and most prevalent multicellular life forms on Earth and are increasingly relevant in research areas related to industrial fouling, medicine and biotechnology. The main hurdles to obtaining definitive experimental results include time-varying biofilm properties, structural and chemical heterogeneity, and especially their strong sensitivity to environmental cues. Therefore, in addition to judicious choice of measurement tools, a well-designed biofilm study requires strict control over experimental conditions, more so than most chemical studies. Due to excellent control over a host of physiochemical parameters, microfluidic flow cells have become indispensable in microbiological studies. Not surprisingly, the number of lab-on-chip studies focusing on biofilms and other microbiological systems with expanded analytical capabilities has expanded rapidly in the past decade. In this paper, we comprehensively review the current state of microfluidic bioanalytical research applied to bacterial biofilms and offer a perspective on new approaches that are expected to drive continued advances in this field.
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Affiliation(s)
- Mohammad Pousti
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec City, Québec G1 V 0A6, Canada
| | - Mir Pouyan Zarabadi
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec City, Québec G1 V 0A6, Canada
| | - Mehran Abbaszadeh Amirdehi
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec City, Québec G1 V 0A6, Canada
| | - François Paquet-Mercier
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec City, Québec G1 V 0A6, Canada
| | - Jesse Greener
- Département de chimie, Faculté des sciences et de génie, Université Laval, Québec City, Québec G1 V 0A6, Canada and CHU de Quebec Research Centre, Laval University, 10 rue de l'Espinay, Quebec City, (QC) G1L 3L5, Canada
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9
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Towards standardized mechanical characterization of microbial biofilms: analysis and critical review. NPJ Biofilms Microbiomes 2018; 4:17. [PMID: 30131867 PMCID: PMC6102240 DOI: 10.1038/s41522-018-0062-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 02/05/2023] Open
Abstract
Developing reliable anti-biofilm strategies or efficient biofilm-based bioprocesses strongly depends on having a clear understanding of the mechanisms underlying biofilm development, and knowledge of the relevant mechanical parameters describing microbial biofilm behavior. Many varied mechanical testing methods are available to assess these parameters. The mechanical properties thus identified can then be used to compare protocols such as antibiotic screening. However, the lack of standardization in both mechanical testing and the associated identification methods for a given microbiological goal remains a blind spot in the biofilm community. The pursuit of standardization is problematic, as biofilms are living structures, i.e., both complex and dynamic. Here, we review the main available methods for characterizing the mechanical properties of biofilms through the lens of the relationship linking experimental testing to the identification of mechanical parameters. We propose guidelines for characterizing biofilms according to microbiological objectives that will help the reader choose an appropriate test and a relevant identification method for measuring any given mechanical parameter. The use of a common methodology for the mechanical characterization of biofilms will enable reliable analysis and comparison of microbiological protocols needed for improvement of engineering process and screening.
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10
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Thomen P, Robert J, Monmeyran A, Bitbol AF, Douarche C, Henry N. Bacterial biofilm under flow: First a physical struggle to stay, then a matter of breathing. PLoS One 2017; 12:e0175197. [PMID: 28403171 PMCID: PMC5389662 DOI: 10.1371/journal.pone.0175197] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 03/22/2017] [Indexed: 02/02/2023] Open
Abstract
Bacterial communities attached to surfaces under fluid flow represent a widespread lifestyle of the microbial world. Through shear stress generation and molecular transport regulation, hydrodynamics conveys effects that are very different by nature but strongly coupled. To decipher the influence of these levers on bacterial biofilms immersed in moving fluids, we quantitatively and simultaneously investigated physicochemical and biological properties of the biofilm. We designed a millifluidic setup allowing to control hydrodynamic conditions and to monitor biofilm development in real time using microscope imaging. We also conducted a transcriptomic analysis to detect a potential physiological response to hydrodynamics. We discovered that a threshold value of shear stress determined biofilm settlement, with sub-piconewton forces sufficient to prevent biofilm initiation. As a consequence, distinct hydrodynamic conditions, which set spatial distribution of shear stress, promoted distinct colonization patterns with consequences on the growth mode. However, no direct impact of mechanical forces on biofilm growth rate was observed. Consistently, no mechanosensing gene emerged from our differential transcriptomic analysis comparing distinct hydrodynamic conditions. Instead, we found that hydrodynamic molecular transport crucially impacts biofilm growth by controlling oxygen availability. Our results shed light on biofilm response to hydrodynamics and open new avenues to achieve informed design of fluidic setups for investigating, engineering or fighting adherent communities.
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Affiliation(s)
- Philippe Thomen
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 8237, Laboratoire Jean Perrin, Paris, France
| | - Jérôme Robert
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 8237, Laboratoire Jean Perrin, Paris, France
| | - Amaury Monmeyran
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 8237, Laboratoire Jean Perrin, Paris, France
| | - Anne-Florence Bitbol
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 8237, Laboratoire Jean Perrin, Paris, France
| | - Carine Douarche
- Université Paris Sud, UMR 8502, Laboratoire de Physique des Solides, Orsay, France
| | - Nelly Henry
- Sorbonne Universités, UPMC Univ Paris 06 & CNRS, UMR 8237, Laboratoire Jean Perrin, Paris, France
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11
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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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12
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Greener J, Parvinzadeh Gashti M, Eslami A, Zarabadi MP, Taghavi SM. A microfluidic method and custom model for continuous, non-intrusive biofilm viscosity measurements under different nutrient conditions. BIOMICROFLUIDICS 2016; 10:064107. [PMID: 27965730 PMCID: PMC5116028 DOI: 10.1063/1.4968522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 11/09/2016] [Indexed: 05/24/2023]
Abstract
Straight, low-aspect ratio micro flow cells are used to support biofilm attachment and preferential accumulation at the short side-wall, which progressively reduces the effective channel width. The biofilm shifts downstream at measurable velocities under the imposed force from the constant laminar co-flowing nutrient stream. The dynamic behaviour of the biofilm viscosity is modeled semi-analytically, based on experimental measurements of biofilm dimensions and velocity as inputs. The technique advances the study of biofilm mechanical properties by strongly limiting biases related to non-Newtonian biofilm properties (e.g., shear dependent viscosity) with excellent time resolution. To demonstrate the proof of principle, young Pseudomonas sp. biofilms were analyzed under different nutrient concentrations and constant micro-flow conditions. The striking results show that large initial differences in biofilm viscosities grown under different nutrient concentrations become nearly identical in less than one day, followed by a continuous thickening process. The technique verifies that in 50 h from inoculation to early maturation stages, biofilm viscosity could grow by over 2 orders of magnitude. The approach opens the way for detailed studies of mechanical properties under a wide variety of physiochemical conditions, such as ionic strength, temperature, and shear stress.
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Affiliation(s)
- J Greener
- Department of Chemistry, Université Laval , 1045 Ave. de la Médecine, Québec, Québec G1V 0A6, Canada
| | - M Parvinzadeh Gashti
- Department of Chemistry, Université Laval , 1045 Ave. de la Médecine, Québec, Québec G1V 0A6, Canada
| | - A Eslami
- Department of Chemical Engineering, Université Laval , Québec, Québec G1V 0A6, Canada
| | - M P Zarabadi
- Department of Chemistry, Université Laval , 1045 Ave. de la Médecine, Québec, Québec G1V 0A6, Canada
| | - S M Taghavi
- Department of Chemical Engineering, Université Laval , Québec, Québec G1V 0A6, Canada
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13
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Schlafer S, Meyer RL. Confocal microscopy imaging of the biofilm matrix. J Microbiol Methods 2016; 138:50-59. [PMID: 26979645 DOI: 10.1016/j.mimet.2016.03.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/29/2016] [Accepted: 03/02/2016] [Indexed: 11/28/2022]
Abstract
The extracellular matrix is an integral part of microbial biofilms and an important field of research. Confocal laser scanning microscopy is a valuable tool for the study of biofilms, and in particular of the biofilm matrix, as it allows real-time visualization of fully hydrated, living specimens. Confocal microscopes are held by many research groups, and a number of methods for qualitative and quantitative imaging of the matrix have emerged in recent years. This review provides an overview and a critical discussion of techniques used to visualize different matrix compounds, to determine the concentration of solutes and the diffusive properties of the biofilm matrix.
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Affiliation(s)
- Sebastian Schlafer
- Department of Dentistry, HEALTH, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark.
| | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Science and Technology, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Bioscience, Science and Technology, Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark.
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14
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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: 46] [Impact Index Per Article: 5.8] [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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15
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Kinetics of Pseudomonas veronii 2E biofilm development under different nutritional conditions for a proper bioreactor design. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2015.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Parvinzadeh Gashti M, Bellavance J, Kroukamp O, Wolfaardt G, Taghavi SM, Greener J. Live-streaming: Time-lapse video evidence of novel streamer formation mechanism and varying viscosity. BIOMICROFLUIDICS 2015; 9:041101. [PMID: 26339304 PMCID: PMC4529438 DOI: 10.1063/1.4928296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 07/29/2015] [Indexed: 05/12/2023]
Abstract
Time-lapse videos of growing biofilms were analyzed using a background subtraction method, which removed camouflaging effects from the heterogeneous field of view to reveal evidence of streamer formation from optically dense biofilm segments. In addition, quantitative measurements of biofilm velocity and optical density, combined with mathematical modeling, demonstrated that streamer formation occurred from mature, high-viscosity biofilms. We propose a streamer formation mechanism by sudden partial detachment, as opposed to continuous elongation as observed in other microfluidic studies. Additionally, streamer formation occurred in straight microchannels, as opposed to serpentine or pseudo-porous channels, as previously reported.
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Affiliation(s)
| | | | - Otini Kroukamp
- Department of Chemistry and Biology, Ryerson University , Toronto, Canada
| | - Gideon Wolfaardt
- Department of Microbiology, Stellenbosch University , Stellenbosch, South Africa
| | | | - Jesse Greener
- Département de Chimie, Université Laval , Québec, Canada
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17
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A novel method for rheological characterization of biofouling layers developing in Membrane Bioreactors (MBR). J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.02.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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18
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Peterson BW, He Y, Ren Y, Zerdoum A, Libera MR, Sharma PK, van Winkelhoff AJ, Neut D, Stoodley P, van der Mei HC, Busscher HJ. Viscoelasticity of biofilms and their recalcitrance to mechanical and chemical challenges. FEMS Microbiol Rev 2015; 39:234-45. [PMID: 25725015 PMCID: PMC4398279 DOI: 10.1093/femsre/fuu008] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We summarize different studies describing mechanisms through which bacteria in a biofilm mode of growth resist mechanical and chemical challenges. Acknowledging previous microscopic work describing voids and channels in biofilms that govern a biofilms response to such challenges, we advocate a more quantitative approach that builds on the relation between structure and composition of materials with their viscoelastic properties. Biofilms possess features of both viscoelastic solids and liquids, like skin or blood, and stress relaxation of biofilms has been found to be a corollary of their structure and composition, including the EPS matrix and bacterial interactions. Review of the literature on viscoelastic properties of biofilms in ancient and modern environments as well as of infectious biofilms reveals that the viscoelastic properties of a biofilm relate with antimicrobial penetration in a biofilm. In addition, also the removal of biofilm from surfaces appears governed by the viscoelasticity of a biofilm. Herewith, it is established that the viscoelasticity of biofilms, as a corollary of structure and composition, performs a role in their protection against mechanical and chemical challenges. Pathways are discussed to make biofilms more susceptible to antimicrobials by intervening with their viscoelasticity, as a quantifiable expression of their structure and composition. Recalcitrance of biofilms against mechanical and chemical challenges has been looked at for ages from a microbiological perspective, but an approach based on viscoelastic properties of biofilms yields new insights in this recalcitrance.
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Affiliation(s)
- Brandon W Peterson
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Yan He
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands University of Groningen and University Medical Center Groningen, Department of Orthodontics, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Yijin Ren
- University of Groningen and University Medical Center Groningen, Department of Orthodontics, Hanzeplein 1, 9700 RB Groningen, The Netherlands
| | - Aidan Zerdoum
- Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030, Hoboken, New Jersey, USA
| | - Matthew R Libera
- Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, NJ 07030, Hoboken, New Jersey, USA
| | - Prashant K Sharma
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Arie-Jan van Winkelhoff
- University of Groningen and University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Anatonius Deusinglaan 1, 9713 AV Groningen, The Netherlands University of Groningen and University Medical Center Groningen, Department of Medical Microbiology, Hanzeplein 1, 9700 RB, Groningen, The Netherlands
| | - Danielle Neut
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Paul Stoodley
- Departments of Microbial Infection and Immunity and Orthopedics, Center for Microbial Interface Biology, The Ohio State University, 460 West 12th Avenue, Columbus, OH 43210, USA National Centre for Advanced Tribology at Southampton (nCATS), Engineering Sciences, University of Southampton, SO17 1BJ, UK
| | - Henny C van der Mei
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Henk J Busscher
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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19
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Bridier A, Briandet R, Bouchez T, Jabot F. A model-based approach to detect interspecific interactions during biofilm development. BIOFOULING 2014; 30:761-771. [PMID: 24963685 DOI: 10.1080/08927014.2014.923409] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A model-based approach was developed to detect interspecific interactions during biofilm development. This approach relied on the comparison of experimental data with a simple null model of biofilm growth dynamics where individual species grew independently of one another, except that they competed for space. Such a model was directly parameterized with a 4D confocal image series of biofilms and then used as a null model to detect interspecific interactions between pairs of bacterial species. This approach was tested in two bispecific competitive trials. In the first trial, the progressive exclusion of Pseudomonas fluorescens by Pseudomonas putida appeared to be due solely to the different intrinsic growth rates of the two strains. In contrast, modelling results suggested the presence of interference competition between Pseudomonas aeruginosa and P. putida in mixed biofilms. The authors' approach enables the detection of ecologically relevant interactions which constitute a prerequisite to building a comprehensive view of the dynamics and functioning of spatially structured bacterial communities.
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20
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Limbert G, Bryan R, Cotton R, Young P, Hall-Stoodley L, Kathju S, Stoodley P. On the mechanics of bacterial biofilms on non-dissolvable surgical sutures: a laser scanning confocal microscopy-based finite element study. Acta Biomater 2013; 9:6641-52. [PMID: 23376125 DOI: 10.1016/j.actbio.2013.01.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 12/18/2012] [Accepted: 01/17/2013] [Indexed: 12/17/2022]
Abstract
Biofilms are bacterial communities encapsulated within a self-secreted extracellular polymeric substance and are responsible for a wide range of chronic medical device related infections. Understanding and addressing the conditions that lead to the attachment and detachment of biofilms from biomedical surfaces (orthopaedic implants, sutures, intravenous catheters, cardio-vascular stents) has the potential to identify areas of the device that might be more prone to infection and predict how and when biofilms might dislodge. In this study, an integrated software methodology was devised to create image-based microscopic finite element models of real biofilm colonies of Staphylococcus aureus attached to a fragment of surgical suture. The goal was to predict how deformation of the suture may lead to the potential detachment of biofilm colonies by solving the equations of continuum mechanics using the finite element method for various loading cases. Tension, torsion and bending of the biomaterial structure were simulated, demonstrating that small strains in the suture can produce surface shear stresses sufficient to trigger the sliding of biofilms over the suture surface. Applications of this technique to other medical devices are discussed.
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Affiliation(s)
- G Limbert
- National Centre for Advanced Tribology at Southampton (nCATS), Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.
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21
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Galy O, Latour-Lambert P, Zrelli K, Ghigo JM, Beloin C, Henry N. Mapping of bacterial biofilm local mechanics by magnetic microparticle actuation. Biophys J 2013; 103:1400-8. [PMID: 22995513 DOI: 10.1016/j.bpj.2012.07.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 07/02/2012] [Accepted: 07/02/2012] [Indexed: 11/28/2022] Open
Abstract
Most bacteria live in the form of adherent communities forming three-dimensional material anchored to artificial or biological surfaces, with profound impact on many human activities. Biofilms are recognized as complex systems but their physical properties have been mainly studied from a macroscopic perspective. To determine biofilm local mechanical properties, reveal their potential heterogeneity, and investigate their relation to molecular traits, we have developed a seemingly new microrheology approach based on magnetic particle infiltration in growing biofilms. Using magnetic tweezers, we achieved what was, to our knowledge, the first three-dimensional mapping of the viscoelastic parameters on biofilms formed by the bacterium Escherichia coli. We demonstrate that its mechanical profile may exhibit elastic compliance values spread over three orders of magnitude in a given biofilm. We also prove that heterogeneity strongly depends on external conditions such as growth shear stress. Using strains genetically engineered to produce well-characterized cell surface adhesins, we show that the mechanical profile of biofilm is exquisitely sensitive to the expression of different surface appendages such as F pilus or curli. These results provide a quantitative view of local mechanical properties within intact biofilms and open up an additional avenue for elucidating the emergence and fate of the different microenvironments within these living materials.
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Affiliation(s)
- Olivier Galy
- Institut Curie, Centre de Recherche, Paris, France
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22
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Guélon T, Hunter R, Mathias J, Deffuant G. Homogenization ofPseudomonas aeruginosaPAO1 biofilms visualized by freeze-substitution electron microscopy. Biotechnol Bioeng 2013; 110:1405-18. [DOI: 10.1002/bit.24805] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 11/08/2012] [Accepted: 11/28/2012] [Indexed: 11/09/2022]
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23
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Ehret AE, Böl M. Modelling mechanical characteristics of microbial biofilms by network theory. J R Soc Interface 2012; 10:20120676. [PMID: 23034354 DOI: 10.1098/rsif.2012.0676] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this contribution, we present a constitutive model to describe the mechanical behaviour of microbial biofilms based on classical approaches in the continuum theory of polymer networks. Although the model is particularly developed for the well-studied biofilms formed by mucoid Pseudomonas aeruginosa strains, it could easily be adapted to other biofilms. The basic assumption behind the model is that the network of extracellular polymeric substances can be described as a superposition of worm-like chain networks, each connected by transient junctions of a certain lifetime. Several models that were applied to biofilms previously are included in the presented approach as special cases, and for small shear strains, the governing equations are those of four parallel Maxwell elements. Rheological data given in the literature are very adequately captured by the proposed model, and the simulated response for a series of compression tests at large strains is in good qualitative agreement with reported experimental behavior.
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Affiliation(s)
- Alexander E Ehret
- Institute of Solid Mechanics, Technische Universita¨t Braunschweig, 38106 Braunschweig, Germany
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24
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Böl M, Ehret AE, Bolea Albero A, Hellriegel J, Krull R. Recent advances in mechanical characterisation of biofilm and their significance for material modelling. Crit Rev Biotechnol 2012; 33:145-71. [DOI: 10.3109/07388551.2012.679250] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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25
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Rusconi R, Lecuyer S, Autrusson N, Guglielmini L, Stone HA. Secondary flow as a mechanism for the formation of biofilm streamers. Biophys J 2011; 100:1392-9. [PMID: 21402020 DOI: 10.1016/j.bpj.2011.01.065] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 01/30/2011] [Accepted: 01/31/2011] [Indexed: 10/18/2022] Open
Abstract
In most environments, such as natural aquatic systems, bacteria are found predominantly in self-organized sessile communities known as biofilms. In the presence of a significant flow, mature multispecies biofilms often develop into long filamentous structures called streamers, which can greatly influence ecosystem processes by increasing transient storage and cycling of nutrients. However, the interplay between hydrodynamic stresses and streamer formation is still unclear. Here, we show that suspended thread-like biofilms steadily develop in zigzag microchannels with different radii of curvature. Numerical simulations of a low-Reynolds-number flow around these corners indicate the presence of a secondary vortical motion whose intensity is related to the bending angle of the turn. We demonstrate that the formation of streamers is directly proportional to the intensity of the secondary flow around the corners. In addition, we show that a model of an elastic filament in a two-dimensional corner flow is able to explain how the streamers can cross fluid streamlines and connect corners located at the opposite sides of the channel.
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Affiliation(s)
- Roberto Rusconi
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
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26
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27
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Aggarwal S, Hozalski RM. Determination of biofilm mechanical properties from tensile tests performed using a micro-cantilever method. BIOFOULING 2010; 26:479-486. [PMID: 20390563 DOI: 10.1080/08927011003793080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recently, a micro-cantilever method was introduced for measuring the ultimate tensile strength of intact bacterial biofilms. Herein, is reported the analysis of the video files from the testing of a 4-day-old Staphylococcus epidermidis biofilm to determine the elastic modulus, toughness, and failure strain. Elastic modulus (1270+/-280 Pa) was within the range of previously reported values (17-6000 Pa). The high failure strains (240+/-16%) indicate the substantial ductility of bacterial biofilms. In addition, the toughness of the biofilm sample was determined from the area under the stress-strain plot (2.8+/-0.44 kJ m(-3)). Thus, it was demonstrated that the micro-cantilever test video files can be used for the determination of other mechanical property parameters besides ultimate tensile strength.
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Affiliation(s)
- Srijan Aggarwal
- Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55455-0220, USA
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