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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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Ghosh UU, Ali H, Ghosh R, Kumar A. Bacterial streamers as colloidal systems: Five grand challenges. J Colloid Interface Sci 2021; 594:265-278. [PMID: 33765646 DOI: 10.1016/j.jcis.2021.02.102] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/21/2022]
Abstract
Bacteria can thrive in biofilms, which are intricately organized communities with cells encased in a self-secreted matrix of extracellular polymeric substances (EPS). Imposed hydrodynamic stresses can transform this active colloidal dispersion of bacteria and EPS into slender thread-like entities called streamers. In this perspective article, the reader is introduced to the world of such deformable 'bacteria-EPS' composites that are a subclass of the generic flow-induced colloidal structures. While bacterial streamers have been shown to form in a variety of hydrodynamic conditions (turbulent and creeping flows), its abiotic analogues have only been demonstrated in low Reynolds number (Re < 1) particle-laden polymeric flows. Streamers are relevant to a variety of situations ranging from natural formations in caves and river beds to clogging of biomedical devices and filtration membranes. A critical review of the relevant biophysical aspects of streamer formation phenomena and unique attributes of its material behavior are distilled to unveil five grand scientific challenges. The coupling between colloidal hydrodynamics, device geometry and streamer formation are highlighted.
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Affiliation(s)
- Udita U Ghosh
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India
| | - Hessein Ali
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA
| | - Ranajay Ghosh
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, USA.
| | - Aloke Kumar
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India.
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3
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Khalid S, Gao A, Wang G, Chu PK, Wang H. Tuning surface topographies on biomaterials to control bacterial infection. Biomater Sci 2021; 8:6840-6857. [PMID: 32812537 DOI: 10.1039/d0bm00845a] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microbial contamination and subsequent formation of biofilms frequently cause failure of surgical implants and a good understanding of the bacteria-surface interactions is vital to the design and safety of biomaterials. In this review, the physical and chemical factors that are involved in the various stages of implant-associated bacterial infection are described. In particular, topographical modification strategies that have been employed to mitigate bacterial adhesion via topographical mechanisms are summarized and discussed comprehensively. Recent advances have improved our understanding about bacteria-surface interactions and have enabled biomedical engineers and researchers to develop better and more effective antibacterial surfaces. The related interdisciplinary efforts are expected to continue in the quest for next-generation medical devices to attain the ultimate goal of improved clinical outcomes and reduced number of revision surgeries.
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Affiliation(s)
- Saud Khalid
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
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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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Harper CE, Hernandez CJ. Cell biomechanics and mechanobiology in bacteria: Challenges and opportunities. APL Bioeng 2020; 4:021501. [PMID: 32266323 PMCID: PMC7113033 DOI: 10.1063/1.5135585] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
Physical forces play a profound role in the survival and function of all known forms of life. Advances in cell biomechanics and mechanobiology have provided key insights into the physiology of eukaryotic organisms, but much less is known about the roles of physical forces in bacterial physiology. This review is an introduction to bacterial mechanics intended for persons familiar with cells and biomechanics in mammalian cells. Bacteria play a major role in human health, either as pathogens or as beneficial commensal organisms within the microbiome. Although bacteria have long been known to be sensitive to their mechanical environment, understanding the effects of physical forces on bacterial physiology has been limited by their small size (∼1 μm). However, advancements in micro- and nano-scale technologies over the past few years have increasingly made it possible to rigorously examine the mechanical stress and strain within individual bacteria. Here, we review the methods currently used to examine bacteria from a mechanical perspective, including the subcellular structures in bacteria and how they differ from those in mammalian cells, as well as micro- and nanomechanical approaches to studying bacteria, and studies showing the effects of physical forces on bacterial physiology. Recent findings indicate a large range in mechanical properties of bacteria and show that physical forces can have a profound effect on bacterial survival, growth, biofilm formation, and resistance to toxins and antibiotics. Advances in the field of bacterial biomechanics have the potential to lead to novel antibacterial strategies, biotechnology approaches, and applications in synthetic biology.
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Affiliation(s)
- Christine E. Harper
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
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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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Aggarwal S, Stewart PS, Hozalski RM. Biofilm Cohesive Strength as a Basis for Biofilm Recalcitrance: Are Bacterial Biofilms Overdesigned? Microbiol Insights 2016; 8:29-32. [PMID: 26819559 PMCID: PMC4718087 DOI: 10.4137/mbi.s31444] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 11/05/2022] Open
Abstract
Bacterial biofilms are highly resistant to common antibacterial treatments, and several physiological explanations have been offered to explain the recalcitrant nature of bacterial biofilms. Herein, a biophysical aspect of biofilm recalcitrance is being reported on. While engineering structures are often overdesigned with a factor of safety (FOS) usually under 10, experimental measurements of biofilm cohesive strength suggest that the FOS is on the order of thousands. In other words, bacterial biofilms appear to be designed to withstand extreme forces rather than typical or average loads. In scenarios requiring the removal or control of unwanted biofilms, this emphasizes the importance of considering strategies for structurally weakening the biofilms in conjunction with bacterial inactivation.
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Affiliation(s)
- Srijan Aggarwal
- Department of Civil and Environmental Engineering, University of Alaska, Fairbanks, AK, USA
| | - Philip S Stewart
- Center for Biofilm Engineering, Montana State University, Bozeman, MT, USA
| | - Raymond M Hozalski
- Department of Civil, Environmental and Geo-engineering, University of Minnesota, Minneapolis, MN, USA
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Douarche C, Allain JM, Raspaud E. Bacillus subtilis Bacteria Generate an Internal Mechanical Force within a Biofilm. Biophys J 2015; 109:2195-202. [PMID: 26588577 PMCID: PMC4656877 DOI: 10.1016/j.bpj.2015.10.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/04/2023] Open
Abstract
A key issue in understanding why biofilms are the most prevalent mode of bacterial life is the origin of the degree of resistance and protection that bacteria gain from self-organizing into biofilm communities. Our experiments suggest that their mechanical properties are a key factor. Experiments on pellicles, or floating biofilms, of Bacillus subtilis showed that while they are multiplying and secreting extracellular substances, bacteria create an internal force (associated with a -80±25 Pa stress) within the biofilms, similar to the forces that self-equilibrate and strengthen plants, organs, and some engineered buildings. Here, we found that this force, or stress, is associated with growth-induced pressure. Our observations indicate that due to such forces, biofilms spread after any cut or ablation by up to 15-20% of their initial size. The force relaxes over very short timescales (tens of milliseconds). We conclude that this force helps bacteria to shape the biofilm, improve its mechanical resistance, and facilitate its invasion and self-repair.
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Affiliation(s)
- Carine Douarche
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Orsay Cedex, France
| | - Jean-Marc Allain
- Laboratoire de Mécanique des Solides, CNRS-UMR 7649, École Polytechnique, Palaiseau, France
| | - Eric Raspaud
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Orsay Cedex, France.
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Stewart EJ, Ganesan M, Younger JG, Solomon MJ. Artificial biofilms establish the role of matrix interactions in staphylococcal biofilm assembly and disassembly. Sci Rep 2015; 5:13081. [PMID: 26272750 PMCID: PMC4536489 DOI: 10.1038/srep13081] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/16/2015] [Indexed: 01/21/2023] Open
Abstract
We demonstrate that the microstructural and mechanical properties of bacterial biofilms can be created through colloidal self-assembly of cells and polymers, and thereby link the complex material properties of biofilms to well understood colloidal and polymeric behaviors. This finding is applied to soften and disassemble staphylococcal biofilms through pH changes. Bacterial biofilms are viscoelastic, structured communities of cells encapsulated in an extracellular polymeric substance (EPS) comprised of polysaccharides, proteins, and DNA. Although the identity and abundance of EPS macromolecules are known, how these matrix materials interact with themselves and bacterial cells to generate biofilm morphology and mechanics is not understood. Here, we find that the colloidal self-assembly of Staphylococcus epidermidis RP62A cells and polysaccharides into viscoelastic biofilms is driven by thermodynamic phase instability of EPS. pH conditions that induce phase instability of chitosan produce artificial S. epidermidis biofilms whose mechanics match natural S. epidermidis biofilms. Furthermore, pH-induced solubilization of the matrix triggers disassembly in both artificial and natural S. epidermidis biofilms. This pH-induced disassembly occurs in biofilms formed by five additional staphylococcal strains, including three clinical isolates. Our findings suggest that colloidal self-assembly of cells and matrix polymers produces biofilm viscoelasticity and that biofilm control strategies can exploit this mechanism.
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Affiliation(s)
- Elizabeth J. Stewart
- Department of Chemical Engineering, University of Michigan, 3074 H.H. Dow, 2300 Hayward Street, Ann Arbor, MI 48109
| | - Mahesh Ganesan
- Department of Chemical Engineering, University of Michigan, 3074 H.H. Dow, 2300 Hayward Street, Ann Arbor, MI 48109
| | - John G. Younger
- Department of Emergency Medicine, University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Ann Arbor, MI 48109
| | - Michael J. Solomon
- Department of Chemical Engineering, University of Michigan, 3074 H.H. Dow, 2300 Hayward Street, Ann Arbor, MI 48109
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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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van der Sluis L, Boutsioukis C, Jiang LM, Macedo R, Verhaagen B, Versluis M. Root Canal Irrigation. SPRINGER SERIES ON BIOFILMS 2015. [DOI: 10.1007/978-3-662-47415-0_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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He Y, Peterson BW, Jongsma MA, Ren Y, Sharma PK, Busscher HJ, van der Mei HC. Stress relaxation analysis facilitates a quantitative approach towards antimicrobial penetration into biofilms. PLoS One 2013; 8:e63750. [PMID: 23723995 PMCID: PMC3664570 DOI: 10.1371/journal.pone.0063750] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/26/2013] [Indexed: 12/19/2022] Open
Abstract
Biofilm-related infections can develop everywhere in the human body and are rarely cleared by the host immune system. Moreover, biofilms are often tolerant to antimicrobials, due to a combination of inherent properties of bacteria in their adhering, biofilm mode of growth and poor physical penetration of antimicrobials through biofilms. Current understanding of biofilm recalcitrance toward antimicrobial penetration is based on qualitative descriptions of biofilms. Here we hypothesize that stress relaxation of biofilms will relate with antimicrobial penetration. Stress relaxation analysis of single-species oral biofilms grown in vitro identified a fast, intermediate and slow response to an induced deformation, corresponding with outflow of water and extracellular polymeric substances, and bacterial re-arrangement, respectively. Penetration of chlorhexidine into these biofilms increased with increasing relative importance of the slow and decreasing importance of the fast relaxation element. Involvement of slow relaxation elements suggests that biofilm structures allowing extensive bacterial re-arrangement after deformation are more open, allowing better antimicrobial penetration. Involvement of fast relaxation elements suggests that water dilutes the antimicrobial upon penetration to an ineffective concentration in deeper layers of the biofilm. Next, we collected biofilms formed in intra-oral collection devices bonded to the buccal surfaces of the maxillary first molars of human volunteers. Ex situ chlorhexidine penetration into two weeks old in vivo formed biofilms followed a similar dependence on the importance of the fast and slow relaxation elements as observed for in vitro formed biofilms. This study demonstrates that biofilm properties can be derived that quantitatively explain antimicrobial penetration into a biofilm.
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Affiliation(s)
- Yan He
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Brandon W. Peterson
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Marije A. Jongsma
- Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Yijin Ren
- Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Prashant K. Sharma
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Henk J. Busscher
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
| | - Henny C. van der Mei
- Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands
- * E-mail:
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Ganesan M, Stewart EJ, Szafranski J, Satorius A, Younger JG, Solomon MJ. Molar mass, entanglement, and associations of the biofilm polysaccharide of Staphylococcus epidermidis. Biomacromolecules 2013; 14:1474-81. [PMID: 23540609 PMCID: PMC3676870 DOI: 10.1021/bm400149a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Biofilms are microbial communities that are characterized by the presence of a viscoelastic extracellular polymeric substance (EPS). Studies have shown that polysaccharides, along with proteins and DNA, are a major constituent of the EPS and play a dominant role in mediating its microstructure and rheological properties. Here, we investigate the possibility of entanglements and associative complexes in solutions of extracellular polysaccharide intercellular adhesin (PIA) extracted from Staphylococcus epidermidis biofilms. We report that the weight average molar mass and radius of gyration of PIA isolates are 2.01×10(5)±1200 g/mol and 29.2±1.2 nm, respectively. The coil overlap concentration, c*, was thus determined to be (32±4)×10(-4) g/mL. Measurements of the in situ concentration of PIA (cPIA,biofilm) was found to be (10±2)×10(-4) g/mL.Thus, cPIA,biofilm
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Affiliation(s)
- Mahesh Ganesan
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48105
| | | | - Jacob Szafranski
- Department of Emergency Medicine, University of Michigan, Ann Arbor, MI 48105
| | - Ashley Satorius
- Department of Emergency Medicine, University of Michigan, Ann Arbor, MI 48105
| | - John G. Younger
- Department of Emergency Medicine, University of Michigan, Ann Arbor, MI 48105
| | - Michael J. Solomon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48105
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Abstract
Wrinkled morphology is a distinctive phenotype observed in mature biofilms produced by a great number of bacteria. Here we study the formation of macroscopic structures (wrinkles and folds) observed during the maturation of Bacillus subtilis pellicles in relation to their mechanical response. We show how the mechanical buckling instability can explain their formation. By performing simple tests, we highlight the role of confining geometry and growth in determining the symmetry of wrinkles. We also experimentally demonstrate that the pellicles are soft elastic materials for small deformations induced by a tensile device. The wrinkled structures are then described by using the equations of elastic plates, which include the growth process as a simple parameter representing biomass production. This growth controls buckling instability, which triggers the formation of wrinkles. We also describe how the structure of ripples is modified when capillary effects are dominant. Finally, the experiments performed on a mutant strain indicate that the presence of an extracellular matrix is required to maintain a connective and elastic pellicle.
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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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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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