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Zhang W, Qian L, He B, Gong X, Zhang G. Mechanism Insights of Antibacterial Surfaces Coated with Dead Probiotics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17632-17643. [PMID: 38033279 DOI: 10.1021/acs.langmuir.3c01818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.
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Affiliation(s)
- Weixiong Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
| | - Lu Qian
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
| | - Bingen He
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
| | - Xiangjun Gong
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou 510640, P. R. China
| | - Guangzhao Zhang
- Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P. R. China
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Huang C, Clark GG, Zaki FR, Won J, Ning R, Boppart SA, Elbanna AE, Nguyen TH. Effects of phosphate and silicate on stiffness and viscoelasticity of mature biofilms developed with simulated drinking water. BIOFOULING 2023; 39:36-46. [PMID: 36847486 PMCID: PMC10065970 DOI: 10.1080/08927014.2023.2177538] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/19/2023] [Accepted: 02/02/2023] [Indexed: 05/21/2023]
Abstract
Biofilms, a porous matrix of cells aggregated with extracellular polymeric substances under the influence of chemical constituents in the feed water, can develop a viscoelastic response to mechanical stresses. In this study, the roles of phosphate and silicate, common additives in corrosion control and meat processing, on the stiffness, viscoelasticity, porous structure networks, and chemical properties of biofilm were investigated. Three-year biofilms on PVC coupons were grown from sand-filtered groundwater with or without one of the non-nutrient (silicate) or nutrient additives (phosphate or phosphate blends). Compared with non-nutrient additives, the phosphate and phosphate-blend additives led to a biofilm with the lowest stiffness, most viscoelastic, and more porous structure, including more connecting throats with greater equivalent radii. The phosphate-based additives also led to more organic species in the biofilm matrix than the silicate additive did. This work demonstrated that nutrient additives could promote biomass accumulation but also reduce mechanical stability.
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Gemma G. Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Farzana R. Zaki
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
| | - Jungeun Won
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
| | - Runsen Ning
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, 306 North Wright Street, Urbana, Illinois 61801, USA
| | - Ahmed E. Elbanna
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Thanh H. Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
- 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, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
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3
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Ma X, Liu Z, Zeng W, Lin T, Tian X, Cheng X. Crack patterns of drying dense bacterial suspensions. SOFT MATTER 2022; 18:5239-5248. [PMID: 35771131 DOI: 10.1039/d2sm00012a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Drying of bacterial suspensions is frequently encountered in a plethora of natural and engineering processes. However, the evaporation-driven mechanical instabilities of dense consolidating bacterial suspensions have not been explored heretofore. Here, we report the formation of two different crack patterns of drying suspensions of Escherichia coli (E. coli) with distinct motile behaviors. Circular cracks are observed for wild-type E. coli with active swimming, whereas spiral-like cracks form for immotile bacteria. Using the elastic fracture mechanics and the poroelastic theory, we show that the formation of the circular cracks is determined by the tensile nature of the radial drying stress once the cracks are initiated by the local order structure of bacteria due to their collective swimming. Our study demonstrates the link between the microscopic swimming behaviors of individual bacteria and the mechanical instabilities and macroscopic pattern formation of drying bacterial films. The results shed light on the dynamics of active matter in a drying process and provide useful information for understanding various biological processes associated with drying bacterial suspensions.
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Affiliation(s)
- Xiaolei Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Zhengyang Liu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Wei Zeng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
- College of Life Science and Technology, Guangxi University, Nanning 530004, Guangxi, China
| | - Tianyi Lin
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Xin Tian
- Department of Physics & Astronomy, University of Wyoming, Laramie, WY 82071, USA
| | - Xiang Cheng
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
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Vladkova TG, Monov DM, Akuzov DT, Ivanova IA, Gospodinova D. Comparative Study of the Marinobacter hydrocarbonoclasticus Biofilm Formation on Antioxidants Containing Siloxane Composite Coatings. MATERIALS 2022; 15:ma15134530. [PMID: 35806655 PMCID: PMC9267624 DOI: 10.3390/ma15134530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/22/2022] [Accepted: 06/22/2022] [Indexed: 02/05/2023]
Abstract
No systematic study of antioxidant containing coatings and their anti-biofilm action has been reported so far. The utilization of antioxidants in protective coatings to inhibit marine biofilm formation is a current challenge. The aim of this preliminary study was to prepare, characterize and compare the efficiency of low adhesive siloxane composite coatings equally loaded with different antioxidants against mono-species biofilms formation. Most often participating in the marine biofilms formation, Marinobacter hydrocarbonoclasticus was the test bacterium. Both the biofilm covered surface area (BCSA) and corrected total cell fluorescence (CTCF) (by fluorescent microscopy) were selected as the parameters for quantification of the biofilm after 1 h and 4 h incubation. Differing extents of altered surface characteristics (physical-chemical; physical-mechanical) and the specific affection of M. hydrocarbonoclasticus biofilm formation in both reduction and stimulation, were found in the studied antioxidant containing coatings, depending on the chemical nature of the used antioxidant. It was concluded that not all antioxidants reduce mono-species biofilm formation; antioxidant chemical reactivity stipulates the formation of an altered vulcanization network of the siloxane composites and thus microbial adhesion which influences the surface characteristics of the vulcanized coatings; and low surface energy combined with a low indentation elastic modulus are probably pre-requisites of low microbial adhesion.
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Affiliation(s)
- Todorka G. Vladkova
- Department of Polymer Engineering, Faculty of Chemical Technology, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria;
- Correspondence: ; Tel.: +359-887-839-374
| | - Deyan M. Monov
- Faculty of Biology, Sofia University Saint Kliment Ohridski, 1164 Sofia, Bulgaria; (D.M.M.); (I.A.I.)
| | - Danail T. Akuzov
- Department of Polymer Engineering, Faculty of Chemical Technology, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria;
| | - Iliana A. Ivanova
- Faculty of Biology, Sofia University Saint Kliment Ohridski, 1164 Sofia, Bulgaria; (D.M.M.); (I.A.I.)
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5
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Hoogenkamp MA, Brandt BW, Laheij AMGA, de Soet JJ, Crielaard W. The microbiological load and microbiome of the Dutch dental unit; 'please, hold your breath'. WATER RESEARCH 2021; 200:117205. [PMID: 34058484 DOI: 10.1016/j.watres.2021.117205] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/09/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
Dental unit water systems are prone to biofilm formation. During use of the dental unit, clumps of biofilm slough off and can subsequently be aerosolized and inhaled by both patient and staff, potentially causing infections. The aim of this study was to determine the microbial load and microbiome of dental unit water, in the Netherlands, and the factors influencing these parameters. In total, 226 dental units were sampled and heterotrophic plate counts (HPC) were determined on the traditional effluent sample. Of all dental units, 61% exceeded the recommended microbiological guidelines of 100 colony forming units per milliliter. In addition, the microbiome, with additional q-PCR analysis for specific species, was determined on an effluent sample taken immediately after an overnight stagnancy period, in which the biofilm is in its relaxed state. These relaxed biofilm samples showed that each dental unit had a unique microbiome. Legionella spp., amoeba and fungi were found in 71%, 43% and 98% of all units, respectively. The presence of amoeba was positively associated with nine bacterial biomarkers and correlated positively with bacterial and fungal DNA and Legionella spp. concentrations, but not with HPC. Only when adhering to disinfection protocols, statistically significant effects on the microbial load and microbiome were seen. The relaxed biofilm sample, in combination with molecular techniques gives better insight in the presence of opportunistic pathogens when compared to the heterotrophic plate counts. Infection control measures should focus on biofilm analysis and control in order to guarantee patient safety.
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Affiliation(s)
- Michel A Hoogenkamp
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
| | - Bernd W Brandt
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Alexa M G A Laheij
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Oral Medicine, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Johannes J de Soet
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Wim Crielaard
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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6
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Bhagwat G, O'Connor W, Grainge I, Palanisami T. Understanding the Fundamental Basis for Biofilm Formation on Plastic Surfaces: Role of Conditioning Films. Front Microbiol 2021; 12:687118. [PMID: 34248907 PMCID: PMC8267902 DOI: 10.3389/fmicb.2021.687118] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/26/2021] [Indexed: 12/26/2022] Open
Abstract
Conditioning films (CFs) are surface coatings formed by the adsorption of biomolecules from the surrounding environment that can modify the material-specific surface properties and precedes the attachment of microorganisms. Hence, CFs are a biologically relevant identity that could govern the behavior and fate of microplastics in the aquatic environment. In the present study, polyethylene terephthalate (PET) and polylactic acid (PLA) plastic cards were immersed in natural seawater to allow the formation of CFs. The changes in the surface roughness after 24 h were investigated by atomic force microscopy (AFM), and the surface changes were visualized by scanning electron microscopy (SEM). The global elemental composition of the conditioned surface was investigated by energy dispersive spectroscopy (EDS). Results indicated that marine conditioning of PET and PLA samples for 24 h resulted in an increase of ∼11 and 31% in the average surface roughness, respectively. SEM images revealed the attachment of coccoid-shaped bacterial cells on the conditioned surfaces, and the accumulation of salts of sodium and phosphate-containing precipitates was revealed through the EDS analysis. The results indicate that the increase in surface roughness due to conditioning is linked to a material’s hydrophilicity leading to a rapid attachment of bacteria on the surfaces. Further investigations into the CFs can unfold crucial knowledge surrounding the plastic-microbe interaction that has implications for medical, industrial, and environmental research.
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Affiliation(s)
- Geetika Bhagwat
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Wayne O'Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, NSW, Australia
| | - Ian Grainge
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Thava Palanisami
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, NSW, Australia
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7
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Bhagwat G, O'Connor W, Grainge I, Palanisami T. Understanding the Fundamental Basis for Biofilm Formation on Plastic Surfaces: Role of Conditioning Films. Front Microbiol 2021. [PMID: 34248907 DOI: 10.3389/fmicb.2021.687118/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Conditioning films (CFs) are surface coatings formed by the adsorption of biomolecules from the surrounding environment that can modify the material-specific surface properties and precedes the attachment of microorganisms. Hence, CFs are a biologically relevant identity that could govern the behavior and fate of microplastics in the aquatic environment. In the present study, polyethylene terephthalate (PET) and polylactic acid (PLA) plastic cards were immersed in natural seawater to allow the formation of CFs. The changes in the surface roughness after 24 h were investigated by atomic force microscopy (AFM), and the surface changes were visualized by scanning electron microscopy (SEM). The global elemental composition of the conditioned surface was investigated by energy dispersive spectroscopy (EDS). Results indicated that marine conditioning of PET and PLA samples for 24 h resulted in an increase of ∼11 and 31% in the average surface roughness, respectively. SEM images revealed the attachment of coccoid-shaped bacterial cells on the conditioned surfaces, and the accumulation of salts of sodium and phosphate-containing precipitates was revealed through the EDS analysis. The results indicate that the increase in surface roughness due to conditioning is linked to a material's hydrophilicity leading to a rapid attachment of bacteria on the surfaces. Further investigations into the CFs can unfold crucial knowledge surrounding the plastic-microbe interaction that has implications for medical, industrial, and environmental research.
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Affiliation(s)
- Geetika Bhagwat
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Wayne O'Connor
- NSW Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, NSW, Australia
| | - Ian Grainge
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
| | - Thava Palanisami
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, NSW, Australia
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8
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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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9
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Pham DQ, Bryant SJ, Cheeseman S, Huang LZY, Bryant G, Dupont MF, Chapman J, Berndt CC, Vongsvivut JP, Crawford RJ, Truong VK, Ang ASM, Elbourne A. Micro- to nano-scale chemical and mechanical mapping of antimicrobial-resistant fungal biofilms. NANOSCALE 2020; 12:19888-19904. [PMID: 32985644 DOI: 10.1039/d0nr05617k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A fungal biofilm refers to the agglomeration of fungal cells surrounded by a polymeric extracellular matrix (ECM). The ECM is composed primarily of polysaccharides that facilitate strong surface adhesion, proliferation, and cellular protection from the surrounding environment. Biofilms represent the majority of known microbial communities, are ubiquitous, and are found on a multitude of natural and synthetic surfaces. The compositions, and in-turn nanomechanical properties, of fungal biofilms remain poorly understood, because these systems are complex, composed of anisotropic cellular and extracellular material, and importantly are species and environment dependent. Therefore, genomic variation, and/or mutations, as well as environmental and growth factors can change the composition of a fungal cell's biofilm. In this work, we probe the physico-mechanical and biochemical properties of two fungal species, Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans), as well as two antifungal resistant sub-species of C. neoformans, fluconazole-resistant C. neoformans (FlucRC. neoformans) and amphotericin B-resistant C. neoformans (AmBRC. neoformans). A new experimental methodology of characterization is proposed, employing a combination of atomic force microscopy (AFM), instrumented nanoindentation, and Synchrotron ATR-FTIR measurements. This allowed the nano-mechanical and chemical characterisation of each fungal biofilm.
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Affiliation(s)
- Duy Quang Pham
- Surface Engineering for Advanced Materials (SEAM), Department of Mechanical and Production Design Engineering, Swinburne University of Technology, Hawthorn, Australia.
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10
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Arzi RS, Sosnik A, Cohen N. A Microscopically Motivated Model for Particle Penetration into Swollen Biological Networks. Polymers (Basel) 2020; 12:polym12091912. [PMID: 32854259 PMCID: PMC7565132 DOI: 10.3390/polym12091912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Biological gels (bio-gels) are hydrated polymer networks that serve diverse biological functions, which often lead to intentional or unintentional exposure to particulate matter. In this work, we derive a microscopically motivated framework that enables the investigation of penetration mechanisms into bio-gels. We distinguish between two types of mechanisms: spontaneous (unforced) penetration and forced penetration. Using experimental data available in the literature, we exploit the proposed model to characterize and compare between the microstructures of respiratory, intestinal, and cervicovaginal mucus and two types of biofilms. Next, we investigate the forced penetration process of spherical and ellipsoidal particles into a locally quadrilateral network. The proposed framework can be used to improve and complement the analysis of experimental findings in vitro, ex vivo, and in vivo. Additionally, the insights from this work pave the way towards enhanced designs of nano-medicines and allow the assessment of risk factors related to the nano-pollutants exposure.
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Affiliation(s)
- Roni Sverdlov Arzi
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel;
- Mechanics of Soft Materials, Department of Materials Science and Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
| | - Alejandro Sosnik
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel;
- Correspondence: (A.S.); (N.C.)
| | - Noy Cohen
- Mechanics of Soft Materials, Department of Materials Science and Engineering, Technion—Israel Institute of Technology, Haifa 3200003, Israel
- Correspondence: (A.S.); (N.C.)
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11
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Gomes IB, Simões LC, Simões M. Influence of surface copper content on Stenotrophomonas maltophilia biofilm control using chlorine and mechanical stress. BIOFOULING 2020; 36:1-13. [PMID: 31997661 DOI: 10.1080/08927014.2019.1708334] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
This work aimed to evaluate the action of materials with different copper content (0, 57, 96 and 100%) on biofilm formation and control by chlorination and mechanical stress. Stenotrophomonas maltophilia isolated from drinking water was used as a model microorganism and biofilms were developed in a rotating cylinder reactor using realism-based shear stress conditions. Biofilms were characterized phenotypically and exposed to three control strategies: 10 mg l-1 of free chlorine for 10 min, an increased shear stress (a fluid velocity of 1.5 m s-1 for 30s), and a combination of both treatments. These shock treatments were not effective in biofilm control. The benefits from the use of copper surfaces was found essentially in reducing the numbers of non-damaged cells. Copper materials demonstrated better performance in biofilm prevention than chlorine. In general, copper alloys may have a positive public health impact by reducing the number of non-damaged cells in the water delivered after chlorine exposure.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - L C Simões
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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12
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Halvey AK, Macdonald B, Dhyani A, Tuteja A. Design of surfaces for controlling hard and soft fouling. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180266. [PMID: 30967072 PMCID: PMC6335287 DOI: 10.1098/rsta.2018.0266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/12/2018] [Indexed: 05/29/2023]
Abstract
In this review, we present a framework to guide the design of surfaces which are resistant to solid fouling, based on the modulus and length scale of the fouling material. Solid fouling is defined as the undesired attachment of solid contaminants including ice, clathrates, waxes, inorganic scale, polymers, proteins, dust and biological materials. We first provide an overview of the surface design approaches typically applied across the scope of solid fouling and explain how these disparate research efforts can be united to an extent under a single framework. We discuss how the elastic modulus and the operating length scale of a foulant determine its ability or inability to elastically deform surfaces. When surface deformation occurs, minimization of the substrate elastic modulus is critical for the facile de-bonding of a solid contaminant. Foulants with low modulus or small deposition sizes cannot deform an elastic bulk material and instead de-bond more readily from surfaces with chemistries that minimize their interfacial free energy or induce a particular repellant interaction with the foulant. Overall, we review reported surface design strategies for the reduction in solid fouling, and provide perspective regarding how our framework, together with the modulus and length scale of a foulant, can guide future antifouling surface designs. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology'.
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Affiliation(s)
- Alex Kate Halvey
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- BioInterfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brian Macdonald
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- BioInterfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Abhishek Dhyani
- BioInterfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anish Tuteja
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- BioInterfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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13
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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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14
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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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15
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Perrin A, Herbelin P, Jorand FPA, Skali-Lami S, Mathieu L. Design of a rotating disk reactor to assess the colonization of biofilms by free-living amoebae under high shear rates. BIOFOULING 2018; 34:368-377. [PMID: 29745778 DOI: 10.1080/08927014.2018.1444756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 02/20/2018] [Indexed: 06/08/2023]
Abstract
The present study was aimed at designing and optimizing a rotating disk reactor simulating high hydrodynamic shear rates (γ), which are representative of cooling circuits. The characteristics of the hydrodynamic conditions in the reactor and the complex approach used to engineer it are described. A 60 l tank was filled with freshwater containing free-living amoebae (FLA) and bacteria. Adhesion of the bacteria and formation of a biofilm on the stainless steel coupons were observed. FLA were able to establish in these biofilms under γ as high as 85,000 s-1. Several physical mechanisms (convection, diffusion, sedimentation) could explain the accumulation of amoeboid cells on surfaces, but further research is required to fully understand and model the fine mechanisms governing such transport under γ similar to those encountered in the industrial environment. This technological advance may enable research into these topics.
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Affiliation(s)
- A Perrin
- a Université de Lorraine, CNRS, LCPME , F-54000 Nancy , France
- b EDF Recherche et Développement, Laboratoire National d'Hydraulique et Environnement , F-78401 Chatou , France
| | - P Herbelin
- b EDF Recherche et Développement, Laboratoire National d'Hydraulique et Environnement , F-78401 Chatou , France
| | - F P A Jorand
- a Université de Lorraine, CNRS, LCPME , F-54000 Nancy , France
| | - S Skali-Lami
- c Université de Lorraine, CNRS, LEMTA , F-54000 Nancy , France
| | - L Mathieu
- a Université de Lorraine, CNRS, LCPME , F-54000 Nancy , France
- d EPHE, PSL Research University, LCPME , F-54000 Nancy , France
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16
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Allen A, Habimana O, Casey E. The effects of extrinsic factors on the structural and mechanical properties of Pseudomonas fluorescens biofilms: A combined study of nutrient concentrations and shear conditions. Colloids Surf B Biointerfaces 2018; 165:127-134. [PMID: 29471219 DOI: 10.1016/j.colsurfb.2018.02.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 01/17/2018] [Accepted: 02/14/2018] [Indexed: 12/16/2022]
Abstract
The growth of biofilms on surfaces is a complicated process influenced by several environmental factors such as nutrient availability and fluid shear. In this study, combinations of growth conditions were selected for the study of Pseudomonas fluorescens biofilms including as cultivation time (24- or 48 h), nutrient levels (1:1 or 1:10 King B medium), and shear conditions (75 RPM shaking, 0.4 mL min -1 or 0.7 mL min -1). The use of Confocal Laser Scanning Microscopy (CLSM) determined biofilm structure, while liquid-phase Atomic Force Microscopy (AFM) techniques resolved the mechanical properties of biofilms. Under semi-static conditions, high nutrient environments led to more abundant biofilms with three times higher EPS content compared to biofilms grown under low nutrient conditions. AFM results revealed that biofilms formed under these conditions were less stiff, as shown by their Young's modulus values of 2.35 ± 0.08 kPa, compared to 4.98 ± 0.02 kPa for that of biofilms formed under low nutrient conditions. Under dynamic conditions, however, biofilms exposed to low nutrient conditions and high shear rates led to more developed biofilms compared to other tested dynamic conditions. These biofilms were also found to be significantly more adhesive compared to their counterparts grown at higher nutrient conditions.
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Affiliation(s)
- Ashley Allen
- School of Engineering, The University of Edinburgh, Edinburgh, UK
| | - Olivier Habimana
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Eoin Casey
- School of Chemical and Bioprocess Engineering, University College Dublin (UCD), Belfield, Dublin 4, Ireland.
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17
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Francius G, El Zein R, Mathieu L, Gosselin F, Maul A, Block JC. Nano-exploration of organic conditioning film formed on polymeric surfaces exposed to drinking water. WATER RESEARCH 2017; 109:155-163. [PMID: 27883920 DOI: 10.1016/j.watres.2016.11.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/08/2016] [Accepted: 11/11/2016] [Indexed: 05/16/2023]
Abstract
Adsorption of organic macromolecules onto surfaces in contact with waters forms a so-called conditioning film and induces modifications of the surface properties. Here, we characterized conditioning films formed onto two hydrophobic materials (used as pipe liner) and immersed for 24 h in tap water. Using combination of atomic force microscopy (AFM), and chemical force microscopy (CFM), we detected some changes in roughness and hydrophilic/hydrophobic balance of the surface of the tested coupons, and also the deposition of numerous organic polymers (few millions/cm2) randomly distributed on the surface. The maximum molecular extension of these organic polymers was in the range of 250-1250 nm according to the tested materials. Systematic analysis of the force curves with the theoretical models (WLC and FJC) allowed determining the proportion of rupture events related to the unfolding of both polysaccharide and polypeptide segments, which represented 75-80% and 20-25% of the analyzed curves, respectively. The number of autochthonous drinking water bacteria, which attached to the material within the same period of time was 10000-folds lower than the detected number of polymers attached to the surface. Even in drinking water systems with relatively low organic matter (dissolved organic carbon < 1.1 mg/L), the potential of formation of a conditioning biofilm is important.
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Affiliation(s)
- Grégory Francius
- CNRS - Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Villers-lès-Nancy, F-54600, France.
| | - Racha El Zein
- CNRS - Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Villers-lès-Nancy, F-54600, France
| | - Laurence Mathieu
- EPHE, PSL Research University, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Vandoeuvre-lès-Nancy, F-54500, France
| | - Florence Gosselin
- CNRS - Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Villers-lès-Nancy, F-54600, France
| | - Armand Maul
- Université de Lorraine - CNRS, Laboratoire interdisciplinaire des environnements continentaux, LIEC, UMR 7360, Metz, F-57070, France
| | - Jean-Claude Block
- CNRS - Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Villers-lès-Nancy, F-54600, France
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18
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Microrheology of growing Escherichia coli biofilms investigated by using magnetic force modulation atomic force microscopy. Biointerphases 2016; 11:041005. [PMID: 27907987 DOI: 10.1116/1.4968809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Microrheology of growing biofilms provides insightful information about its structural evolution and properties. In this study, the authors have investigated the microrheology of Escherichia coli (strain HCB1) biofilms at different indentation depth (δ) by using magnetic force modulation atomic force microscopy as a function of disturbing frequency (f). As δ increases, the dynamic stiffness (ks) for the biofilms in the early stage significantly increases. However, it levels off when the biofilms are matured. The facts indicate that the biofilms change from inhomogeneous to homogeneous in structure. Moreover, ks is scaled to f, which coincides with the rheology of soft glasses. The exponent increases with the incubation time, indicating the fluidization of biofilms. In contrast, the upper layer of the matured biofilms is solidlike in that the storage modulus is always larger than the loss modulus, and its viscoelasticity is slightly influenced by the shear stress.
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19
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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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20
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Chew SC, Kundukad B, Teh WK, Doyle P, Yang L, Rice SA, Kjelleberg S. Mechanical signatures of microbial biofilms in micropillar-embedded growth chambers. SOFT MATTER 2016; 12:5224-5232. [PMID: 27191395 DOI: 10.1039/c5sm02755a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Biofilms are surface-attached communities of microorganisms embedded in an extracellular matrix and are essential for the cycling of organic matter in natural and engineered environments. They are also the leading cause of many infections, for example, those associated with chronic wounds and implanted medical devices. The extracellular matrix is a key biofilm component that determines its architecture and defines its physical properties. Herein, we used growth chambers embedded with micropillars to study the net mechanical forces (differential pressure) exerted during biofilm formation in situ. Pressure from the biofilm is transferred to the micropillars via the extracellular matrix, and reduction of major matrix components decreases the magnitude of micropillar deflections. The spatial arrangement of micropillar deflections caused by pressure differences in the different biofilm strains may potentially be used as mechanical signatures for biofilm characterization. Hence, we submit that micropillar-embedded growth chambers provide insights into the mechanical properties and dynamics of the biofilm and its matrix.
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Affiliation(s)
- S C Chew
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore.
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21
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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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22
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Daniels SL, Pressman JG, Wahman DG. AFM structural characterization of drinking water biofilm under physiological conditions. RSC Adv 2016. [DOI: 10.1039/c5ra20606e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Insights into the complex morphology of multi-species drinking water biofilm using atomic force microscopy (AFM).
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Affiliation(s)
- Stephanie L. Daniels
- Oak Ridge Institute for Science and Education
- Oak Ridge
- USA
- Water Supply and Water Resource Division
- National Risk Management Research Laboratory
| | - Jonathan G. Pressman
- Water Supply and Water Resource Division
- National Risk Management Research Laboratory
- U.S. Environmental Protection Agency
- Cincinnati
- USA
| | - David G. Wahman
- Water Supply and Water Resource Division
- National Risk Management Research Laboratory
- U.S. Environmental Protection Agency
- Cincinnati
- USA
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23
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Mechanics of Bacterial Cells and Initial Surface Colonisation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:245-60. [DOI: 10.1007/978-3-319-32189-9_15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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24
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Ditsche P, Wainwright DK, Summers AP. Attachment to challenging substrates--fouling, roughness and limits of adhesion in the northern clingfish (Gobiesox maeandricus). ACTA ACUST UNITED AC 2015; 217:2548-54. [PMID: 25031458 DOI: 10.1242/jeb.100149] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Northern clingfish use a ventral suction disc to stick to rough substrates in the intertidal zone. Bacteria, algae and invertebrates grow on these surfaces (fouling) and change the surface properties of the primary substrate, and therefore the attachment conditions for benthic organisms. In this study, we investigate the influence of fouling and surface roughness on the adhesive strength of northern clingfish, Gobiesox maeandricus. We measured clingfish tenacity on unfouled and fouled substrates over four surface roughnesses. We exposed surfaces for 6 weeks in the Pacific Ocean, until they were covered with periphyton. Clingfish tenacity is equivalent on both fouled and unfouled smooth substrates; however, tenacity on fouled rough surfaces is less compared with tenacity on unfouled ones. We hypothesize that parts of biofilm may act as a lubricant and decrease friction of the disc margin, thereby making disc margins slip inwards and fail at lower tenacities. Nevertheless, even on fouled surfaces the adhesive forces are approximately 150 times the body weight of the fish. To identify the upper threshold of surface roughness the fish can cling to, we tested seven unfouled substrates of increasing surface roughness. The threshold roughness at which northern clingfish failed increased with specimen size. We hypothesize that because of the elastic properties of the disc margin, a larger disc can adapt to larger surface irregularities. The largest specimens (length 10-12 cm) were able to cling to surfaces with 2-4 mm grain size. The fish can attach to surfaces with roughness between 2 and 9% of the suction disc width.
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Affiliation(s)
- Petra Ditsche
- University of Washington, Friday Harbor Laboratories, WA 98250, USA Department of Functional Morphology and Biomechanics, Zoological Institute of the University of Kiel, 24098 Kiel, Germany
| | - Dylan K Wainwright
- University of Washington, Friday Harbor Laboratories, WA 98250, USA Harvard University, Cambridge, MA 02138, USA
| | - Adam P Summers
- University of Washington, Friday Harbor Laboratories, WA 98250, USA
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25
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Zhu Y, Zhang Y, Ren HQ, Geng JJ, Xu K, Huang H, Ding LL. Physicochemical characteristics and microbial community evolution of biofilms during the start-up period in a moving bed biofilm reactor. BIORESOURCE TECHNOLOGY 2015; 180:345-51. [PMID: 25636169 DOI: 10.1016/j.biortech.2015.01.006] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/01/2015] [Accepted: 01/03/2015] [Indexed: 05/06/2023]
Abstract
This study aimed to investigate biofilm properties evolution coupled with different ages during the start-up period in a moving bed biofilm reactor system. Physicochemical characteristics including adhesion force, extracellular polymeric substances (EPS), morphology as well as volatile solid and microbial community were studied. Results showed that the formation and development of biofilms exhibited four stages, including (I) initial attachment and young biofilm formation, (II) biofilms accumulation, (III) biofilm sloughing and updating, and (IV) biofilm maturation. During the whole start-up period, adhesion force was positively and significantly correlated with the contents of EPS, especially the content of polysaccharide. In addition, increased adhesion force and EPS were beneficial for biofilm retention. Gram-negative bacteria mainly including Sphaerotilus, Zoogloea and Haliscomenobacter were predominant in the initial stage. Actinobacteria was beneficial to resist sloughing. Furthermore, filamentous bacteria were dominant in maturation biofilm.
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Affiliation(s)
- Yan Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Yan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
| | - Jin-Ju Geng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Ke Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hui Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Li-Li Ding
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China.
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26
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Safari A, Tukovic Z, Walter M, Casey E, Ivankovic A. Mechanical properties of a mature biofilm from a wastewater system: from microscale to macroscale level. BIOFOULING 2015; 31:651-64. [PMID: 26371590 DOI: 10.1080/08927014.2015.1075981] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A fundamental understanding of biofilm mechanical stability is critical in order to describe detachment and develop biofouling control strategies. It is thus important to characterise the elastic deformation and flow behaviour of the biofilm under different modes of applied force. In this study, the mechanical properties of a mature wastewater biofilm were investigated with methods including macroscale compression and microscale indentation using atomic force microscopy (AFM). The mature biofilm was found to be mechanically isotropic at the macroscale level as its mechanical properties did not depend on the scales and modes of loading. However, the biofilm showed a tendency for mechanical inhomogeneity at the microscale level as indentation progressed deeper into the matrix. Moreover, it was observed that the adhesion force had a significant influence on the elastic properties of the biofilm at the surface, subjected to microscale tensile loading. These results are expected to inform a damage-based model for biofilm detachment.
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Affiliation(s)
- Ashkan Safari
- a School of Electrical, Electronic and Mechanical Engineering , University College Dublin (UCD) , Dublin , Ireland
| | - Zeljko Tukovic
- b Faculty of Mechanical Engineering and Naval Architecture , University of Zagreb , Zagreb , Croatia
| | - Maik Walter
- c School of Chemical and Bioprocess Engineering , University College Dublin (UCD) , Dublin , Ireland
| | - Eoin Casey
- c School of Chemical and Bioprocess Engineering , University College Dublin (UCD) , Dublin , Ireland
| | - Alojz Ivankovic
- a School of Electrical, Electronic and Mechanical Engineering , University College Dublin (UCD) , Dublin , Ireland
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Gomes IB, Simões M, Simões LC. An overview on the reactors to study drinking water biofilms. WATER RESEARCH 2014; 62:63-87. [PMID: 24937357 DOI: 10.1016/j.watres.2014.05.039] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
The development of biofilms in drinking water distribution systems (DWDS) can cause pipe degradation, changes in the water organoleptic properties but the main problem is related to the public health. Biofilms are the main responsible for the microbial presence in drinking water (DW) and can be reservoirs for pathogens. Therefore, the understanding of the mechanisms underlying biofilm formation and behavior is of utmost importance in order to create effective control strategies. As the study of biofilms in real DWDS is difficult, several devices have been developed. These devices allow biofilm formation under controlled conditions of physical (flow velocity, shear stress, temperature, type of pipe material, etc), chemical (type and amount of nutrients, type of disinfectant and residuals, organic and inorganic particles, ions, etc) and biological (composition of microbial community - type of microorganism and characteristics) parameters, ensuring that the operational conditions are similar as possible to the DWDS conditions in order to achieve results that can be applied to the real scenarios. The devices used in DW biofilm studies can be divided essentially in two groups, those usually applied in situ and the bench top laboratorial reactors. The selection of a device should be obviously in accordance with the aim of the study and its advantages and limitations should be evaluated to obtain reproducible results that can be transposed into the reality of the DWDS. The aim of this review is to provide an overview on the main reactors used in DW biofilm studies, describing their characteristics and applications, taking into account their main advantages and limitations.
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Affiliation(s)
- I B Gomes
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - M Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
| | - L C Simões
- LEPABE, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal; CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Mathieu L, Bertrand I, Abe Y, Angel E, Block JC, Skali-Lami S, Francius G. Drinking water biofilm cohesiveness changes under chlorination or hydrodynamic stress. WATER RESEARCH 2014; 55:175-184. [PMID: 24607313 DOI: 10.1016/j.watres.2014.01.054] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/28/2013] [Accepted: 01/25/2014] [Indexed: 06/03/2023]
Abstract
Attempts at removal of drinking water biofilms rely on various preventive and curative strategies such as nutrient reduction in drinking water, disinfection or water flushing, which have demonstrated limited efficiency. The main reason for these failures is the cohesiveness of the biofilm driven by the physico-chemical properties of its exopolymeric matrix (EPS). Effective cleaning procedures should break up the matrix and/or change the elastic properties of bacterial biofilms. The aim of this study was to evaluate the change in the cohesive strength of two-month-old drinking water biofilms under increasing hydrodynamic shear stress τw (from ∼0.2 to ∼10 Pa) and shock chlorination (applied concentration at T0: 10 mg Cl2/L; 60 min contact time). Biofilm erosion (cell loss per unit surface area) and cohesiveness (changes in the detachment shear stress and cluster volumes measured by atomic force microscopy (AFM)) were studied. When rapidly increasing the hydrodynamic constraint, biofilm removal was found to be dependent on a dual process of erosion and coalescence of the biofilm clusters. Indeed, 56% of the biofilm cells were removed with, concomitantly, a decrease in the number of the 50-300 μm(3) clusters and an increase in the number of the smaller (i.e., <50 μm(3)) and larger (i.e., >600 μm(3)) ones. Moreover, AFM evidenced the strengthening of the biofilm structure along with the doubling of the number of contact points, NC, per cluster volume unit following the hydrodynamic disturbance. This suggests that the compactness of the biofilm exopolymers increases with hydrodynamic stress. Shock chlorination removed cells (-75%) from the biofilm while reducing the volume of biofilm clusters. Oxidation stress resulted in a decrease in the cohesive strength profile of the remaining drinking water biofilms linked to a reduction in the number of contact points within the biofilm network structure in particular for the largest biofilm cluster volumes (>200 μm(3)). Changes in the cohesive strength of drinking water biofilms subsequent to cleaning/disinfection operations call into question the effectiveness of cleaning-in-place procedures. The combined alternating use of oxidation and shear stress sequences needs to be investigated as it could be an important adjunct to improving biofilm removal/reduction procedures.
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Affiliation(s)
- L Mathieu
- Ecole Pratique des Hautes Etudes (EPHE), LCPME, UMR 7564 CNRS - Université de Lorraine, Nancy, France.
| | - I Bertrand
- CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Nancy, France
| | - Y Abe
- CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Nancy, France
| | - E Angel
- Ecole Pratique des Hautes Etudes (EPHE), LCPME, UMR 7564 CNRS - Université de Lorraine, Nancy, France
| | - J C Block
- CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Nancy, France
| | - S Skali-Lami
- CNRS and Université de Lorraine, Laboratoire d'Energétique et de Mécanique Théorique et Appliquée (LEMTA), UMR 7563, Nancy, France
| | - G Francius
- CNRS and Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Nancy, France
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Liu R, Zhu J, Yu Z, Joshi D, Zhang H, Lin W, Yang M. Molecular analysis of long-term biofilm formation on PVC and cast iron surfaces in drinking water distribution system. J Environ Sci (China) 2014; 26:865-874. [PMID: 25079417 DOI: 10.1016/s1001-0742(13)60481-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 08/07/2013] [Accepted: 09/06/2013] [Indexed: 06/03/2023]
Abstract
To understand the impacts of different plumbing materials on long-term biofilm formation in water supply system, we analyzed microbial community compositions in the bulk water and biofilms on faucets with two different materials-polyvinyl chloride (PVC) and cast iron, which have been frequently used for more than10 years. Pyrosequencing was employed to describe both bacterial and eukaryotic microbial compositions. Bacterial communities in the bulk water and biofilm samples were significantly different from each other. Specific bacterial populations colonized on the surface of different materials. Hyphomicrobia and corrosion associated bacteria, such as Acidithiobacillus spp., Aquabacterium spp., Limnobacter thiooxidans, and Thiocapsa spp., were the most dominant bacteria identified in the PVC and cast iron biofilms, respectively, suggesting that bacterial colonization on the material surfaces was selective. Mycobacteria and Legionella spp. were common potential pathogenic bacteria occurred in the biofilm samples, but their abundance was different in the two biofilm bacterial communities. In contrast, the biofilm samples showed more similar eukaryotic communities than the bulk water. Notably, potential pathogenic fungi, i.e., Aspergillus spp. and Candida parapsilosis, occurred in similar abundance in both biofilms. These results indicated that microbial community, especially bacterial composition was remarkably affected by the different pipe materials (PVC and cast iron).
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Affiliation(s)
- Ruyin Liu
- College of Environmental and Resource Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Junge Zhu
- Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhisheng Yu
- College of Environmental and Resource Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - DevRaj Joshi
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Hongxun Zhang
- College of Environmental and Resource Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenfang Lin
- College of Environmental and Resource Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Yang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Safari A, Habimana O, Allen A, Casey E. The significance of calcium ions on Pseudomonas fluorescens biofilms - a structural and mechanical study. BIOFOULING 2014; 30:859-869. [PMID: 25115520 DOI: 10.1080/08927014.2014.938648] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of this study was to investigate the effects of calcium ions on the structural and mechanical properties of Pseudomonas fluorescens biofilms grown for 48 h. Advanced investigative techniques such as confocal laser scanning microscopy and atomic force spectroscopy were employed to characterize biofilm structure as well as biofilm mechanical properties following growth at different calcium concentrations. The presence of calcium during biofilm development led to higher surface coverage with distinct structural phenotypes in the form of a granular and heterogeneous surface, compared with the smoother and homogeneous biofilm surface in the absence of calcium. The presence of calcium also increased the adhesive nature of the biofilm, while reducing its elastic properties. These results suggest that calcium ions could have a functional role in biofilm development and have practical implications, for example, in analysis of biofouling in membrane-based water-treatment processes such as nanofiltration or reverse osmosis where elevated calcium concentrations may occur at the solid-liquid interface.
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Affiliation(s)
- Ashkan Safari
- a School of Chemical and Bioprocess Engineering , University College Dublin (UCD) , Belfield , Dublin , Ireland
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Ditsche P, Michels J, Kovalev A, Koop J, Gorb S. More than just slippery: the impact of biofilm on the attachment of non-sessile freshwater mayfly larvae. J R Soc Interface 2013; 11:20130989. [PMID: 24352675 DOI: 10.1098/rsif.2013.0989] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
While terrestrial insects can usually attach directly to a substrate, for aquatic insects the situation is more complicated owing to the presence of a biofilm on the primary substrates. This important fact has been neither the subject of investigation nor commonly taken into account in the interpretation of functional aspects of attachment in mobile freshwater animals. In this study, we investigate the impact of a biofilm on the attachment of living mayfly larvae. We performed in vivo attachment experiments in a flow channel using different substrates with defined surface roughness. Additionally, we measured friction forces directly generated by dissected tarsal claws on the same substrates. On substrates with smooth or slightly rough surfaces, which have little or no surface irregularities large enough for the claws to grasp, the presence of a biofilm significantly increases the friction force of claws. Consequently, larvae can endure higher flow velocities on these smooth substrates. The opposite effect takes place on rough substrates, where the friction force of claws decreases in the presence of a biofilm. Consequently, a biofilm is a critical ecological structure for these larvae, and other aquatic organisms, not only as a food source but also as a factor influencing attachment ability.
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Affiliation(s)
- Petra Ditsche
- Department of Functional Morphology and Biomechanics, Zoological Institute, University of Kiel, , Am Botanischen Garten 9, 24118 Kiel, Germany
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Gosselin F, Madeira LM, Juhna T, Block JC. Drinking water and biofilm disinfection by Fenton-like reaction. WATER RESEARCH 2013; 47:5631-5638. [PMID: 23866142 DOI: 10.1016/j.watres.2013.06.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/17/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics.
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Affiliation(s)
- F Gosselin
- Université de Lorraine and CNRS, LCPME, UMR 7564, 405 rue de Vandoeuvre, 54600 Villers-lès-Nancy, France
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Francius G, Henry R, Duval JFL, Bruneau E, Merlin J, Fahs A, Leblond-Bourget N. Thermo-regulated adhesion of the Streptococcus thermophilus Δrgg0182 strain. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4847-4856. [PMID: 23530723 DOI: 10.1021/la4001895] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The physicochemical determinants governing the temperature-dependent adhesion of Streptococcus thermophilus to abiotic surfaces are identified under physiological condition for cells either lacking or not the Rgg0182 transcriptional regulator involved in their thermal adaptation. For that purpose, the wild type LMG18311 strain and Δrgg0182 mutant were imaged using highly resolved atomic force microscopy (AFM) at various cell growth temperatures (42 to 55 °C). The corresponding hydrophobic/hydrophilic balance of the cells was quantitatively addressed via the measurement by chemical force microcopy of their adhesion to a reference hydrophobic surface. Analysis of force-separation distance curves further allowed us to discriminate cell surfaces according to the presence or absence of biopolymers. These results were interpreted in relation to the measured adhesion of the Δrgg0182 mutant onto the hydrophobic wall of microwells in the temperature range from 46 to 52 °C. It is evidenced that the viscoelastic Δrgg0182 cell envelop behaves as a thermo-responsive film whose hydrophobicity increases with increasing temperature, thereby favoring cell attachment to hydrophobic surfaces. Regardless cell growth temperature, wild-type cells do not attach to hydrophobic surfaces and the presence of the Rgg0182 transcriptional regulator is associated with the synthesis of hydrophilic cell surface biopolymers. Throughout, the impact of electrostatics on bioadhesion is ruled out upon examination of electrohydrodynamic cell properties at 50 °C.
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Affiliation(s)
- Grégory Francius
- Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME, UMR 7564, Villers-lès-Nancy F-54600, France.
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35
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Powell LC, Sowedan A, Khan S, Wright CJ, Hawkins K, Onsøyen E, Myrvold R, Hill KE, Thomas DW. The effect of alginate oligosaccharides on the mechanical properties of Gram-negative biofilms. BIOFOULING 2013; 29:413-21. [PMID: 23574333 DOI: 10.1080/08927014.2013.777954] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The influence of a novel, safe antibiofilm therapy on the mechanical properties of Pseudomonas aeruginosa and Acinetobacter baumannii biofilms in vitro was characterized. A multiscale approach employing atomic force microscopy (AFM) and rheometry was used to quantify the mechanical disruption of the biofilms by a therapeutic polymer based on a low-molecular weight alginate oligosaccharide (OligoG). AFM demonstrated structural alterations in the biofilms exposed to OligoG, with significantly lower Young's moduli than the untreated biofilms, (149 MPa vs 242 MPa; p < 0.05), a decreased resistance to hydrodynamic shear and an increased surface irregularity (Ra) in the untreated controls (35.2 nm ± 7.6 vs 12.1 nm ± 5.4; p < 0.05). Rheology demonstrated that increasing clinically relevant concentrations of OligoG (<10%) were associated with an increasing phase angle (δ) over a wide range of frequencies (0.1-10 Hz). These results highlight the utility of these techniques for the study of three-dimensional biofilms and for quantifying novel disruption therapies in vitro.
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Affiliation(s)
- Lydia C Powell
- Tissue Engineering and Reparative Dentistry, Wound Biology Group, School of Dentistry, Cardiff University, Cardiff, UK
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Abe Y, Skali-Lami S, Block JC, Francius G. Cohesiveness and hydrodynamic properties of young drinking water biofilms. WATER RESEARCH 2012; 46:1155-1166. [PMID: 22221338 DOI: 10.1016/j.watres.2011.12.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/30/2011] [Accepted: 12/06/2011] [Indexed: 05/31/2023]
Abstract
Drinking water biofilms are complex microbial systems mainly composed of clusters of different size and age. Atomic force microscopy (AFM) measurements were performed on 4, 8 and 12 weeks old biofilms in order to quantify the mechanical detachment shear stress of the clusters, to estimate the biofilm entanglement rate ξ. This AFM approach showed that the removal of the clusters occurred generally for mechanical shear stress of about 100 kPa only for clusters volumes greater than 200 μm3. This value appears 1000 times higher than hydrodynamic shear stress technically available meaning that the cleaning of pipe surfaces by water flushing remains always incomplete. To predict hydrodynamic detachment of biofilm clusters, a theoretical model has been developed regarding the averaging of elastic and viscous stresses in the cluster and by including the entanglement rate ξ. The results highlighted a slight increase of the detachment shear stress with age and also the dependence between the posting of clusters and their volume. Indeed, the experimental values of ξ allow predicting biofilm hydrodynamic detachment with same order of magnitude than was what reported in the literature. The apparent discrepancy between the mechanical and the hydrodynamic detachment is mainly due to the fact that AFM mechanical experiments are related to the clusters local properties whereas hydrodynamic measurements reflected the global properties of the whole biofilm.
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Affiliation(s)
- Yumiko Abe
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Nancy-Université, CNRS, 405 rue de Vandœuvre, 54600 Villers-lès-Nancy, France
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