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Ugolini GS, Wang M, Secchi E, Pioli R, Ackermann M, Stocker R. Microfluidic approaches in microbial ecology. LAB ON A CHIP 2024; 24:1394-1418. [PMID: 38344937 PMCID: PMC10898419 DOI: 10.1039/d3lc00784g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Microbial life is at the heart of many diverse environments and regulates most natural processes, from the functioning of animal organs to the cycling of global carbon. Yet, the study of microbial ecology is often limited by challenges in visualizing microbial processes and replicating the environmental conditions under which they unfold. Microfluidics operates at the characteristic scale at which microorganisms live and perform their functions, thus allowing for the observation and quantification of behaviors such as growth, motility, and responses to external cues, often with greater detail than classical techniques. By enabling a high degree of control in space and time of environmental conditions such as nutrient gradients, pH levels, and fluid flow patterns, microfluidics further provides the opportunity to study microbial processes in conditions that mimic the natural settings harboring microbial life. In this review, we describe how recent applications of microfluidic systems to microbial ecology have enriched our understanding of microbial life and microbial communities. We highlight discoveries enabled by microfluidic approaches ranging from single-cell behaviors to the functioning of multi-cellular communities, and we indicate potential future opportunities to use microfluidics to further advance our understanding of microbial processes and their implications.
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Affiliation(s)
- Giovanni Stefano Ugolini
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Miaoxiao Wang
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Roberto Pioli
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
| | - Martin Ackermann
- Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Department of Environmental Microbiology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
- Laboratory of Microbial Systems Ecology, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédéral de Lausanne (EPFL), Lausanne, Switzerland
| | - Roman Stocker
- Department of Civil, Environmental and Geomatic Engineering, Institute of Environmental Engineering, ETH Zurich, Laura-Hezner-Weg 7, 8093 Zurich, Switzerland.
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Heredia-Ponce Z, Secchi E, Toyofuku M, Marinova G, Savorana G, Eberl L. Genotoxic stress stimulates eDNA release via explosive cell lysis and thereby promotes streamer formation of Burkholderia cenocepacia H111 cultured in a microfluidic device. NPJ Biofilms Microbiomes 2023; 9:96. [PMID: 38071361 PMCID: PMC10710452 DOI: 10.1038/s41522-023-00464-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
DNA is a component of biofilms, but the triggers of DNA release during biofilm formation and how DNA contributes to biofilm development are poorly investigated. One key mechanism involved in DNA release is explosive cell lysis, which is a consequence of prophage induction. In this article, the role of explosive cell lysis in biofilm formation was investigated in the opportunistic human pathogen Burkholderia cenocepacia H111 (H111). Biofilm streamers, flow-suspended biofilm filaments, were used as a biofilm model in this study, as DNA is an essential component of their matrix. H111 contains three prophages on chromosome 1 of its genome, and the involvement of each prophage in causing explosive cell lysis of the host and subsequent DNA and membrane vesicle (MV) release, as well as their contribution to streamer formation, were studied in the presence and absence of genotoxic stress. The results show that two of the three prophages of H111 encode functional lytic prophages that can be induced by genotoxic stress and their activation causes DNA and MVs release by explosive cell lysis. Furthermore, it is shown that the released DNA enables the strain to develop biofilm streamers, and streamer formation can be enhanced by genotoxic stress. Overall, this study demonstrates the involvement of prophages in streamer formation and uncovers an often-overlooked problem with the use of antibiotics that trigger the bacterial SOS response for the treatment of bacterial infections.
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Affiliation(s)
- Zaira Heredia-Ponce
- Department of Plant and Microbial Biology, University of Zürich, 8008, Zürich, Switzerland
| | - Eleonora Secchi
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093, Zürich, Switzerland
| | - Masanori Toyofuku
- Faculty of Life and Environmental Sciences, Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan
| | - Gabriela Marinova
- Department of Plant and Microbial Biology, University of Zürich, 8008, Zürich, Switzerland
| | - Giovanni Savorana
- Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zürich, 8093, Zürich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zürich, 8008, Zürich, Switzerland.
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Parente R, Fumagalli MR, Di Claudio A, Cárdenas Rincón CL, Erreni M, Zanini D, Iapichino G, Protti A, Garlanda C, Rusconi R, Doni A. A Multilayered Imaging and Microfluidics Approach for Evaluating the Effect of Fibrinolysis in Staphylococcus aureus Biofilm Formation. Pathogens 2023; 12:1141. [PMID: 37764949 PMCID: PMC10534389 DOI: 10.3390/pathogens12091141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
The recognition of microbe and extracellular matrix (ECM) is a recurring theme in the humoral innate immune system. Fluid-phase molecules of innate immunity share regulatory roles in ECM. On the other hand, ECM elements have immunological functions. Innate immunity is evolutionary and functionally connected to hemostasis. Staphylococcus aureus (S. aureus) is a major cause of hospital-associated bloodstream infections and the most common cause of several life-threatening conditions such as endocarditis and sepsis through its ability to manipulate hemostasis. Biofilm-related infection and sepsis represent a medical need due to the lack of treatments and the high resistance to antibiotics. We designed a method combining imaging and microfluidics to dissect the role of elements of the ECM and hemostasis in triggering S. aureus biofilm by highlighting an essential role of fibrinogen (FG) in adhesion and formation. Furthermore, we ascertained an important role of the fluid-phase activation of fibrinolysis in inhibiting biofilm of S. aureus and facilitating an antibody-mediated response aimed at pathogen killing. The results define FG as an essential element of hemostasis in the S. aureus biofilm formation and a role of fibrinolysis in its inhibition, while promoting an antibody-mediated response. Understanding host molecular mechanisms influencing biofilm formation and degradation is instrumental for the development of new combined therapeutic approaches to prevent the risk of S. aureus biofilm-associated diseases.
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Affiliation(s)
- Raffaella Parente
- Multiscale ImmunoImaging Unit (mIIu), IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Maria Rita Fumagalli
- Multiscale ImmunoImaging Unit (mIIu), IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Alessia Di Claudio
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
| | - Cindy Lorena Cárdenas Rincón
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
| | - Marco Erreni
- Multiscale ImmunoImaging Unit (mIIu), IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
| | - Damiano Zanini
- Multiscale ImmunoImaging Unit (mIIu), IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Giacomo Iapichino
- Department of Anesthesia and Intensive Care Units, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Alessandro Protti
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
- Department of Anesthesia and Intensive Care Units, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Cecilia Garlanda
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Roberto Rusconi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Italy
- IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
| | - Andrea Doni
- Multiscale ImmunoImaging Unit (mIIu), IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089 Rozzano, Italy
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Cheah H, Bae S. Multichannel Microfluidic Platform for Temporal-Spatial Investigation of Niche Roles of Pseudomonas aeruginosa and Escherichia coli within a Dual-Species Biofilm. Appl Environ Microbiol 2023; 89:e0065123. [PMID: 37382537 PMCID: PMC10370331 DOI: 10.1128/aem.00651-23] [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: 04/19/2023] [Accepted: 06/12/2023] [Indexed: 06/30/2023] Open
Abstract
In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. In this study, a microfluidic device designed with multiple channels and a gradient generator was used for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. We compared the structural parameters of monospecies and dual-species biofilms containing Pseudomonas aeruginosa (expressing mCherry) and Escherichia coli (expressing green fluorescent protein [GFP]) to understand the interactions in the biofilm. The rate of biovolume increase of each species in monospecies biofilm (2.7 × 105 μm3) was higher than those in a dual-species biofilm (9.68 × 104 μm3); however, synergism was still observed in the dual-species biofilm due to overall increases in biovolume for both species. Synergism was also observed in a dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. The microfluidic chip was useful for monitoring the dual-species biofilm in the microenvironment, indicating that different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. Finally, we demonstrated that the nucleic acids can be extracted from the dual-species biofilm in situ after biofilm imaging analysis. In addition, gene expression supported that the activation and suppression of different quorum sensing genes resulted in the different phenotype seen in the biofilm. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously. IMPORTANCE In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. Here, we demonstrate that a microfluidic device with multiple channels and a gradient generator can be useful for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. Our study revealed synergism in the dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. Furthermore, different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously.
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Affiliation(s)
- Hee Cheah
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Sungwoo Bae
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
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Lee SH, Secchi E, Kang PK. Rapid formation of bioaggregates and morphology transition to biofilm streamers induced by pore-throat flows. Proc Natl Acad Sci U S A 2023; 120:e2204466120. [PMID: 36989304 PMCID: PMC10083537 DOI: 10.1073/pnas.2204466120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 02/28/2023] [Indexed: 03/30/2023] Open
Abstract
Bioaggregates are condensed porous materials comprising microbes, organic and inorganic matters, and water. They are commonly found in natural and engineered porous media and often cause clogging. Despite their importance, the formation mechanism of bioaggregates in porous media systems is largely unknown. Through microfluidic experiments and direct numerical simulations of fluid flow, we show that the rapid bioaggregation is driven by the interplay of the viscoelastic nature of biomass and hydrodynamic conditions at pore throats. At an early stage, unique flow structures around a pore throat promote the biomass attachment at the throat. Then, the attached biomass fluidizes when the shear stress at the partially clogged pore throat reaches a critical value. After the fluidization, the biomass is displaced and accumulated in the expansion region of throats forming bioaggregates. We further find that such criticality in shear stress triggers morphological changes in bioaggregates from rounded- to streamer-like shapes. This knowledge was used to control the clogging of throats by tuning the flow conditions: When the shear stress at the throat exceeded the critical value, clogging was prevented. The bioaggregation process did not depend on the detailed pore-throat geometry, as we reproduced the same dynamics in various pore-throat geometries. This study demonstrates that pore-throat structures, which are ubiquitous in porous media systems, induce bioaggregation and can lead to abrupt disruptions in flow.
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Affiliation(s)
- Sang Hyun Lee
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN55455
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, Zürich8093, Switzerland
| | - Peter K. Kang
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN55455
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN55455
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Ramos G, Toulouze C, Rima M, Liot O, Duru P, Davit Y. Ultraviolet control of bacterial biofilms in microfluidic chips. BIOMICROFLUIDICS 2023; 17:024107. [PMID: 37124629 PMCID: PMC10132849 DOI: 10.1063/5.0135722] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
Polydimethylsiloxane (PDMS) microfluidic systems have been instrumental in better understanding couplings between physical mechanisms and bacterial biofilm processes, such as hydrodynamic effects. However, precise control of the growth conditions, for example, the initial distribution of cells on the substrate or the boundary conditions in a flow system, has remained challenging. Furthermore, undesired bacterial colonization in crucial parts of the systems, in particular, in mixing zones or tubing, is an important factor that strongly limits the duration of the experiments and, therefore, impedes our ability to study the biophysics of biofilm evolving over long periods of time, as found in the environment, in engineering, or in medicine. Here, we develop a new approach that uses ultraviolet-C (UV-C) light-emitting diodes (LEDs) to confine bacterial development to specific zones of interest in the flow channels. The LEDs are integrated into a 3D printed light guide that is positioned upon the chip and used to irradiate germicidal UV-C directly through the PDMS. We first demonstrate that this system is successful in controlling undesired growth of Pseudomonas aeruginosa biofilm in inlet and outlet mixing zones during 48 h. We further illustrate how this can be used to define the initial distribution of bacteria to perturb already formed biofilms during an experiment and to control colonization for seven days-and possibly longer periods of time-therefore opening the way toward long-term biofilm experiments in microfluidic devices. Our approach is easily generalizable to existing devices at low cost and may, thus, become a standard in biofilm experiments in PDMS microfluidics.
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Affiliation(s)
- Gabriel Ramos
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Clara Toulouze
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Maya Rima
- Laboratoire de Génie Chimique (LGC), Université de Toulouse, CNRS, INPT, UPS, 31062 Toulouse, France
| | - Olivier Liot
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Paul Duru
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
| | - Yohan Davit
- Institut de Mécanique des Fluides (IMFT), CNRS and Université de Toulouse, 31400 Toulouse, France
- Author to whom correspondence should be addressed:
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Geisel S, Secchi E, Vermant J. Experimental challenges in determining the rheological properties of bacterial biofilms. Interface Focus 2022; 12:20220032. [PMID: 36330324 PMCID: PMC9560794 DOI: 10.1098/rsfs.2022.0032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 08/01/2023] Open
Abstract
Bacterial biofilms are communities living in a matrix consisting of self-produced, hydrated extracellular polymeric substances. Most microorganisms adopt the biofilm lifestyle since it protects by conferring resistance to antibiotics and physico-chemical stress factors. Consequently, mechanical removal is often necessary but rendered difficult by the biofilm's complex, viscoelastic response, and adhesive properties. Overall, the mechanical behaviour of biofilms also plays a role in the spreading, dispersal and subsequent colonization of new surfaces. Therefore, the characterization of the mechanical properties of biofilms plays a crucial role in controlling and combating biofilms in industrial and medical environments. We performed in situ shear rheological measurements of Bacillus subtilis biofilms grown between the plates of a rotational rheometer under well-controlled conditions relevant to many biofilm habitats. We investigated how the mechanical history preceding rheological measurements influenced biofilm mechanics and compared these results to the techniques commonly used in the literature. We also compare our results to measurements using interfacial rheology on bacterial pellicles formed at the air-water interface. This work aims to help understand how different growth and measurement conditions contribute to the large variability of mechanical properties reported in the literature and provide a new tool for the rigorous characterization of matrix components and biofilms.
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Affiliation(s)
- Steffen Geisel
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
| | - Eleonora Secchi
- Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich, Switzerland
| | - Jan Vermant
- Laboratory for Soft Materials, Department of Materials, ETH Zurich, Zurich, Switzerland
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