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Ealla KKR, Kumari N, Chintalapani S, Uppu S, Sahu V, Veeraraghavan VP, Ramani P, Govindool SR. Interplay between dental caries pathogens, periodontal pathogens, and sugar molecules: approaches for prevention and treatment. Arch Microbiol 2024; 206:127. [PMID: 38416201 DOI: 10.1007/s00203-024-03856-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/13/2024] [Accepted: 01/20/2024] [Indexed: 02/29/2024]
Abstract
Globally, oral diseases affect nearly 3.5 billion people, accounting for 4.6% of the healthcare expenditure. Common oral diseases include dental caries and periodontal disease, associated with biofilms formed by cariogenic pathogens. Epidemiological studies associate carbohydrates with these diseases due to the sugars metabolized by cariogenic pathogens. This review focuses on dental caries and periodontal pathogens, quorum sensing, lectin-carbohydrate interactions, and various sugar molecules. Cariogenic sugars significantly influence biofilms by enhancing pathogen adhesion, viability, and gene expressions associated with biofilm formation. Moreover, lectin-carbohydrate interactions contribute to biofilm stability. Disrupting these interactions is a potential strategy for oral disease prevention. The use of nanoparticles, such as quantum dots, provides novel insights into lectin-sugar interactions and the development of inhibitors. Additionally, nanomaterials like calcium phosphate nanoparticles neutralize acids and inhibit microbial growth. This overview emphasizes understanding the relationships between oral diseases, microbial communities, and sugars to devise preventive and therapeutic strategies against oral diseases.
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Affiliation(s)
- Kranti Kiran Reddy Ealla
- Oral and Maxillofacial Pathology, Malla Reddy Institute of Dental Sciences, Hyderabad, Telangana, India.
- Oral and Maxillofacial Pathology, Saveetha Dental College & Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India.
| | - Neema Kumari
- Department of Microbiology, Malla Reddy Institute of Medical Sciences, Hyderabad, Telangana, India.
| | - Srikanth Chintalapani
- Department of Periodontology, Malla Reddy Institute of Dental Sciences, Hyderabad, Telangana, India
| | - Supriya Uppu
- Oral and Maxillofacial Pathology, Malla Reddy Institute of Dental Sciences, Hyderabad, Telangana, India
| | - Vikas Sahu
- Oral and Maxillofacial Pathology, Malla Reddy Institute of Dental Sciences, Hyderabad, Telangana, India
| | - Vishnu Priya Veeraraghavan
- Centre of Molecular Medicine and Diagnostics (COMManD), Saveetha Dental College & Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Pratibha Ramani
- Oral and Maxillofacial Pathology, Saveetha Dental College & Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
| | - Sharaschandra Reddy Govindool
- Department of Periodontics and Endodontics, School of Dental Medicine, University at Buffalo, 240D Squire Hall, Buffalo, NY, 14214, USA
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Del Rey YC, Schramm A, L. Meyer R, Lund MB, Schlafer S. Combined pH ratiometry and fluorescence lectin-binding analysis (pH-FLBA) for microscopy-based analyses of biofilm pH and matrix carbohydrates. Appl Environ Microbiol 2024; 90:e0200723. [PMID: 38265212 PMCID: PMC10880593 DOI: 10.1128/aem.02007-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/08/2023] [Indexed: 01/25/2024] Open
Abstract
Bacterial biofilms have a complex and heterogeneous three-dimensional architecture that is characterized by chemically and structurally distinct microenvironments. Confocal microscopy-based pH ratiometry and fluorescence lectin-binding analysis (FLBA) are well-established methods to characterize pH developments and the carbohydrate matrix architecture of biofilms at the microscale. Here, we developed a combined analysis, pH-FLBA, to concomitantly map biofilm pH and the distribution of matrix carbohydrates in bacterial biofilms while preserving the biofilm microarchitecture. As a proof of principle, the relationship between pH and the presence of galactose- and fucose-containing matrix components was investigated in dental biofilms grown with and without sucrose. The pH response to a sucrose challenge was monitored in different areas at the biofilm base using the ratiometric pH-sensitive dye C-SNARF-4. Thereafter, the fucose- and galactose-specific fluorescently labeled lectins Aleuria aurantia lectin (AAL) and Morus nigra agglutinin G (MNA-G) were used to visualize carbohydrate matrix components in the same biofilm areas and their immediate surroundings. Sucrose during growth significantly decreased biofilm pH (P < 0.05) and increased the amounts of both MNA-G- and AAL-targeted matrix carbohydrates (P < 0.05). Moreover, it modulated the biofilm composition towards a less diverse community dominated by streptococci, as determined by 16S rRNA gene sequencing. Altogether, these results suggest that the production of galactose- and fucose-containing matrix carbohydrates is related to streptococcal metabolism and, thereby, pH profiles in dental biofilms. In conclusion, pH-FLBA using lectins with different carbohydrate specificities is a useful method to investigate the association between biofilm pH and the complex carbohydrate architecture of bacterial biofilms.IMPORTANCEBiofilm pH is a key regulating factor in several biological and biochemical processes in environmental, industrial, and medical biofilms. At the microscale, microbial biofilms are characterized by steep pH gradients and an extracellular matrix rich in carbohydrate components with diffusion-modifying properties that contribute to bacterial acid-base metabolism. Here, we propose a combined analysis of pH ratiometry and fluorescence lectin-binding analysis, pH-FLBA, to concomitantly investigate the matrix architecture and pH developments in microbial biofilms, using complex saliva-derived biofilms as an example. Spatiotemporal changes in biofilm pH are monitored non-invasively over time by pH ratiometry, while FLBA with lectins of different carbohydrate specificities allows mapping the distribution of multiple relevant matrix components in the same biofilm areas. As the biofilm structure is preserved, pH-FLBA can be used to investigate the in situ relationship between the biofilm matrix architecture and biofilm pH in complex multispecies biofilms.
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Affiliation(s)
- Yumi C. Del Rey
- Section for Oral Ecology, Cariology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Rikke L. Meyer
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark
| | - Marie Braad Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Sebastian Schlafer
- Section for Oral Ecology, Cariology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
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Kristensen MF, Lund MB, Schramm A, Lau EF, Schlafer S. Determinants of Microscale pH in In Situ-Grown Dental Biofilms. J Dent Res 2023; 102:1348-1355. [PMID: 37697830 DOI: 10.1177/00220345231190563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023] Open
Abstract
Dental biofilm pH is the most important determinant of virulence for the development of caries lesions. Confocal microscopy-based pH ratiometry allows monitoring biofilm pH with high spatial resolution. Experiments performed on simplified biofilm models under static conditions identified steep pH gradients as well as localized acidogenic foci that promote enamel demineralization. The present work used pH ratiometry to perform a comprehensive analysis of the effect of whole saliva flow on the microscale pH in complex, in situ-grown 48-h and 96-h biofilms (n = 54) from 9 healthy participants. pH was monitored in 12 areas at the biofilm bottom and top, and saliva flow with film thicknesses corresponding to those in the oral cavity was provided by an additively manufactured microfluidic flow cell. Biofilm pH was correlated to the bacterial composition, as determined by 16S rRNA gene sequencing. Biofilm acidogenicity varied considerably between participants and individual biofilms but also between different areas inside one biofilm, with pH gradients of up to 2 units. pH drops were more pronounced in 96-h than in 48-h biofilms (P = 0.0121) and virtually unaffected by unstimulated saliva flow (0.8 mm/min). Stimulated flow (8 mm/min) raised average biofilm pH to near-neutral values but it did not equilibrate vertical and horizontal pH gradients in the biofilms. pH was significantly lower at the biofilm base than at the top (P < 0.0001) and lower downstream than upstream (P = 0.0046), due to an accumulation of acids along the flow path. pH drops were positively correlated with biofilm thickness and negatively with the thickness of the saliva film covering the biofilm. Bacterial community composition was significantly different between biofilms with strong and weak pH responses but not their species richness. The present experimental study demonstrates that stimulated saliva flow, saliva film thickness, biofilm age, biofilm thickness, and bacterial composition are important modulators of microscale pH in dental biofilms.
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Affiliation(s)
- M F Kristensen
- Section for Oral Ecology, Cariology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - M B Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - A Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - E Frandsen Lau
- Section for Oral Ecology, Cariology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - S Schlafer
- Section for Oral Ecology, Cariology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
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Dexamethasone-loaded zeolitic imidazolate frameworks nanocomposite hydrogel with antibacterial and anti-inflammatory effects for periodontitis treatment. Mater Today Bio 2022; 16:100360. [PMID: 35937574 PMCID: PMC9352959 DOI: 10.1016/j.mtbio.2022.100360] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/22/2022] Open
Abstract
Periodontitis is a bacterial-induced, chronic inflammatory disease characterized by progressive destruction of tooth-supporting structures. Pathogenic bacteria residing in deep periodontal pockets after traditional manual debridement can still lead to local inflammatory microenvironment, which remains a challenging problem and an urgent need for better therapeutic strategies. Here, we integrated the advantages of metal-organic frameworks (MOFs) and hydrogels to prepare an injectable nanocomposite hydrogel by incorporating dexamethasone-loaded zeolitic imidazolate frameworks-8 (DZIF) nanoparticles into the photocrosslinking matrix of methacrylic polyphosphoester (PPEMA) and methacrylic gelatin (GelMA). The injectable hydrogel could be easily injected into deep periodontal pockets, achieving high local concentrations without leading to antibiotic resistance. The nanocomposite hydrogel had high antibacterial activity and constructs with stable microenvironments maintain cell viability, proliferation, spreading, as well as osteogenesis, and down-regulated inflammatory genes expression in vitro. When evaluated on an experimental periodontitis rat model, micro-computed tomography and histological analyses showed that the nanocomposite hydrogel effectively reduced periodontal inflammation and attenuated inflammation-induced bone loss in a rat model of periodontitis. These findings suggest that the nanocomposite hydrogel might be a promising therapeutic candidate for treating periodontal disease.
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Schlafer S, Bornmann T, Paris S, Göstemeyer G. The impact of glass ionomer cement and composite resin on microscale pH in cariogenic biofilms and demineralization of dental tissues. Dent Mater 2021; 37:1576-1583. [PMID: 34419256 DOI: 10.1016/j.dental.2021.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Secondary caries is among the most frequent reasons for the failure of dental restorations. Glass ionomer cement (GIC) restorations have been proposed to protect the surrounding dental tissues from demineralization through the release of fluoride and by buffering the acid attack from dental biofilms. In contrast, the lack of buffering by composite resin (CR) restorations has been suggested as a promoting factor for the development of secondary caries. METHODS The present study employed transversal microradiography and confocal microscopy based pH ratiometry to quantify mineral loss and map microscale pH gradients inside Streptococcus mutans biofilms grown on compound specimens consisting of enamel, dentin and either GIC or CR. RESULTS Mineral loss in dentin was significantly lower next to GIC than next to CR, but no significant differences in local biofilm pH were observed between the two restorative materials. SIGNIFICANCE The cariostatic effect of GIC relies predominantly on the provision of fluoride and not on a direct buffering action. The lack of buffering by CR did not affect local biofilm pH and may therefore be of minor importance for secondary caries development.
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Affiliation(s)
- Sebastian Schlafer
- Section for Oral Ecology and Caries Control, Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark.
| | - Tanja Bornmann
- Section for Oral Ecology and Caries Control, Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark; Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
| | - Sebastian Paris
- Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
| | - Gerd Göstemeyer
- Department of Operative and Preventive Dentistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Aßmannshauser Straße 4-6, 14197 Berlin, Germany.
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Kristensen MF, Frandsen Lau E, Schlafer S. Ratiometric imaging of extracellular pH in Streptococcus mutans biofilms exposed to different flow velocities and saliva film thicknesses. J Oral Microbiol 2021; 13:1949427. [PMID: 34349890 PMCID: PMC8291056 DOI: 10.1080/20002297.2021.1949427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 11/22/2022] Open
Abstract
Introduction: Fluid flow has a prominent influence on the metabolism of surface-attached biofilms. Dental biofilms are covered by a thin saliva film that flows at different rates in different locations under stimulated and unstimulated conditions. Methods:The present study employed pH ratiometry to study the impact of different flow velocities, saliva film thicknesses and saliva concentrations on microscale pH developments in Streptococcus mutans biofilms of different age. Results:While saliva flow at a velocity of 0.8 mm/min (unstimulated flow) had little impact on biofilm pH, stimulated flow (8 mm/min; 80 mm/min) affected vertical pH gradients in the biofilms and raised the average pH in 48-h biofilms, but not in 72-h and 168-h biofilms. The saliva film thickness had a strong impact on biofilm pH under both static and dynamic conditions. pH drops were significantly higher in biofilms exposed to a thin saliva film (≤ 50 µm) than a thick saliva film (> 50 µm). pH drops in the biofilms were also strongly dependent on the saliva concentration and thus the buffer capacity of the salivary medium. For 48-h and 72-h biofilms, but not for 168-h biofilms, pH drops in distinct microenvironments were more pronounced when the local biofilm thickness was high.
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Affiliation(s)
| | - Ellen Frandsen Lau
- Section for Periodontology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark
| | - Sebastian Schlafer
- Department of Dentistry and oral health, Aarhus University, Aarhus, Denmark
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Hollmann B, Perkins M, Chauhan VM, Aylott JW, Hardie KR. Fluorescent nanosensors reveal dynamic pH gradients during biofilm formation. NPJ Biofilms Microbiomes 2021; 7:50. [PMID: 34140515 PMCID: PMC8211749 DOI: 10.1038/s41522-021-00221-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/12/2021] [Indexed: 12/12/2022] Open
Abstract
Understanding the dynamic environmental microniches of biofilms will permit us to detect, manage and exploit these communities. The components and architecture of biofilms have been interrogated in depth; however, little is known about the environmental microniches present. This is primarily because of the absence of tools with the required measurement sensitivity and resolution to detect these changes. We describe the application of ratiometric fluorescent pH-sensitive nanosensors, as a tool, to observe physiological pH changes in biofilms in real time. Nanosensors comprised two pH-sensitive fluorophores covalently encapsulated with a reference pH-insensitive fluorophore in an inert polyacrylamide nanoparticle matrix. The nanosensors were used to analyse the real-time three-dimensional pH variation for two model biofilm formers: (i) opportunistic pathogen Pseudomonas aeruginosa and (ii) oral pathogen Streptococcus mutans. The detection of sugar metabolism in real time by nanosensors provides a potential application to identify therapeutic solutions to improve oral health.
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Affiliation(s)
- Birte Hollmann
- Biodiscovery Institute, School of Life Sciences, University Park, University of Nottingham, Nottingham, UK
- Advanced Materials & Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Mark Perkins
- Biodiscovery Institute, School of Life Sciences, University Park, University of Nottingham, Nottingham, UK
- Advanced Materials & Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Veeren M Chauhan
- Advanced Materials & Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Jonathan W Aylott
- Advanced Materials & Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Kim R Hardie
- Biodiscovery Institute, School of Life Sciences, University Park, University of Nottingham, Nottingham, UK.
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Walther C, Zumbülte S, Faerber CM, Wierichs RJ, Meyer-Lueckel H, Conrads G, Henne K, Esteves-Oliveira M. Analysis of relative bacterial activity and lactate dehydrogenase gene expression of caries-associated bacteria in a site-specific natural biofilm: an ex vivo study. Clin Oral Investig 2020; 25:3669-3679. [PMID: 33226500 PMCID: PMC8137627 DOI: 10.1007/s00784-020-03691-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/10/2020] [Indexed: 11/30/2022]
Abstract
Objectives Detecting bacterial activity is considered a promising approach to monitor shifts from symbiosis to dysbiosis in oral microbiome. The present study aimed at investigating both the relative bacterial activity and the lactate dehydrogenase (ldh) gene expression of caries-associated bacteria in a site-specific natural biofilm. Material and methods Sixty subjects (age, mean ± SE: 30.1 ± 1.4) were allocated to two groups: caries-free subjects (CF) or caries-active subjects (CA). CF presented one sound surface (CFS, n = 30). CA presented two donor sites: a cavitated caries lesion (CAC, n = 30) and a sound reference surface (CAS, n = 30). Real-time quantitative PCR (q-PCR) on species or genus level and total bacteria was performed targeting the 16S gene, the 16S rRNA, the ldh gene, and the ldh mRNA (increasing 16S ribosomal RNA copy numbers can function as an indicator of increased energy metabolism). As the 16S rRNA abundance represents the number of ribosomes, while the 16S gene abundance represents the number of genomes, the quotient of the relative abundances functions as a measure for the relative bacterial activity (%). Results Both lactobacilli and S. mutans showed the highest relative bacterial activity in CAC ((mean ± SE) 218 ± 60% and 61 ± 16%, respectively) and the lowest values for both sound reference surfaces (69 ± 48%; 8 ± 3%). Significant differences were found between CAC and CAS as well as between CAC and CFS for both lactobacilli and S. mutans (p < 0.05). The ldh gene expression of lactobacilli and S. mutans only showed moderate values in CAC (1.90E+03 ± 2.11E+03; 2.08E+04 ± 4.44E+04 transcripts/μl) and CFS (2.04E+03 ± 2.74E+03; 8.16E+03 ± 6.64E+03 transcripts/μl); consequently no significant differences were detected. Conclusion and clinical relevance Caries-associated bacteria (lactobacilli and S. mutans) showed the highest relative bacterial activity in plaque of cavitated lesions, the lowest in sound surfaces, allowing the detection of a significant activity shift in health and disease for caries-active patients. However, no significant differences in ldh gene expression could be determined.
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Affiliation(s)
- Carolin Walther
- Department of Prosthetic Dentistry, Center for Dental and Oral Medicine, University Medical Center, Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
| | - Sandra Zumbülte
- Division of Oral Microbiology and Immunology, Department of Operative Dentistry, Periodontology, and Preventive Dentistry, RWTH Aachen University, Aachen, Germany
| | - Christoph M Faerber
- Department of Operative Dentistry, Periodontology, and Preventive Dentistry, RWTH Aachen University, Aachen, Germany
| | - Richard Johannes Wierichs
- Department of Restorative, Preventive and Pediatric Dentistry, zmk bern, University of Bern, Bern, Switzerland
| | - Hendrik Meyer-Lueckel
- Department of Restorative, Preventive and Pediatric Dentistry, zmk bern, University of Bern, Bern, Switzerland
| | - Georg Conrads
- Division of Oral Microbiology and Immunology, Department of Operative Dentistry, Periodontology, and Preventive Dentistry, RWTH Aachen University, Aachen, Germany
| | - Karsten Henne
- Division of Oral Microbiology and Immunology, Department of Operative Dentistry, Periodontology, and Preventive Dentistry, RWTH Aachen University, Aachen, Germany
| | - Marcella Esteves-Oliveira
- Department of Operative Dentistry, Periodontology, and Preventive Dentistry, RWTH Aachen University, Aachen, Germany.,Department of Cariology, Endodontology and Periodontology, University of Leipzig, Leipzig, Germany
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Merkl P, Aschtgen MS, Henriques-Normark B, Sotiriou GA. Biofilm interfacial acidity evaluation by pH-Responsive luminescent nanoparticle films. Biosens Bioelectron 2020; 171:112732. [PMID: 33120233 PMCID: PMC7116521 DOI: 10.1016/j.bios.2020.112732] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022]
Abstract
Biofilms are dense bacterial colonies that may adhere to the surfaces of medical devices and are major contributors to infections. These colonies are characterized by a self-produced matrix of extracellular polymeric substances (EPS). Bacterial biofilms are difficult to treat with the commonly used antibiotics partially because of their poor diffusion through the EPS and therefore require new targeted strategies to effectively fight them. Biofilms may produce an acidic microenvironment which can be exploited to design such targeted treatment strategies. However, there is currently a lack of high-throughput ways to determine the acidity of biofilms at their interface with the medical device. Here, a novel all-inorganic pH responsive system is developed from luminescent carbonated hydroxyapatite nanoparticles doped with Eu3+ ions which can determine the biofilm acidity fluorometrically due to carbonate removal in acidic environments that directly affects the nanoparticle luminescence. The pH responsive nanoparticles are in-situ deposited during their production onto substrates on which a variety of clinically-relevant biofilms are grown. The acidity of their interfacial (micro)environment depends on the bacterial species and strain even when differences in biofilm biomass are considered.
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Affiliation(s)
- Padryk Merkl
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.
| | - Marie-Stephanie Aschtgen
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden; Department of Clinical Microbiology, Karolinska University Hospital, SE-171 76, Stockholm, Sweden; Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 639798, Singapore.
| | - Georgios A Sotiriou
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.
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Karygianni L, Ren Z, Koo H, Thurnheer T. Biofilm Matrixome: Extracellular Components in Structured Microbial Communities. Trends Microbiol 2020; 28:668-681. [PMID: 32663461 DOI: 10.1016/j.tim.2020.03.016] [Citation(s) in RCA: 533] [Impact Index Per Article: 133.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/16/2020] [Accepted: 03/25/2020] [Indexed: 02/04/2023]
Abstract
Biofilms consist of microbial communities embedded in a 3D extracellular matrix. The matrix is composed of a complex array of extracellular polymeric substances (EPS) that contribute to the unique attributes of biofilm lifestyle and virulence. This ensemble of chemically and functionally diverse biomolecules is termed the 'matrixome'. The composition and mechanisms of EPS matrix formation, and its role in biofilm biology, function, and microenvironment are being revealed. This perspective article highlights recent advances about the multifaceted role of the 'matrixome' in the development, physical-chemical properties, and virulence of biofilms. We emphasize that targeting biofilm-specific conditions such as the matrixome could lead to precise and effective antibiofilm approaches. We also discuss the limited knowledge in the context of polymicrobial biofilms, and the need for more in-depth analyses of the EPS matrix in mixed communities that are associated with many human infectious diseases.
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Affiliation(s)
- L Karygianni
- Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine University of Zurich, Zurich, Switzerland
| | - Z Ren
- Department of Orthodontics, Divisions of Pediatric Dentistry and Community of Oral Health, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA
| | - H Koo
- Department of Orthodontics, Divisions of Pediatric Dentistry and Community of Oral Health, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA; Center for Innovation and Precision Dentistry, University of Pennsylvania School of Dental Medicine, School of Engineering and Applied Sciences, Philadelphia, PA, USA
| | - T Thurnheer
- Clinic of Conservative and Preventive Dentistry, Center of Dental Medicine University of Zurich, Zurich, Switzerland.
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Kristensen MF, Leonhardt D, Neland MLB, Schlafer S. A 3D printed microfluidic flow-cell for microscopy analysis of in situ-grown biofilms. J Microbiol Methods 2020; 171:105876. [PMID: 32087186 DOI: 10.1016/j.mimet.2020.105876] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 02/07/2023]
Abstract
Biofilm phenomena ranging from metabolic processes to attachment, detachment and quorum sensing are influenced by the fluid flow across the biofilm. A number of commercially available flow-cells allow for microscopy analysis of laboratory biofilms under flow, but there is a lack of shear controlled microfluidic devices that accommodate biofilms grown in situ on carriers or tissue samples. Therefore, we developed a flow-cell with adjustable geometry for microscopy analysis of in situ-grown biofilm samples under shear-controlled flow. The flow-cells were designed as one-piece disposable models, 3D-printed in resin and sealed with a coverslip after insertion of the biofilm sample. As a proof of concept, we studied the impact of stimulated saliva flow on pH developments in in situ-grown dental biofilms exposed to sucrose. Under static conditions, pH dropped in the biofilms, with pronounced differences between individual biofilms, but also between different microscopic fields of view within one biofilm. pH in the top layer of the biofilms tended to be lower than pH in the bottom layer. Under conditions of stimulated saliva flow (5 mm/min), pH rose to neutral or slightly alkaline values in all biofilms, and the vertical gradients were reversed, with the biofilm bottom becoming more acidic than the top. Hence, the present work demonstrates the importance of flow for the study of pH in dental biofilms.
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Affiliation(s)
- Mathilde Frost Kristensen
- Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark..
| | - Dirk Leonhardt
- Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark..
| | | | - Sebastian Schlafer
- Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000 Aarhus C, Denmark..
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Fulaz S, Hiebner D, Barros CHN, Devlin H, Vitale S, Quinn L, Casey E. Ratiometric Imaging of the in Situ pH Distribution of Biofilms by Use of Fluorescent Mesoporous Silica Nanosensors. ACS APPLIED MATERIALS & INTERFACES 2019; 11:32679-32688. [PMID: 31418546 DOI: 10.1021/acsami.9b09978] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Biofilms are communities of microorganisms enclosed in a self-generated matrix of extracellular polymeric substances. While biofilm recalcitrance and persistence are caused by several factors, a reduction in antimicrobial susceptibility has been closely associated with the generation of pH gradients within the biofilm structure. Cells embedded within the biofilm create a localized acidic microenvironment, which is unaffected by the external pH. Therefore, pH monitoring is a promising approach for understanding the complexities of a three-dimensional heterogeneous biofilm. A fluorescent pH nanosensor was designed through the synthesis of mesoporous silica nanoparticles (47 ± 5 nm diameter) conjugated to a pH-sensitive dye (fluorescein) and a pH-insensitive dye (rhodamine B) as an internal standard (dye-MSNs). The fluorescence intensity of fluorescein (IF) reduced significantly as the pH was decreased from 8.5 to 3.5. In contrast, the fluorescence intensity of rhodamine B (IR) remained constant at any pH. The ratio of IF/IR produced a sigmoidal curve with respect to the pH, in a working pH range between 4.5 and 7.5. Dye-MSNs enabled the measurement of pH gradients within Pseudomonas fluorescens WCS 365 biofilm microcolonies. The biofilms showed spatially distinct low-pH regions that were enclosed into large clusters corresponding to high-cell-density areas. Also present were small low-pH areas that spread indistinctly throughout the microcolony caused by the mass transfer effect. The lowest detected pH within the inner core of the microcolonies was 5.1, gradually increasing to a neutral pH toward the exterior of the microcolonies. The dye-MSNs were able to fully penetrate the biofilm matrix and allowed a quantitative ratiometric analysis of pH gradients and distribution throughout the biofilm, which was independent of the nanoparticle concentration.
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Affiliation(s)
- Stephanie Fulaz
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Dishon Hiebner
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Caio H N Barros
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Henry Devlin
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Stefania Vitale
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Laura Quinn
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
| | - Eoin Casey
- UCD School of Chemical and Bioprocess Engineering , University College Dublin , Belfield, Dublin 4 Dublin , Ireland
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