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  • 1.
    Alshammari, Hatem
    et al.
    Malmö universitet, Odontologiska fakulteten (OD). University of Hail, Saudi Arabia.
    Bakitian, Fahad
    Umm Al-Qura University, Saudi Arabia.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD).
    Andersen, Ole Zoffmann
    Elos Medtech, Denmark..
    Stavropoulos, Andreas
    Malmö universitet, Odontologiska fakulteten (OD). University of Geneva, Switzerland.
    Antimicrobial Properties of Strontium Functionalized Titanium Surfaces for Oral Applications, A Systematic Review2021Ingår i: Coatings, ISSN 2079-6412, Vol. 11, nr 7, artikel-id 810Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The aim of this systematic review was to assess the current scientific evidence of the antimicrobial potential of strontium (Sr) when used to functionalize titanium (Ti) for oral applications. Out of an initial list of 1081 potentially relevant publications identified in three electronic databases (MEDLINE via PubMed, Scopus, and Cochrane) up to 1 February 2021, nine publications based on in vitro studies met the inclusion criteria. The antimicrobial potential of Sr was investigated on different types of functionalized Ti substrates, employing different application methods. Nine studies reported on the early, i.e., 6-24 h, and two studies on the late, i.e., 7-28 days, antimicrobial effect of Sr, primarily against Staphylococcus aureus (S. aureus) and/or Escherichia coli (E. coli). Sr-modified samples demonstrated relevant early antimicrobial potential against S. aureus in three studies; only one of which presented statistical significance values, while the other two presented only the percentage of antimicrobial rate and biofilm inhibition. A relevant late biofilm inhibition potential against S. aureus of 40% and 10%-after 7 and 14 days, respectively-was reported in one study. Combining Sr with other metal ions, i.e., silver (Ag), zinc (Zn), and fluorine (F), demonstrated a significant antimicrobial effect and biofilm inhibition against both S. aureus and E. coli. Sr ion release within the first 24 h was generally low, i.e., below 50 mu g/L and 0.6 ppm; however, sustained Sr ion release for up to 30 days, while maintaining up to 90% of its original content, was also demonstrated. Thus, in most studies included herein, Sr-functionalized Ti showed a limited immediate (i.e., 24 h) antimicrobial effect, likely due to a low Sr ion release; however, with an adequate Sr ion release, a relevant antimicrobial effect, as well as a biofilm inhibition potential against S. aureus-but not E. coli-was observed at both early and late timepoints. Future studies should assess the antimicrobial potential of Ti functionalized with Sr against multispecies biofilms associated with peri-implantitis.

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  • 2.
    Alshammari, Hatem
    et al.
    Malmö universitet, Odontologiska fakulteten (OD).
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Stavropoulos, Andreas
    Malmö universitet, Odontologiska fakulteten (OD). University of Geneva, Switzerland.
    Antimicrobial Potential of Strontium Hydroxide on Bacteria Associated with Peri-Implantitis2021Ingår i: Antibiotics, ISSN 0066-4774, E-ISSN 2079-6382, Vol. 10, nr 2, artikel-id 150Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Peri-implantitis due to infection of dental implants is a common complication that may cause significant patient morbidity. In this study, we investigated the antimicrobial potential of Sr(OH)2 against different bacteria associated with peri-implantitis. Methods: The antimicrobial potential of five concentrations of Sr(OH)2 (100, 10, 1, 0.1, and 0.01 mM) was assessed with agar diffusion test, minimal inhibitory concentration (MIC), and biofilm viability assays against six bacteria commonly associated with biomaterial infections: Streptococcus mitis, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Escherichia coli, and Fusobacterium nucleatum. Results: Zones of inhibition were only observed for, 0.01, 0.1, and 1 mM of Sr(OH)2 tested against P. gingivalis, in the agar diffusion test. Growth inhibition in planktonic cultures was achieved at 10 mM for all species tested (p < 0.001). In biofilm viability assay, 10 and 100 mM Sr(OH)2 showed potent bactericidal affect against S. mitis, S. epidermidis, A. actinomycetemcomitans, E. coli, and P. gingivalis. Conclusions: The findings of this study indicate that Sr(OH)2 has antimicrobial properties against bacteria associated with peri-implantitis. 

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  • 3. Bikker, Floris J.
    et al.
    Hoogenkamp, Michel A.
    Malhaoui, Amine
    Nazmi, Kamran
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD).
    Krom, Bastiaan P.
    Phytosphingosine Prevents the Formation of Young Salivary Biofilms in vitro2018Ingår i: Caries Research, ISSN 0008-6568, E-ISSN 1421-976X, Vol. 52, nr 1-2, s. 7-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dental biofilms are formed in a multistep process that is initiated by the adhesion of oral bacteria to the dental hard surface. As dental biofilms are associated with oral diseases their control is necessary in order to maintain oral health. Recently, it was revealed that phytosphingosine (PHS)-treated hydroxyapatite discs showed anti-adhesive activity in a static in vitro biofilm model against Streptococcus mutans. The goal of the present study was to further unravel the anti-adhesive and anti-biofilm properties of PHS in both static and dynamic in vitro biofilm models against a full salivary inoculum. After 3 h under static conditions, bacterial adherence on PHS-treated cover glass slides was reduced by 60% compared to the untreated surface. After 6 and 24 h under static conditions, no significant differences in bacterial adherence were observed between PHS-treated and untreated cover glass slides. However, under dynamic conditions, i.e., the presence of shear forces, virtually no bacterial adherence was observed for up to 16 h on PHS-coated surfaces. Besides, PHS showed a strong bactericidal activity on salivary biofilms. Treatment of a 3- and 6-h statically grown biofilm resulted in a 99 and 94% reduction of viable cells, respectively, which was effectuated within minutes. In principle, these anti-adherence and anti-biofilm properties make PHS a promising candidate ingredient for use in oral care products aimed at oral microbial control. (C) 2017 S. Karger AG, Basel

  • 4.
    Boisen, Gabriella
    et al.
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Davies, Julia R
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Acid tolerance in early colonizers of oral biofilms2021Ingår i: BMC Microbiology, E-ISSN 1471-2180, Vol. 21, nr 1, artikel-id 45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A. naeslundii and A. odontolyticus) and examined the role of salivary proteins in acid tolerance development.

    METHODS: Biofilms were formed on surfaces in Ibidi® mini flow cells with or without a coating of salivary proteins and acid tolerance assessed by exposing them to a challenge known to kill non-acid tolerant cells (pH 3.5 for 30 min) followed by staining with LIVE/DEAD BacLight and confocal scanning laser microscopy. The ability to induce an ATR was assessed by exposing the biofilms to an adaptation pH (pH 5.5) for 2 hours prior to the low pH challenge.

    RESULTS: Biofilm formation significantly increased acid tolerance in all the clinical streptococcal strains (P < 0.05) whereas the laboratory strains varied in their response. In biofilms, S. oralis was much more acid tolerant than S. gordonii or S. mutans. A. naeslundii showed a significant increase in acid tolerance in biofilms compared to planktonic cells (P < 0.001) which was not seen for A. odontolyticus. All strains except S. oralis induced an ATR after pre-exposure to pH 5.5 (P < 0.05). The presence of a salivary pellicle enhanced both acid tolerance development and ATR induction in S. gordonii biofilms (P < 0.05) but did not affect the other bacteria to the same extent.

    CONCLUSIONS: These findings suggest that factors such as surface contact, the presence of a salivary pellicle and sensing of environmental pH can contribute to the development of high levels of acid tolerance amongst early colonizers in oral biofilms which may be important in the initiation of caries.

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  • 5. Charyeva, Olga
    et al.
    Neilands, Jessica
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Wennerberg, Ann
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Bacterial Biofilm Formation on Resorbing Magnesium Implants2015Ingår i: Open Journal of Medical Microbiology, ISSN 2165-3372, Vol. 5, nr 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Implant-associated infections are a result of bacterial adhesion to an implant surface and subsequent biofilm formation at the implantation site. This study compares different magnesium materials based on their ability to resist bacterial adhesion as well as further biofilm formation. Material and Methods: The surfaces of four magnesium-based materials (Mg2Ag, Mg10Gd, WE43 and 99.99% pure Mg) were characterized using atomic force microscope. In addition, the samples were tested for their ability to resist biofilm formation. Planktonic bacteria of either S. epidermidis or E. faecalis were allowed to adhere to the magnesium surfaces for two hour followed by rinsing and, for S. epidermidis, further incubation of 24, 72 and 168 h was carried out. Results: E. faecalis had a significantly stronger adhesion to all magnesium surfaces compared to S. epidermidis (p = 0.001). Biofilm growth of S. epidermidis was different on various magnesium materials: the amount of bacteria increased up to 72 h but interestingly a significant decrease was seen at 168 h on Mg2Ag and WE43 surfaces. For pure Mg and Mg10Gd the biofilm formation reached plateau at 72 h. Surface characteristics of resorbable magnesium materials were changing over time, and the surface was generally less rough at 168 h compared to earlier time points. No correlation was found between the surface topology and the amount of adherent bacteria. Conclusion: In early stages of biofilm adhesion, no differences between magnesium materials were observed. However, after 72 h Mg2Ag and WE43 had the best ability to suppress S. epidermidis’ biofilm formation. Also, bacterial adhesion to magnesium materials was not dependent on samples’ surface topology.

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  • 6.
    Davies, Julia R
    et al.
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Kad, Trupti
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Kinnby, B
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Prgomet, Zdenka
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Bengtsson, Torbjörn
    School of Medical Sciences, Örebro University, Örebro, Sweden..
    Khalaf, Hazem
    School of Medical Sciences, Örebro University, Örebro, Sweden..
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Polymicrobial synergy stimulates Porphyromonas gingivalis survival and gingipain expression in a multi-species subgingival community.2021Ingår i: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 21, nr 1, artikel-id 639Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Dysbiosis in subgingival microbial communities, resulting from increased inflammatory transudate from the gingival tissues, is an important factor in initiation and development of periodontitis. Dysbiotic communities are characterized by increased numbers of bacteria that exploit the serum-like transudate for nutrients, giving rise to a proteolytic community phenotype. Here we investigate the contribution of interactions between members of a sub-gingival community to survival and development of virulence in a serum environment-modelling that in the subgingival pocket.

    METHODS: Growth and proteolytic activity of three Porphyromonas gingivalis strains in nutrient broth or a serum environment were assessed using A600 and a fluorescent protease substrate, respectively. Adherence of P. gingivalis strains to serum-coated surfaces was studied with confocal microscopy and 2D-gel electrophoresis of bacterial supernatants used to investigate extracellular proteins. A model multi-species sub-gingival community containing Fusobacterium nucleatum, Streptococcus constellatus, Parvimonas micra with wild type or isogenic mutants of P. gingivalis was then created and growth and proteolytic activity in serum assessed as above. Community composition over time was monitored using culture techniques and qPCR.

    RESULTS: The P. gingivalis strains showed different growth rates in nutrient broth related to the level of proteolytic activity (largely gingipains) in the cultures. Despite being able to adhere to serum-coated surfaces, none of the strains was able to grow alone in a serum environment. Together in the subgingival consortium however, all the included species were able to grow in the serum environment and the community adopted a proteolytic phenotype. Inclusion of P. gingivalis strains lacking gingipains in the consortium revealed that community growth was facilitated by Rgp gingipain from P. gingivalis.

    CONCLUSIONS: In the multi-species consortium, growth was facilitated by the wild-type and Rgp-expressing strains of P. gingivalis, suggesting that Rgp is involved in delivery of nutrients to the whole community through degradation of complex protein substrates in serum. Whereas they are constitutively expressed by P. gingivalis in nutrient broth, gingipain expression in the model periodontal pocket environment (serum) appeared to be orchestrated through signaling to P. gingivalis from other members of the community, a phenomenon which then promoted growth of the whole community.

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  • 7. Hall, Jan
    et al.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Davies, Julia R
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Ekestubbe, Annika
    Friberg, Bertil
    The Brånemark Clinic, Public Dental Health Service, Västra Götaland, Gothenburg, Sweden.
    A randomized, controlled, clinical study on a new titanium oxide abutment surface for improved healing and soft tissue health2019Ingår i: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 21, nr Suppl 1, s. 55-68Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: A newly developed, anodized titanium oxide surface containing anatase has been reported to have antimicrobial properties that could reduce bacterial adherence to abutments. Purpose: To investigate if abutments with the anodized surface improve healing and soft tissue health in a randomized controlled study. Materials and Methods: Test abutments with a nanostructured anodized surface were compared with control machined titanium abutments. In total, 35 subjects each received a pair of test and control abutments. The primary endpoint was reduction of biofilm formation at test abutments at the 6‐week follow‐up. Secondary endpoints included several soft tissue assessments. qPCR for gene markers was used to indirectly evaluate healing and soft tissue health. Results: No significant differences in biofilm formation were observed between test and control abutments, but soft tissue bleeding upon abutment removal was significantly lower for test abutments compared with control abutments (P = 0.006) at 6 weeks. Keratinized mucosa height was significantly greater at test abutments compared with control abutments at the 6‐week, 6‐month, and 2‐year follow‐ups. Significant gene expression differences indicated differences in healing and tissue remodeling. Conclusions: Abutments with an anodized and nanostructured surface compared with a conventional, machined titanium surface had no significant effect on bacterial colonization and proteolytic activity but were associated with better soft tissue outcomes such as a lower bleeding index at abutment removal and consistently greater height of keratinized mucosa throughout the 2‐year follow‐up, suggesting improved surface‐dependent peri‐implant healing and soft tissue health.

  • 8.
    Havsed, Kristian
    et al.
    Malmö universitet, Odontologiska fakulteten (OD). Department of Pediatric Dentistry, Institute for Postgraduate Dental Education, Jönköping, Sweden; Centre for Oral Health, School of Health and Welfare, Jönköping University, Jönköping, Sweden.
    Stensson, Malin
    Centre for Oral Health, School of Health and Welfare, Jönköping University, Jönköping, Sweden; Folktandvården Skåne, The Swedish Dental Service of Skåne, Lund, Sweden.
    Jansson, Henrik
    Malmö universitet, Odontologiska fakulteten (OD). Centre for Oral Health, School of Health and Welfare, Jönköping University, Jönköping, Sweden; Folktandvården Skåne, The Swedish Dental Service of Skåne, Lund, Sweden.
    Carda-Diéguez, Miguel
    Department of Health & Genomics, Foundation for the Promotion of Health and Biomedical Research (FISABIO) Foundation, Valencia, Spain.
    Pedersen, Anders
    Swedish NMR Centre, The University of Gothenburg, Gothenburg, Sweden.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Mira, Alex
    Centre for Oral Health, School of Health and Welfare, Jönköping University, Jönköping, Sweden; Department of Health & Genomics, Foundation for the Promotion of Health and Biomedical Research (FISABIO) Foundation, Valencia, Spain.
    Bacterial Composition and Metabolomics of Dental Plaque From Adolescents2021Ingår i: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 11, artikel-id 716493Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Supragingival dental plaque samples were collected from 40 Swedish adolescents, including 20 with caries lesions (CAR) and 20 caries-free (CF). Fresh plaque samples were subjected to an ex vivo acid tolerance (AT) test where the proportion of bacteria resistant to an acid shock was evaluated through confocal microscopy and live/dead staining, and the metabolites produced were quantified by 1H Nuclear Magnetic Resonance (1H NMR). In addition, DNA was extracted and the 16S rRNA gene was sequenced by Illumina sequencing, in order to characterize bacterial composition in the same samples. There were no significant differences in AT scores between CAR and CF individuals. However, 7 out of the 10 individuals with highest AT scores belonged to the CAR group. Regarding bacterial composition, Abiotrophia, Prevotella and Veillonella were found at significantly higher levels in CAR individuals (p=0.0085, 0.026 and 0.04 respectively) and Rothia and Corynebacterium at significantly higher levels in CF individuals (p=0.026 and 0.003). The caries pathogen Streptococcus mutans was found at low frequencies and was absent in 60% of CAR individuals. Random-forest predictive models indicate that at least 4 bacterial species or 9 genera are needed to distinguish CAR from CF adolescents. The metabolomic profile obtained by NMR showed a significant clustering of organic acids with specific bacteria in CAR and/or high AT individuals, being Scardovia wiggsiae the species with strongest associations. A significant clustering of ethanol and isopropanol with health-associated bacteria such as Rothia or Corynebacterium was also found. Accordingly, several relationships involving these compounds like the Ethanol : Lactate or Succinate : Lactate ratios were significantly associated to acid tolerance and could be of predictive value for caries risk. We therefore propose that future caries risk studies would benefit from considering not only the use of multiple organisms as potential microbial biomarkers, but also their functional adaptation and metabolic output.

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  • 9.
    Hix Janssens, Thomas
    et al.
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Shinde, Sudhirkumar
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Abouhany, Rahma
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Davies, Julia R
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Sellergren, Börje
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Microcontact-Imprinted Optical Sensors for Virulence Factors of Periodontal Disease2023Ingår i: ACS Omega, E-ISSN 2470-1343, Vol. 8, nr 17, s. 15259-15265Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Periodontitis (gum disease) is a common biofilm-mediated oral condition, with around 7% of the adult population suffering from severe disease with risk for tooth loss. Moreover, periodontitis virulence markers have been found in atherosclerotic plaque and brain tissue, suggesting a link to cardiovascular and Alzheimer’s diseases. The lack of accurate, fast, and sensitive clinical methods to identify patients at risk leads, on the one hand, to patients being undiagnosed until the onset of severe disease and, on the other hand, to overtreatment of individuals with mild disease, diverting resources from those patients most in need. The periodontitis-associated bacterium, Porphyromonas gingivalis, secrete gingipains which are highly active proteases recognized as key virulence factors during disease progression. This makes them interesting candidates as predictive biomarkers, but currently, there are no methods in clinical use for monitoring them. Quantifying the levels or proteolytic activity of gingipains in the periodontal pocket surrounding the teeth could enable early-stage disease diagnosis. Here, we report on a monitoring approach based on high-affinity microcontact imprinted polymer-based receptors for the Arg and Lys specific gingipains Rgp and Kgp and their combination with surface plasmon resonance (SPR)-based biosensor technology for quantifying gingipain levels in biofluids and patient samples. Therefore, Rgp and Kgp were immobilized on glass coverslips followed by microcontact imprinting of poly-acrylamide based films anchored to gold sensor chips. The monomers selected were N-isopropyl acrylamide (NIPAM), N-hydroxyethyl acrylamide (HEAA) and N-methacryloyl-4-aminobenzamidine hydrochloride (BAM), with N,N′-methylene bis(acrylamide) (BIS) as the crosslinker. This resulted in imprinted surfaces exhibiting selectivity towards their templates high affinity and selectivity for the templated proteins with dissociation constants (Kd) of 159 and 299 nM for the Rgp- and Kgp-imprinted, surfaces respectively. The former surface displayed even higher affinity (Kd = 71 nM) when tested in dilute cell culture supernatants. Calculated limits of detection for the sensors were 110 and 90 nM corresponding to levels below clinically relevant concentrations.

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  • 10.
    Neilands, J
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Svensäter, G
    Malmö högskola, Odontologiska fakulteten (OD).
    Acid tolerance in streptococcal biofilm cells (Malmö)2008Konferensbidrag (Övrigt vetenskapligt)
  • 11.
    Neilands, J
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Svensäter, G
    Malmö högskola, Odontologiska fakulteten (OD).
    Acid tolerance in streptococcal biofilm cells (Toronto)2008Konferensbidrag (Övrigt vetenskapligt)
  • 12.
    Neilands, Jessica
    Malmö högskola, Odontologiska fakulteten (OD).
    Acid Tolerance of Streptococcus Mutans Biofilms2007Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Mikrobiologisk forskning har till stor del bedrivits genom att man odlat bakterier i näringslösningar och på agarplattor och sedan studera bakterierna på olika sätt. Detta sätt att odla bakterier överensstämmer inte särskilt bra med hur bakterier växer i verkligenheten. I naturen växer bakterier fastsittande på olika typer av ytor (tandemalj, epitel, stenar, plastytor etc.) i s.k. biofilmer. Det har visat sig att bakterier i biofilmer inte alls beter sig som bakterier som växer fritt i en näringslösning (planktonisk form). Biofilmbak-terier skiljer sig från planktoniska bakterier genom att de är mer resistenta mot antibiotika och biocider. De är mer stresståliga, de växer långsammare och de har ett annorlunda gen- och proteinuttryck. Sammantaget har biofilmbakterier andra egenskaper. På grund av detta, har fokus inom mikrobiologisk forskning det senaste decenniet riktats mot att studera biofilmer för att komma närmare bakteriernas verklighet. I munnen växer bakterierna i biofilmer. Bakterierna i munnen är nödvändiga för att god munhälsa men de är också orsak till två av världens vanligaste sjukdomar; karies och parodontit. Streptococcus mutans tillhör den normala munfloran men medverkar också till att karies utvecklas. Karies uppstår när det blir en obalans i det orala ekosystemet. När man äter sjunker pH i munnen pga att bakterierna i plack producerar syror när de bryter ner kolhydrater. Om man äter ofta kommer pH i plack att vara surt under längre perioder, vilket leder till en selektion av bakterier som är stresståliga och kan anpassa sig till den sura miljön. Detta resulterar i att en syratolerant mikroflora dominerar i placket. Dessa bakterier har i sin tur kapacitet att göra det ännu surare i placket under långa perioder. Detta kan leda till demineralisering av emaljen och upp-komst av karies. S. mutans anpassar sig till en sur miljö genom att inducera en syratoleransrespons (ATR) vid subletala pH-värden. Syftet med denna avhandling var att studera hur S. mutans beter sig när den växer i biofilmer och ta reda på mer om syratoleransresponsen i S. mutans biofilmer. Resultaten från avhandlingen visar att S. mutans bakterier som vuxit i en biofilm i tre dagar har ett annorlunda proteinuttryck än planktoniska bakterier och att förändringar i proteinuttryck sker redan efter två timmar av ytkontakt. Proteinuttrycket ändras efter hand som biofilmen växer och blir äldre. Biofilmbakterierna visade sig också vara många gånger mer syratoleranta än de planktoniska bakterierna och ytkontakt i sig var viktigt för den ökade syratole-ransen. Äldre biofilmer (3 dagar) var mer syratoleranta än unga biofilmer (3 timmar) vilket kan bero på att de utsatts för pH chocker under växt i biofilmen och därmed inducerat en ATR. Unga biofilmer inducerade en ATR när de utsattes för pH 5.5 i tre timmar och denna ATR kunde inhiberas genom tillsats av fluor. Det visade sig också att olika stammar av S. mutans var olika syra-toleranta och hade olika förmåga att inducera en ATR. Detta kan i praktiken innebära att människor med bakterier som är mer benägna att inducera en ATR löper större risk att utveckla karies. Genom att förhindra induceringen av ATR skulle man alltså kunna förhindra utvecklingen av karies.

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    Comprehensive Summary
  • 13.
    Neilands, Jessica
    Malmö högskola, Odontologiska fakulteten (OD).
    Karies och den ekologiska plackhypotesen2008Ingår i: Tandläkartidningen, ISSN 0039-6982, Vol. 100, nr 6, s. 58-60Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Bakterier i biofilmer beter sig inte alls som bakterier som växer fritt i en näringslösning. Genom att studera biofilmer kommer man närmare bakteriernas verklighet och plack är nog den mest studerade biofilmen. Studien visar att människor med bakterier som är mer benägna att utlösa en syratoleransrespons löper större risk att utveckla karies.

  • 14.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Bikker, Floris
    Kinnby, Bertil
    Malmö högskola, Odontologiska fakulteten (OD).
    PAI-2/SerpinB2 Inhibits Proteolytic Activity in a P. gingivalis-dominated Multispecies Bacterial Consortium2016Ingår i: Archives of Oral Biology, ISSN 0003-9969, E-ISSN 1879-1506, Vol. 70, s. 1-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective The aim of this study was to investigate the ability of the serine protease inhibitor plasminogen activator inhibitor type 2 (PAI-2/Serpin B2) to inhibit proteases produced by a multispecies bacterial consortium in vitro. Background Gingival and periodontal inflammation is associated with an increased flow of protein-rich gingival fluid. This nutritional change in the microenvironment favors bacteria with a proteolytic phenotype, triggering inflammation and associated tissue breakdown. PAI-2 is produced by macrophages and keratinocytes and is present in very high concentrations in gingival crevicular fluid; the highest level in the body. Design A multispecies bacterial consortium comprising nine bacterial strains, resembling the conditions in a periodontal pocket, was grown planktonically and as a biofilm. After seven days PAI-2 was added to the consortium and the proteolytic activity was assayed with fluorogenic protease substrates; FITC-labeled casein to detect global protease activity, fluorescent H-Gly-Pro-AMC for serine protease activity and fluorescent BIKKAM-10 for Porphyromonas gingivalis-associated protease activity. Protease activity associated with biofilm cells was examined by confocal scanning laser microscopy. Results PAI-2 inhibited proteolytic activity of the bacterial consortium, as seen by decreased fluorescence of all substrates. PAI-2 specifically inhibited P. gingivalis proteolytic activity. Conclusion To our knowledge, this is the first time that PAI-2 has been shown to inhibit bacterial proteases. Given the high concentration of PAI-2 in the gingival region, our results indicate that PAI-2 might play a role for the integrity of the epithelial barrier.

  • 15.
    Neilands, Jessica
    et al.
    Malmö universitet, Odontologiska fakulteten (OD).
    Davies, Julia R
    Malmö universitet, Odontologiska fakulteten (OD).
    Bikker, Floris J
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD).
    Parvimonas micra stimulates expression of gingipains from Porphyromonas gingivalis in multi-species communities2019Ingår i: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 55, s. 54-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dental biofilms are complex ecosystems containing many bacterial species that live in mutualistic relationships. These interactions can profoundly affect the virulence properties of the community. In this study we investigated how the production of gingipains, virulence factors from Porphyromonas gingivalis important in periodontal disease, was affected by other commonly found members of the sub-gingival microbiome. To mimic the subgingival microbiome, multispecies consortia (P. gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Streptococus oralis, Streptococcus mitis, Streptococcus gordonii and Streptococcus cristatus, with or without Parvimonas micra) as well as dual species consortia (P. gingivalis with P. micra, S. oralis or F. nucleatum) were constructed and maintained anaerobically in 10% serum for up to seven days. The number of P. gingivalis was determined by plating on Brucella agar and the gingipain specific fluorogenic substrate BikKam-10 was used to investigate gingipain activity. The effect of secreted products from P. micra on gingipain activity was investigated by adding supernatants from P. micra to P. gingivalis cultures. The most prominent secreted proteins in the supernatant were identified using mass spectrometry. P. gingivalis was unable to grow in serum, either alone or in the presence of S. oralis or F. nucleatum. In contrast, with P. micra growth was significantly enhanced and this was associated with an increase in gingipain activity. In the multi-species consortia, the presence of P. micra caused a 13-fold increase in gingipain activity. Exposure of P. gingivalis to supernatants from P. micra for 24 hours caused a 3-fold increase in gingipain activity. This effect was reduced by 43% after heat-treatment of the supernatant. Two dimensional gel electrophoresis revealed that several of the most prominent proteins in the P. micra supernatant were glycolytic enzymes. The results from this study suggests that gingipains are produced in response to a P. micra derived signaling molecule that is most likely a protein. This is the first time it has been shown that P. micra can affect P. gingivalis virulence properties. This is likely to be of significance for the development of be of periodontitis since these two microorganisms are often found together in the subgingival biofilm.

  • 16.
    Neilands, Jessica
    et al.
    Malmö universitet, Odontologiska fakulteten (OD).
    Kinnby, B
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Porphyromonas gingivalis initiates coagulation and secretes polyphosphates: A mechanism for sustaining chronic inflammation?2022Ingår i: Microbial Pathogenesis, ISSN 0882-4010, E-ISSN 1096-1208, Vol. 162, s. 1-8, artikel-id 104648Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Periodontitis is a chronic inflammation resulting in destruction of tooth-supporting bone. Chronic inflammation is characterized by extravascular fibrin deposition. Fibrin is central to destruction of bone; monocytes bind to fibrin and form osteoclasts, thus providing a link between coagulation and the tissue destructive processes in periodontitis. The oral microbiome is essential to oral health. However, local ecological changes, such as increased biofilm formation, result in a dysbiotic microbiome characterized by an increase of protease-producing species e.g. Porphyromonas gingivalis. Proteases initiate inflammation and may cleave coagulation factors. Polyphosphates (polyP) may also provide bacteria with procoagulant properties similar to platelet-released polyP. P. gingivalis has also been found in remote locations related to vascular pathology and Alzheimer's disease.

    OBJECTIVES: The aim of this study was to investigate procoagulant activity of ten different species of oral bacteria present in oral health and disease as well as presence of polyP and fibrin formation in planktonic and biofilm bacteria.

    METHODS: Oral bacteria were studied for protease production and procoagulant activity. The presence of polyP and formation of fibrin was observed using confocal microscopy.

    RESULTS: P. gingivalis showed strong protease activity and was the only species exerting procoagulant activity. Confocal microscopy showed polyP intracellularly in planktonic bacteria and extracellularly after biofilm formation. Fibrin formation emanated from planktonic bacteria and from both bacteria and polyP in biofilm cultures.

    CONCLUSIONS: The procoagulant activity of P. gingivalis could explain its role in chronic inflammation, locally in oral tissues as well as in remote locations.

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  • 17.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Petersson, Lars Gunnar
    Beighton, David
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Fluoride-supplemented milk inhibits acid tolerance in root caries biofilms2012Ingår i: Caries Research, ISSN 0008-6568, E-ISSN 1421-976X, Vol. 46, nr 2, s. 156-160Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we investigated the effect of fluoride on plaque acid tolerance. The test group consumed 200 ml of milk supplemented with 5 mg F/l as NaF once a day, the milk control group drank 200 ml of unsupplemented milk, and the no-milk control group did not consume milk in this manner. Plaque samples were taken at baseline and after 15 months. The proportion of acid-tolerant bacteria in plaque was estimated using LIVE/DEAD® BacLight™ staining after exposure to pH 3.5 for 2 h. The fluoride group showed a statistically significant decrease in plaque acid tolerance compared to baseline. This study shows that daily intake of fluoride in milk reduces plaque acid tolerance.

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  • 18.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Sutherland, Donald
    Resin, Anton
    Wejse, Peter Langborn
    Chávez de Paz, Luis Eduardo
    Chitosan Nanoparticles Affect the Acid Tolerance Response in Adhered Cells of Streptococcus mutans2011Ingår i: Caries Research, ISSN 0008-6568, E-ISSN 1421-976X, Vol. 45, nr 6, s. 501-505Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we evaluated the effect of chitosan nanoparticles on the acid tolerance response (ATR) of adhered Streptococcus mutans. An ATR was induced by exposing S. mutans to pH 5.5 for 2 h and confirmed by exposing the acid-adapted cells to pH 3.5 for 30 min, with the majority of cells appearing viable according to the LIVE/DEAD® technique. However, when chitosan nanoparticles were present during the exposure to pH 5.5, no ATR occurred as most cells appeared dead after the pH 3.5 shock. We conclude that the chitosan nanoparticles tested had the ability to hinder ATR induction in adhered S. mutans.

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  • 19.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Acid Tolerance in Oral Biofilms2007Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 20.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Acid Tolerance of Biofilm Cells of Streptococcus mutans2007Ingår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 73, nr 17, s. 5633-5638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Streptococcus mutans, a member of the dental plaque community, has been shown to be involved in the carious process. Cells of S. mutans induce an acid tolerance response (ATR) when exposed to sublethal pH values that enhances their survival at a lower pH. Mature biofilm cells are more resistant to acid stress than planktonic cells. We were interested in studying the acid tolerance and ATR-inducing ability of newly adhered biofilm cells of S. mutans. All experiments were carried out using flow-cell systems, with acid tolerance tested by exposing 3-h biofilm cells to pH 3.0 for 2 h and counting the number of survivors by plating on blood agar. Acid adaptability experiments were conducted by exposing biofilm cells to pH 5.5 for 3 h and then lowering the pH to 3.5 for 30 min. The viability of the cells was assessed by staining the cells with LIVE/DEAD BacLight viability stain. Three-hour biofilm cells of three different strains of S. mutans were between 820- and 70,000-fold more acid tolerant than corresponding planktonic cells. These strains also induced an ATR that enhanced the viability at pH 3.5. The presence of fluoride (0.5 M) inhibited the induction of an ATR, with 77% fewer viable cells at pH 3.5 as a consequence. Our data suggest that adhesion to a surface is an important step in the development of acid tolerance in biofilm cells and that different strains of S. mutans possess different degrees of acid tolerance and ability to induce an ATR.

  • 21.
    Neilands, Jessica
    et al.
    Malmö universitet, Odontologiska fakulteten (OD).
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD).
    Boisen, Gabriella
    Malmö universitet, Odontologiska fakulteten (OD).
    Robertsson, Carolina
    Malmö universitet, Odontologiska fakulteten (OD).
    Wickström, Claes
    Malmö universitet, Odontologiska fakulteten (OD).
    Davies, Julia R
    Malmö universitet, Odontologiska fakulteten (OD).
    Formation and Analysis of Mono-species and Polymicrobial Oral Biofilms in Flow-Cell Models2023Ingår i: Bacterial Pathogenesis: Methods and Protocols,, Springer, 2023, s. 33-52Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The oral microbiota, which is known to include at least 600 different bacterial species, is found on the teethand mucosal surfaces as multi-species communities or biofilms. The oral surfaces are covered with a pellicleof proteins absorbed from saliva, and biofilm formation is initiated when primary colonizers, which expresssurface adhesins that bind to specific salivary components, attach to the oral tissues. Further developmentthen proceeds through co-aggregation of additional species. Over time, the composition of oral biofilms,which varies between different sites throughout the oral cavity, is determined by a combination ofenvironmental factors such as the properties of the underlying surface, nutrient availability and oxygenlevels, and bacterial interactions within the community. A complex equilibrium between biofilm communities and the host is responsible for the maintenance of a healthy biofilm phenotype (eubiosis). In the faceof sustained environmental perturbation, however, biofilm homeostasis can break down giving rise todysbiosis, which is associated with the development of oral diseases such as caries and periodontitis.In vitro models have an important part to play in increasing our understanding of the complex processesinvolved in biofilm development in oral health and disease, and the requirements for experimental system,microbial complexity, and analysis techniques will necessarily vary depending on the question posed. In thischapter we describe some current and well-established methods used in our laboratory for studying oralbacteria in biofilm models which can be adapted to suit the needs of individual users. 

  • 22.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Troedsson, Ulrika
    Malmö högskola, Odontologiska fakulteten (OD).
    Sjödin, Torgny
    Malmö högskola, Odontologiska fakulteten (OD).
    Davies, Julia
    Malmö högskola, Odontologiska fakulteten (OD).
    The effect of delmopinol and fluoride on acid adaptation and acid production in dental plaque biofilms2014Ingår i: Archives of Oral Biology, ISSN 0003-9969, E-ISSN 1879-1506, Vol. 59, nr 3, s. 318-323Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: To investigate the effect of delmopinol and fluoride alone or in combination on acid adaptation and acid production in plaque biofilm bacteria in vitro. DESIGN: The effect of delmopinol and fluoride on acid adaptation was tested by exposing the biofilm bacteria, grown in a mini-flow cell system under static conditions, to pH 5.5 overnight in the presence of 0.16 mM delmopinol, 1 mF NaF or a combination of both. The following day, acid adaptation was evaluated by exposing the cells to an acid challenge for 2h at a pH known to kill non-adapted cells (pH 2.5). The cells were stained using LIVE/DEAD BacLight Viability stain and the number of viable (acid tolerant) cells was determined using confocal scanning laser microscopy. Control cells were treated in the same manner but without the exposure to delmopinol or fluoride. How delmopinol and fluoride affected acid production was assessed by measuring the pH-drop after glucose pulsing in the presence of delmopinol and/or different concentrations of fluoride. RESULTS: Fluoride alone or in combination with delmopinol affected the acid adaptation and significantly reduced the acid tolerance of the plaque biofilm. This effect was more pronounced when the two compounds were combined. Delmopinol alone did not affect acid adaptation. A combination of delmopinol and fluoride also reduced acid production at concentrations where neither of the compounds in isolation had an effect. CONCLUSION: Fluoride and delmopinol can work synergistically to affect acid adaptation and acid production in plaque biofilm bacteria.

  • 23.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Wickström, Claes
    Malmö högskola, Odontologiska fakulteten (OD).
    Kinnby, Bertil
    Malmö högskola, Odontologiska fakulteten (OD).
    Davies, Julia R
    Malmö högskola, Odontologiska fakulteten (OD).
    Hall, Jan
    Friberg, Bertil
    Malmö högskola, Odontologiska fakulteten (OD).
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Bacterial profiles and proteolytic activity in peri-implantitis versus healthy sitesBacterial profiles and proteolytic activity in peri-implantitis versus healthy sites2015Ingår i: Anaerobe, ISSN 1075-9964, E-ISSN 1095-8274, Vol. 35, s. 28-34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Peri-implantitis is a biofilm-induced destructive inflammatory process that, over time, results in loss of supporting bone around an osseointegrated dental implant. Biofilms at peri-implantitis sites have been reported to be dominated by Gram-negative anaerobic rods with a proteolytic metabolism such as, Fusobacterium, Porphyromonas, Prevotella and Tannerella, as well as anaerobic Gram-positive cocci. In this study, we hypothesized that protease activity is instrumental in driving bone destruction and we therefore compared the microbial composition and level of protease activity in samples of peri-implant biofluid (PIBF) from 25 healthy subjects (H group) and 25 subjects with peri-implantitis (PI group). Microbial composition was investigated using culture techniques and protease activity was determined using a FITC-labelled casein substrate. The microbial composition was highly variable in subjects both in the H and PI groups but one prominent difference was the prevalence of Porphyromonas/Prevotella and anaerobic Gram positive cocci which was significantly higher in the PI than in the H group. A subgroup of subjects with peri-implantitis displayed a high level of protease activity in the PIBF compared to healthy subjects. However, this activity could not be related to the presence of specific bacterial species. We propose that a high level of protease activity may be a predictive factor for disease progression in peri-implantitis. Further longitudinal studies are however required to determine whether assessment of protease activity could serve as a useful method to identify patients at risk for progressive tissue destruction.

  • 24.
    Neilands, Jessica
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Wilkins, Joanna C
    Beighton, David
    Wrzesinski, Krzysztof
    Fey, Stephen J
    Mose-Larsen, Peter
    Hamilton, Ian R
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Effect of acid shock on protein expression by biofilm cells of Streptococcus mutans2003Ingår i: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 227, nr 2, s. 287-293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Streptococcus mutans is a component of the dental plaque biofilm and a major causal agent of dental caries. Log-phase cells of the organism are known to induce an acid tolerance response (ATR) at sub-lethal pH values ( approximately 5.5) that enhances survival at lower pH values such as those encountered in caries lesions. In this study, we have employed a rod biofilm chemostat system to demonstrate that, while planktonic cells induced a strong ATR at pH 5.5, biofilm cells were inherently more acid resistant than such cells in spite of a negli-gible induction of an ATR. Since these results suggested that surface growth itself triggered an ATR in biofilm cells, we were interested in comparing the effects of a pH change from 7.5 to 5.5 on protein syn-thesis by the two cell types. For this, cells were pulse labeled with [(14)C]-amino acids following the pH change to pH 5.5, the proteins extracted and separated by two-dimensional (2D) electrophoresis fol-lowed by autoradiography and computer-assisted image analysis. A comparison between the cells incubated at pH 5.5 and the control biofilm cells revealed 23 novel proteins that were absent in the control cells, and 126 proteins with an altered relative rate of synthesis. While the number of changes in protein expression in the biofilm cells was within the same range as for planktonic cells, the magnitude of their change was significantly less in biofilm cells, supporting the observa-tion that acidification of biofilm cells induced a negligible ATR. Mass spectrometry and computer-assisted protein sequence analysis revealed that ATR induction of the planktonic cells resulted in the downregula-tion of glycolytic enzymes presumably to limit cellular damage by the acidification of the external environment. On the other hand, the gly-colytic enzymes in control biofilm cells were significantly less down-regulated and key enzymes, such as lactate dehydrogenase were upregulated during pH 5.5 incubation, suggesting that the enhanced acid resistance of biofilm cells is associated with the maintenance of pH homeostasis by H+ extrusion via membrane ATPase and increased lactate efflux.

  • 25.
    Senneby, Anna
    et al.
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Davies, Julia
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Svensäter, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö högskola, Odontologiska fakulteten (OD). Malmö högskola, Biofilms Research Center for Biointerfaces.
    Acid tolerance properties of dental biofilms in vivo2017Ingår i: BMC Microbiology, E-ISSN 1471-2180, Vol. 17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The ecological plaque hypothesis explains caries development as the result of the enrichment of acid tolerant bacteria in dental biofilms in response to prolonged periods of low pH. Acid production by an acid tolerant microflora causes demineralisation of tooth enamel and thus, individuals with a greater proportion of acid tolerant bacteria would be expected to be more prone to caries development. Biofilm acid tolerance could therefore be a possible biomarker for caries prediction. However, little is known about the stability of biofilm acid tolerance over time in vivo or the distribution throughout the oral cavity. Therefore the aim of this study was to assess intra-individual differences in biofilm acid-tolerance between different tooth surfaces and inter-individual variation as well as stability of acid tolerance over time. Results: The majority of the adolescents showed low scores for biofilm acid tolerance. In 14 of 20 individuals no differences were seen between the three tooth sites examined. In the remaining six, acid-tolerance at the premolar site differed from one of the other sites. At 51 of 60 tooth sites, acid-tolerance at baseline was unchanged after 1 month. However, acid tolerance values changed over a 1-year period in 50% of the individuals. Conclusions: Biofilm acid tolerance showed short-term stability and low variation between different sites in the same individual suggesting that the acid tolerance could be a promising biological biomarker candidate for caries prediction. Further evaluation is however needed and prospective clinical trials are called for to evaluate the diagnostic accuracy.

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  • 26.
    Senneby, Anna
    et al.
    Malmö universitet, Odontologiska fakulteten (OD).
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD).
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD).
    Axtelius, Björn
    Malmö universitet, Odontologiska fakulteten (OD).
    Rohlin, Madeleine
    Malmö universitet, Odontologiska fakulteten (OD).
    Threshold values affect predictive accuracy of caries risk assessment2019Ingår i: Acta Odontologica Scandinavica, ISSN 0001-6357, E-ISSN 1502-3850, Vol. 77, nr 4, s. 315-327Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: To evaluate effects of thresholds on estimates of predictive accuracy of methods for caries risk assessment. Material and methods: Adolescents, aged 12 visiting two dental clinics, were examined by visual/tactile examination and bitewing radiography at baseline and after one year. Three methods for caries risk assessment were applied: previous caries experience, dentists’ risk assessment according to set criteria (presence or absence of caries lesion) and acid tolerance of dental biofilm. The measure for validity (the reference standard) comprised caries lesion progression at 1 year. Predictive accuracy estimates were calculated for several thresholds. Results: Accuracy estimates changed with threshold values of the methods and the reference standard. Patient spectrum differed between the clinics, which resulted in different accuracy estimates for the two samples. Generally, negative predictive values were high while positive ones were low indicating that these methods were more efficient in finding individuals who are at low risk of developing caries lesions than those with increased risk. Conclusions: As thresholds and patient spectrum affected predictive accuracy, it may be difficult to design a universal model with set thresholds for caries risk assessment. Foremost, a model should consider the level of aspiration for prediction and clinical decisions that will be made based on the risk assessment in the actual clinical setting.

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  • 27.
    Shafaat, Atefeh
    et al.
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Francisco Gonzalez-Martinez, Juan
    Polytechnic University of Cartagena: Universidad Politecnica de Cartagena, Department of Applied Physics, SPAIN.
    O Silva, Wanderson
    HES-SO Valais Wallis, Institute of system engineering, SWITZERLAND.
    Lesch, Andreas
    University of Bologna Department of Industrial Chemistry Toso Montanari: Universita degli Studi di Bologna Dipartimento di Chimica Industriale Toso Montanari, Department of Industrial Chemistry, ITALY.
    Nagar, Bhawna
    Ecole Polytechnique Federale de Lausanne, laboratory of physical and analytical electrochemistry, SWITZERLAND.
    Lopes da Silva, Zita
    Malmö universitet, Odontologiska fakulteten (OD).
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD).
    Sotres, Javier
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Björklund, Sebastian
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Girault, Hubert
    Ecole Polytechnique Federale de Lausanne, laboratory of physical and analytical electrochemistry, SWITZERLAND.
    Ruzgas, Tautgirdas
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    A Rapidly Responsive Sensor for Wireless Detection of Early and Mature Microbial Biofilms.2023Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 62, nr 40, artikel-id e202308181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biofilm-associated infections, which are able to resist antibiotics, pose a significant challenge in clinical treatments. Such infections have been linked to various medical conditions, including chronic wounds and implant-associated infections, making them a major public-health concern. Early-detection of biofilm formation offers significant advantages in mitigating adverse effects caused by biofilms. In this work, we aim to explore the feasibility of employing a novel wireless sensor for tracking both early-stage and matured-biofilms formed by the medically relevant bacteria Staphylococcus aureus and Pseudomonas aeruginosa. The sensor utilizes electrochemical reduction of an AgCl layer bridging two silver legs made by inkjet-printing, forming a part of near-field-communication tag antenna. The antenna is interfaced with a carbon cloth designed to promote the growth of microorganisms, thereby serving as an electron source for reduction of the resistive AgCl into a highly-conductive Ag bridge. The AgCl-Ag transformation significantly alters the impedance of the antenna, facilitating wireless identification of an endpoint caused by microbial growth. To the best of our knowledge, this study for the first time presents the evidence showcasing that electrons released through the actions of bacteria can be harnessed to convert AgCl to Ag, thus enabling the wireless, battery-less, and chip-less early-detection of biofilm formation.

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  • 28.
    Shafaat, Atefeh
    et al.
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö 205 06, Sweden;Biofilms−Research Center for Biointerfaces, Malmö University, Malmö 205 06, Sweden.
    Žalnėravičius, Rokas
    State Research Institute, Centre for Physical Sciences and Technology, Saulėtekio av. 3, Vilnius LT-10257, Lithuania.
    Ratautas, Dalius
    Institute of Biochemistry, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, Vilnius LT-10223, Lithuania;Faculty of Fundamental Sciences, Vilnius Gediminas Technical University, Saulėtekio al. 11, Vilnius LT-10223, Lithuania.
    Dagys, Marius
    Institute of Biochemistry, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, Vilnius LT-10223, Lithuania.
    Meškys, Rolandas
    Institute of Biochemistry, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, Vilnius LT-10223, Lithuania.
    Rutkienė, Rasa
    Institute of Biochemistry, Life Sciences Centre, Vilnius University, Saulėtekio al. 7, Vilnius LT-10223, Lithuania.
    Gonzalez-Martinez, Juan Francisco
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Björklund, Sebastian
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Sotres, Javier
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Ruzgas, Tautgirdas
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Department of Biomedical Science, Faculty of Health and Society, Malmö University, Malmö 205 06, Sweden;Biofilms−Research Center for Biointerfaces, Malmö University, Malmö 205 06, Sweden.
    Glucose-to-Resistor Transduction Integrated into a Radio-Frequency Antenna for Chip-less and Battery-less Wireless Sensing2022Ingår i: ACS Sensors, E-ISSN 2379-3694, Vol. 7, nr 4, s. 1222-1234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To maximize the potential of 5G infrastructure in healthcare, simple integration of biosensors with wireless tag antennas would be beneficial. This work introduces novel glucose-to-resistor transduction, which enables simple, wireless biosensor design. The biosensor was realized on a near-field communication tag antenna, where a sensing bioanode generated electrical current and electroreduced a nonconducting antenna material into an excellent conductor. For this, a part of the antenna was replaced by a Ag nanoparticle layer oxidized to high-resistance AgCl. The bioanode was based on Au nanoparticle-wired glucose dehydrogenase (GDH). The exposure of the cathode-bioanode to glucose solution resulted in GDH-catalyzed oxidation of glucose at the bioanode with a concomitant reduction of AgCl to highly conducting Ag on the cathode. The AgCl-to-Ag conversion strongly affected the impedance of the antenna circuit, allowing wireless detection of glucose. Mimicking the final application, the proposed wireless biosensor was ultimately evaluated through the measurement of glucose in whole blood, showing good agreement with the values obtained with a commercially available glucometer. This work, for the first time, demonstrates that making a part of the antenna from the AgCl layer allows achieving simple, chip-less, and battery-less wireless sensing of enzyme-catalyzed reduction reaction. 

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  • 29.
    Svensäter, Gunnel
    et al.
    Malmö högskola, Odontologiska fakulteten (OD).
    Davies, Julia
    Malmö högskola, Odontologiska fakulteten (OD).
    Hänsel Petersson, Gunnel
    Malmö högskola, Odontologiska fakulteten (OD).
    Knutsson, Kerstin
    Malmö högskola, Odontologiska fakulteten (OD).
    Neilands, Jessica
    Malmö högskola, Odontologiska fakulteten (OD).
    Rohlin, Madeleine
    Malmö högskola, Odontologiska fakulteten (OD).
    Mejàre, Ingegerd
    Malmö högskola, Odontologiska fakulteten (OD).
    Petersson, Lars G
    Sahlin, Nils-Eeic
    Carlén, Annette
    Dahlén, Gunnar
    Risk, riskbedömning och prevention2008Ingår i: Tandläkartidningen, ISSN 0039-6982, Vol. 100, nr 9-10, s. 70-76Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Biologiska markörer som baserar sig på egenskaper och aktivitet hos bakterier i dentala biofilmer skulle kunna användas för att identifiera patienter med hög risk för karies och parodontit. Genom att studera hur tandläkare gör riskbedömningar och tar beslut om åtgärder kan man få ett bra underlag för att förbättra praxis.

  • 30.
    Svärd, Anna
    et al.
    Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83, Sweden; Cardiovascular Research Centre (CVRC), School of Medical Sciences, Örebro University, Örebro, 70182, Sweden.
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Palm, Eleonor
    Cardiovascular Research Centre (CVRC), School of Medical Sciences, Örebro University, Örebro, 70182, Sweden.
    Svensäter, Gunnel
    Malmö universitet, Odontologiska fakulteten (OD). Malmö universitet, Biofilms Research Center for Biointerfaces.
    Bengtsson, Torbjorn
    Cardiovascular Research Centre (CVRC), School of Medical Sciences, Örebro University, Örebro, 70182, Sweden.
    Aili, Daniel
    Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83, Sweden.
    Protein-Functionalized Gold Nanoparticles as Refractometric Nanoplasmonic Sensors for the Detection of Proteolytic Activity of Porphyromonas gingivalis2020Ingår i: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 3, nr 10, s. 9822-9830Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Periodontitis is an inflammatory oral disease that affects a large part of the adult population, causing significant costs and suffering. The key pathogen, Porphyromonas gingivalis, secretes gingipains, which are highly destructive proteases and the most important virulence factors in the pathogenesis of the disease. Currently, periodontitis is diagnosed mainly by mechanical manual probing and radiography, often when the disease has already progressed significantly. The possibilities of detecting gingipain activity in gingival fluid could enable early-stage diagnosis and facilitate treatment. Here, we describe a sensitive nanoparticle-based nanoplasmonic biosensor for the detection of the proteolytic activity of gingipains. Gold nanoparticles (AuNPs) were self-assembled as a submonolayer in multiwell plates and further modified with casein or IgG. The proteolytic degradation of the protein coating was tracked by monitoring the shift in the localized surface plasmon resonance (LSPR) peak position. The sensor performance was investigated using model systems with trypsin and purified gingipains (subtypes Kgp and RgpB) and further validated using supernatants from cultures of P. gingivalis. Proteolytic degradation by proteases in buffer results in a concentration- and time-dependent blueshift of the LSPR band of about 1-2 nm when using casein as a substrate. In bacterial supernatants, the degradation of the protein coating resulted in unspecific binding of proteins present in the complex sample matrix to the nanoparticles, which instead triggered a redshift of about 2 nm of the LSPR band. A significant LSPR shift was seen only in samples with gingipain activity. The sensor showed a limit of detection < 0.1 mu g/mL (4.3 nM), which is well below gingipain concentrations detected in severe chronic periodontitis cases (similar to 50 mu g/mL). This work shows the possibility of developing cost-effective nanoparticle-based biosensors for rapid detection of protease activity for chair-side periodontal diagnostics.

  • 31.
    Thirabowonkitphithan, Pannawich
    et al.
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces. Graduate Program in Clinical Biochemistry and Molecular Medicine, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand.
    Žalnėravičius, Rokas
    Center for Physical Sciences and Technology, Department of Electrochemical Material Science, Sauletekio av. 3, LT-10257, Vilnius, Lithuania; Institute of Biochemistry, Life Sciences Centre, Vilnius University, Sauletekio av. 7, LT-10257, Vilnius, Lithuania.
    Shafaat, Atefeh
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Jakubauskas, Dainius
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Neilands, Jessica
    Malmö universitet, Odontologiska fakulteten (OD).
    Laiwattanapaisal, Wanida
    Centre of Excellence for Biosensors and Bioengineering (CEBB), Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, 10330, Thailand; Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand.
    Ruzgas, Tautgirdas
    Malmö universitet, Biofilms Research Center for Biointerfaces. Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV).
    Electrogenicity of microbial biofilms of medically relevant microorganisms: potentiometric, amperometric and wireless detection.2024Ingår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 246, artikel-id 115892Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since the progression of biofilm formation is related to the success of infection treatment, detecting microbial biofilms is of great interest. Biofilms of Gram-positive Staphylococcus aureus and Streptococcus gordonii bacteria, Gram-negative Pseudomonas aeruginosa and Escherichia coli bacteria, and Candida albicans yeast were examined using potentiometric, amperometric, and wireless readout modes in this study. As a biofilm formed, the open circuit potential (OCP) of biofilm hosting electrode (bioanode) became increasingly negative. Depending on the microorganism, the OCP ranged from −70 to −250 mV. The co-culture generated the most negative OCP (−300 mV vs Ag/AgCl), while the single-species biofilm formed by E. coli developed the least negative (−70 mV). The OCP of a fungal biofilm formed by C. albicans was −100 mV. The difference in electrode currents generated by biofilms was more pronounced. The current density of the S. aureus biofilm was 0.9‧10−7 A cm−2, while the value of the P. aeruginosa biofilm was 1.3‧10−6 A cm−2. Importantly, a biofilm formed by a co-culture of S. aureus and P. aeruginosa had a slightly higher negative OCP value and current density than the most electrogenic P. aeruginosa single-species biofilm. We present evidence that bacteria can share redox mediators found in multi-species biofilms. This synergy, enabling higher current and OCP values of multi-species biofilm hosting electrodes, could be beneficial for electrochemical detection of infectious biofilms in clinics. We demonstrate that the electrogenic biofilm can provide basis to construct novel wireless, chip-free, and battery-free biofilm detection method.

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