Biofilm最新文献

{"title":"Transcatheter aortic valve implantation (TAVI) prostheses in vitro - biofilm formation and antibiotic effects","authors":"","doi":"10.1016/j.bioflm.2024.100236","DOIUrl":"10.1016/j.bioflm.2024.100236","url":null,"abstract":"<div><h3>Background</h3><div>Transcatheter aortic valve implantation (TAVI) is a percutaneous catheter-based treatment of aortic stenosis as an alternative to open heart valve surgery. In cases of TAVI endocarditis, the treatment possibilities may be limited as surgical removal of the infected valve may be associated with a high risk in elderly, comorbid or frail patients. The propensity of bacteria to form a biofilm on foreign material is assumed to be of importance part of the disease process in TAVI endocarditis, but no studies on biofilm formation on TAVI valves have been conducted. We hypothesize that <em>Staphylococcus aureus</em> and <em>Enterococcus faecalis</em> biofilm formation on TAVI valves may have an impact on antibiotic tolerance and non-surgical cure rates.</div></div><div><h3>Methods</h3><div>TAVI valves (pieces including part of the metal frame, approximately 1 cm wide) were exposed to either species <em>in vitro</em> in LB-Krebs Ringer medium at 37 °C, with the bacterial count being assessed by culturing of sonicated TAVI pieces and broth at 0, 4, 18 and 24 h after bacterial exposure. Scanning electron microscopy (SEM) was performed. Effects of ampicillin, gentamicin, moxifloxacin, rifampicin (for <em>S. aureus</em>), and ceftriaxone (for <em>E. faecalis</em>) at 5 times minimal inhibitory concentration were tested alone and in combination with ampicillin. Antibiotics were added to biofilm aged 0 or 24 h and the effects assessed.</div></div><div><h3>Results</h3><div>Exposure for 15 min established attachment to all of valve pieces. SEM findings were consistent with biofilm formation and suggested lower amounts of bacteria on the metal compared to the tissue part of the TAVI valves. The number of bacteria attached to the TAVI valves increased until 24 h of incubation from less than 10^1 to a level of approximately 10^9 CFU/g. The bacteria became more tolerant to antibiotics on the TAVI valves over time, with the bactericidal effect against 24-h old biofilm being significantly less effective than against 0-h old biofilm depending on antibiotic.</div></div><div><h3>Conclusions</h3><div>The results indicate that bacteria can adhere to metal and tissue parts of the TAVI valves within minutes after an exposure which is comparable to transient bacteremia <em>in vivo</em>, and that the bacteria rapidly gain biofilm properties, associated with significantly reduced antibiotic effect.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of nanoparticles on anaerobic, anammox, aerobic, and algal-bacterial granular sludge: A comprehensive review","authors":"","doi":"10.1016/j.bioflm.2024.100234","DOIUrl":"10.1016/j.bioflm.2024.100234","url":null,"abstract":"<div><div>Nanoparticles (NPs) are of significant interest due to their unique properties, such as large surface area and high reactivity, which have facilitated advancements in various fields. However, their increased use raises concerns about environmental impacts, including on wastewater treatment processes. This review examines the effects of different nanoparticles on anaerobic, anammox, aerobic, and algal-bacterial granular sludge used in wastewater treatment. CeO₂ and Ag NPs demonstrated adverse effects on aerobic granular sludge (AGS), reducing nutrient removal and cellular function, while anaerobic granular sludge (AnGS) and anammox granular sludge (AxGS) showed greater resilience due to their higher extracellular polymeric substance (EPS) content. TiO₂ NPs had fewer negative effects on algal-bacterial granular sludge (ABGS) than on AGS, as algae played a crucial role in enhancing EPS production and stabilizing the granules. The addition of Fe₃O₄ NPs significantly enhanced both aerobic and anammox granulation by reducing granulation time, promoting microbial interactions, improving granule stability, and increasing nitrogen removal efficiency, primarily through increased EPS production and enzyme activity. However, Cu and CuO NPs exhibited strong inhibitory effects on aerobic, anammox, and anaerobic systems, affecting EPS structure, cellular integrity, and microbial viability. ZnO NPs demonstrated dose-dependent toxicity, with higher concentrations inducing oxidative stress and reducing performance in AGS and AnGS, whereas AxGS and ABGS were more tolerant due to enhanced EPS production and algae-mediated protection. The existing knowledge gaps and directions for future research on NPs are identified and discussed.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and comparison of protein composition of biofilms in response to EGCG from Enterococcus faecalis and Staphylococcus lugdunensis, which showed opposite patterns in biofilm-forming abilities","authors":"","doi":"10.1016/j.bioflm.2024.100232","DOIUrl":"10.1016/j.bioflm.2024.100232","url":null,"abstract":"<div><div>Bacterial biofilm is resistant to conventional antibiotic treatments, leading to complications associated with many infection-related human diseases. Epigallocatechin Gallate (EGCG), a phenolic catechin enriched in green tea, is recognized for its anti-bacterial and anti-biofilm activities. In this study, we examined the protein components of the biofilms formed in the absence or presence of EGCG using <em>Enterococcus faecalis</em> and <em>Staphylococcus lugdunensis,</em> which had shown opposing patterns in biofilm formation. A clustering heatmap revealed that the two microorganisms expressed the different protein sets in response to EGCG. Proteins that were noticeably upregulated included those associated with stress responsiveness and gluconeogenesis in <em>E. faecalis</em>, and gene modification in <em>S. lugdunensis</em>. Conversely, downregulated proteins were related to tRNA-modifying enzyme activity in <em>E. faecalis</em>, and anabolic metabolism in <em>S. lugdunensis</em>. Among the proteins identified only in EGCG-responsive biofilms, enzymes involved in de novo purine biosynthesis were enriched in <em>E. faecalis</em>, while proteins likely to cause DNA instability and pathogenicity changes were abundantly present in <em>S. lugdunensis</em>. The classification based on gene ontology (GO) terms by microorganism exhibited that metabolic process or catabolic activity was at the top rank in <em>E. faecalis</em> with more than 33 proteins, and in <em>S. lugdunensis</em>, localization or transport was highly ranked with 4 proteins. These results support the hypothesis that EGCG might cause different cellular programs in each microorganism. Finally, comparison of the proteomes between two groups that form biofilms to similar extents discovered that 2 proteins were commonly found in the weak biofilm-forming groups (<em>E. faecalis</em> and EGCG-responding <em>S. lugudunensis</em>), whereas 9 proteins were common among the strong biofilm-forming groups (<em>S. lugdunensis</em> and EGCG-responding <em>E. faecalis</em>). It was suggested that these proteins could serve as potential indicators to detect the presence and predict the extent of biofilm formation by multiple microorganisms. Taken all together, proteomics data and analyses performed in this study provided useful and new information on the proteins embedded in the biofilms formed at the specific conditions, which can aid in diagnosis and the development of tailored treatment strategies.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cooperation between coagulase and von willebrand factor binding protein in Staphylococcus aureus fibrin pseudocapsule formation","authors":"","doi":"10.1016/j.bioflm.2024.100233","DOIUrl":"10.1016/j.bioflm.2024.100233","url":null,"abstract":"<div><div>The major human pathogen <em>Staphylococcus aureus</em> forms biofilms comprising of a fibrin network that increases attachment to surfaces and shields bacteria from the immune system. It secretes two coagulases, Coagulase (Coa) and von Willebrand factor binding protein (vWbp), which hijack the host coagulation cascade and trigger the formation of this fibrin clot. However, it is unclear how Coa and vWbp contribute differently to the localisation and dynamics of clot assembly in growing biofilms.</div><div>Here, we address this question using high-precision time-resolved confocal microscopy of fluorescent fibrin to establish the spatiotemporal dynamics of fibrin clot formation in functional biofilms. We also use fluorescent fusion proteins to visualise the locations of Coa and vWbp in biofilms using both confocal laser scanning and high resolution highly inclined and laminated optical sheet microscopy. We visualise and quantify the spatiotemporal dynamics of fibrin production during initiation of biofilms in plasma amended with fluorescently labelled fibrinogen.</div><div>We find that human serum stimulates coagulase production, and that Coa and vWbp loosely associate to the bacterial cell surface. Coa localises to cell surfaces to produce a surface-attached fibrin pseudocapsule but can diffuse from cells to produce matrix-associated fibrin. vWbp produces matrix-associated fibrin in the absence of Coa, and furthermore accelerates pseudocapsule production when Coa is present. Finally, we observe that fibrin production varies across the biofilm. A sub-population of non-dividing cells does not produce any pseudocapsule but remains within the protective extended fibrin network, which could be important for the persistence of <em>S. aureus</em> biofilm infections as antibiotics are more effective against actively growing cells.</div><div>Our findings indicate a more cooperative role between Coa and vWbp in building fibrin networks than previously thought, and a bet-hedging cell strategy where some cells produce biofilm matrix while others do not, but instead assume a dormant phenotype that could be associated with antibiotic tolerance.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collateral susceptibility-guided alternation of ceftolozane/tazobactam with imipenem prevents resistance development in XDR Pseudomonas aeruginosa biofilms","authors":"","doi":"10.1016/j.bioflm.2024.100231","DOIUrl":"10.1016/j.bioflm.2024.100231","url":null,"abstract":"<div><h3>Objectives</h3><div>New combinations of β-lactams and β-lactamase inhibitors, such as ceftolozane/tazobactam could be useful to combat biofilm-driven chronic infections by extensively resistant (XDR) <em>Pseudomonas aeruginosa</em> but resistance development by mutations in the Ω-loop of AmpC has been described. However, these mutations confer collateral susceptibility to carbapenems. Thus we aimed to evaluate the therapeutic efficacy and the prevention of resistance development of regimen alternating ceftolozane/tazobactam and imipenem.</div></div><div><h3>Methods</h3><div>A carbapenem-resistant XDR <em>P. aeruginosa</em> clinical strain (ST175, 104-B7) and its isogenic imipenem-susceptible ceftolozane/tazobactam-resistant mutant derivative (AmpC T96I, 104-I9) were used. Experiments of single strains and mixed (104-B7 and 104-I9, 1:0.01 ratio) biofilms were performed. 48h biofilms (flow cell system) were treated for 6 days with either ceftolozane/tazobactam, 4/4 mg/L or the alternation of ceftolozane/tazobactam (2 days)-imipenem 4 mg/L (2 days) - ceftolozane/tazobactam (2 days). After treatment, biofilms were collected and plated on Mueller-Hinton agar± ceftolozane/tazobactam 4/4 mg/L. Structural dynamics were monitored using confocal laser scanning microscopy and images were processed with IMARIS software. At least, three independent triplicate experiments per condition were performed. Emerging resistant mutants were characterized through whole genome sequencing (Illumina).</div></div><div><h3>Results</h3><div>Ceftolozane/tazobactam monotherapy failed to reduce the biofilms of the 104-B7 XDR strain and led to the selection of resistant mutants that showed AmpC Ω-loop mutations (T96I, L244R or aa236Δ7). On the contrary, alternation with imipenem enhanced activity (3 Logs reduction at day 6) and prevented the emergence of ceftolozane/tazobactam-resistant mutants. Likewise, treatment with ceftolozane/tazobactam dramatically amplified the resistant strain 104-I9 in mixed biofilms (&gt;90 % of the population), while the alternation regimen counterselected it.</div></div><div><h3>Conclusions</h3><div>Collateral susceptibility-guided alternation of ceftolozane/tazobactam with imipenem effectively prevented the selection of resistant mutants and thus could be a potential therapeutic strategy for the treatment of <em>P. aeruginosa</em> XDR chronic infections.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma activated water pre-treatment substantially enhances phage activity against Proteus mirabilis biofilms","authors":"","doi":"10.1016/j.bioflm.2024.100230","DOIUrl":"10.1016/j.bioflm.2024.100230","url":null,"abstract":"<div><div>The ongoing antimicrobial resistance crisis has incentivised research into alternative antibacterial and antibiofilm agents. One of them is plasma-activated water (PAW), which is produced by exposing water to a cold plasma discharge. This process generates a diverse array of reactive oxygen and nitrogen species (ROS/RNS) with antimicrobial properties. Another intensively studied class of alternative antimicrobials are bacteriophages, attracting attention due to their specificity and strong antibacterial activity. As combinations of different types of antimicrobials are known to often exhibit synergistic interactions, in this study we investigated the combined use of cold atmospheric-pressure plasma-activated water and the bacteriophage vB_PmiS_PM-CJR against <em>Proteus mirabilis</em> biofilms as a potential option for treatment of catheter-associated urinary tract infections (CAUTIs).</div><div>We compared the effect of two cold plasma discharge setups for PAW production on its antimicrobial efficacy against <em>P. mirabilis</em> planktonic and biofilm cultures. Next, we assessed the stability of the phage vB_PmiS_PM-CJR in PAW. Finally, we tested the antimicrobial activity of the phages and PAW against biofilms, both individually and in combinations.</div><div>Our findings demonstrate that the combination of PAW with phage is more effective against biofilms compared to individual treatments, being able to reduce the number of biofilm-embedded cells by approximately 4 log. We were also able to show that the order of treatment plays an important role in the anti-biofilm activity of the phage-PAW combination, as the exposure of the biofilm to PAW prior to phage administration results in a stronger effect than the reverse order.</div><div>This research underlines PAW's ability to potentiate phage activity, showcasing a considerable reduction in biofilm viability and biomass. Additionally, it contributes to the growing body of evidence supporting the use of phage-based combinatorial treatments. Overall, this sequential treatment strategy demonstrates the potential of leveraging multiple approaches to address the mounting challenge of antibiotic resistance and offers a promising avenue for enhancing the efficacy of CAUTI management.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear viscoelasticity of filamentous fungal biofilms of Neurospora discreta","authors":"","doi":"10.1016/j.bioflm.2024.100227","DOIUrl":"10.1016/j.bioflm.2024.100227","url":null,"abstract":"<div><div>The picture of bacterial biofilms as a colloidal gel composed of rigid bacterial cells protected by extracellular crosslinked polymer matrix has been pivotal in understanding their ability to adapt their microstructure and viscoelasticity to environmental assaults. This work explores if an analogous perspective exists in fungal biofilms with long filamentous cells. To this end, we consider biofilms of the fungus <em>Neurospora discreta</em> formed on the air-liquid interface, which has shown an ability to remove excess nitrogen and phosphorous from wastewater effectively. We investigated the changes to the viscoelasticity and the microstructure of these biofilms when the biofilms uptake varying concentrations of nitrogen and phosphorous, using large amplitude oscillatory shear flow rheology (LAOS) and field-emission scanning electron microscopy (FESEM), respectively. A distinctive peak in the loss modulus (G″) at 30–50 % shear strain is observed, indicating the transition from an elastic to plastic deformation state. Though a peak in G″ has been observed in several soft materials, including bacterial biofilms, it has eluded interpretation in terms of quantifiable microstructural features. The central finding of this work is that the intensity of the G″ peak, signifying resistance to large deformations, correlates directly with the protein and polysaccharide concentrations per unit biomass in the extracellular matrix and inversely with the shear-induced changes in filament orientation in the hyphal network. These correlations have implications for the rational design of fungal biofilms with tuneable mechanical properties.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biofilm morphology and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) on poly-D,L-lactide-co-poly(ethylene glycol) (PDLLA-PEG) coated titanium","authors":"","doi":"10.1016/j.bioflm.2024.100228","DOIUrl":"10.1016/j.bioflm.2024.100228","url":null,"abstract":"<div><div>Biodegradable polymeric coatings are being explored as a preventive strategy for orthopaedic device-related infection. In this study, titanium surfaces (Ti) were coated with poly-D,L-lactide (PDLLA, (P)), polyethylene-glycol poly-D,L-lactide <strong>(</strong>PEGylated-PDLLA, (PP20)), or multi-layered PEGylated-PDLLA (M), with or without 1 % silver sulfadiazine. The aim was to evaluate their cytocompatibility, resistance to <em>Staphylococcus aureus</em> biofilm formation, and their potential to enhance the susceptibility of any biofilm formed to antibiotics. Using automated high-content screening confocal microscopy, biofilm formation of a clinical methicillin-resistant <em>Staphylococcus aureus</em> (MRSA) isolate expressing GFP was quantified, along with isogenic mutants that were unable to form polysaccharidic or proteinaceous biofilm matrices. The results showed that PEGylated-PDLLA coatings exhibited significant antibiofilm properties, with M showing the highest effect. This inhibitory effect was stronger in <em>S. aureus</em> biofilms with a matrix composed of proteins compared to those with an exopolysaccharide (PIA) biofilm matrix. Our data suggest that the antibiofilm effect may have been due to (i) inhibition of the initial attachment through microbial surface components recognising adhesive matrix molecules (MSCRAMMs), since PEG reduces protein surface adsorption via surface hydration layer and steric repulsion; and (ii) mechanical disaggregation and dispersal of microcolonies due to the bioresorbable/degradable nature of the polymers, which undergo hydration and hydrolysis over time. The disruption of biofilm morphology by the PDLLA-PEG co-polymers increased <em>S. aureus</em> susceptibility to antibiotics like rifampicin and fusidic acid. Adding 1 % AgSD provided additional early bactericidal effects on both biofilm and planktonic <em>S. aureus</em>. Additionally, the coatings were cytocompatible with immune cells, indicating their potential to enhance bacterial clearance and reduce bacterial colonisation of titanium-based orthopaedic biomaterials.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large-scale screening identifies enzyme combinations that remove in situ grown oral biofilm","authors":"","doi":"10.1016/j.bioflm.2024.100229","DOIUrl":"10.1016/j.bioflm.2024.100229","url":null,"abstract":"<div><div>Bacteria in the oral cavity are responsible for the development of dental diseases such as caries and periodontitis, but it is becoming increasingly clear that the oral microbiome also benefits human health. Many oral care products on the market are antimicrobial, killing a large part of the oral microbiome but without removing the disease-causing biofilm. Instead, non-biocidal matrix-degrading enzymes may be used to selectively remove biofilm without harming the overall microbiome.</div><div>The challenge of using enzymes to degrade biofilms is to match the narrow specificity of enzymes with the large structural diversity of extracellular polymeric substances that hold the biofilm together. In this study, we therefore perform a large-scale screening of single and multi-enzyme formulations to identify combinations of enzymes that most effectively remove dental biofilm.</div><div>We tested &gt;400 different treatment modalities using 44 different enzymes in combinations with up to six enzymes in each formulation, on <em>in vitro</em> biofilms inoculated with human saliva. Mutanase was the only enzyme capable of removing biofilm on its own. Multi-enzyme formulations removed up to 69 % of the biofilm volume, and the most effective formulations all contained mutanase. We shortlisted 10 enzyme formulations to investigate their efficacy against biofilms formed on glass slabs on dental splints worn by 9 different test subjects. Three of the ten formulations removed more than 50 % of the biofilm volume. If optimal enzyme concentration and exposure time can be reached <em>in vivo</em>, these enzyme combinations have potential to be used in novel non-biocidal oral care products for dental biofilm control.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic, conductive nanoparticles as building blocks for steerable micropillar-structured anodic biofilms","authors":"","doi":"10.1016/j.bioflm.2024.100226","DOIUrl":"10.1016/j.bioflm.2024.100226","url":null,"abstract":"<div><div>In bioelectrochemical systems (BES), biofilm formation and architecture are of crucial importance, especially for flow-through applications. The interface between electroactive microorganisms and the electrode surface plays an important and often limiting role, as the available surface area influences current generation, especially for poor biofilm forming organisms. To overcome the limitation of the available electrode surface, nanoparticles (NPs) with a magnetic iron core and a conductive, hydrophobic carbon shell were used as building blocks to form conductive, magnetic micropillars on the anode surface. The formation of this dynamic three-dimensional electrode architecture was monitored and quantified <em>in situ</em> using optical coherence tomography (OCT) in conjunction with microfluidic BES systems. By cyclic voltammetry the assembled three-dimensional anode extensions were found to be electrically conductive and increased the available electroactive surface area. The NPs were used as controllable carriers for the electroactive model organisms <em>Shewanella oneidensis</em> and <em>Geobacter sulfurreducens</em>, resulting in a 5-fold increase in steady-state current density for <em>S. oneidensis</em>, which could be increased 22-fold when combined with Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) aggregates. In the case of <em>G. sulfurreducens</em>, the steady-state current density was not increased, but was achieved four times faster. The study presents a controllable, scalable and easy-to-use method to increase the electrode surface area in existing BES by applying a magnetic field and adding conductive magnetic NPs. These findings can most likely also be transferred to other electroactive microorganisms.</div></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}