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The bioelectrochemical conversion of CO2 to CH4 (electromethanogenesis), using renewable energy, is a promising power-to-gas technology. However, maximizing its potential requires the development of cost-effective materials for biocathodes. A recent research achieved significant progress by employing a ternary composite material comprising porous carbon (biochar) modified with 20 wt% copper and 10 wt% hydroxyapatite (HAP). Notably, the addition of HAP led to a remarkable increase in methane production compared to undoped biochar and Cu-doped biochar, reaching a maximum of 0.87 mol m−2 d−1 with a coulombic efficiency of 64%. Based on these results, this study aims to elucidate the pivotal role of hydroxyapatite as a crucial modifier in biochar-based cathode materials. Employing a range of characterization techniques such as N2 adsorption/desorption isotherms, solid–liquid phase titrations with probe molecules, electron microscopy, and infrared spectroscopy, the research delved into the unique contributions of hydroxyapatite surface features to the electromethanogenesis process on the composite cathode. The results underscored the beneficial effects of HAP in enhancing reagent adsorption, providing a hydrophilic interface beneficial to microbial adhesion, and stabilizing the interface pH. This comprehensive investigation sheds light on the factors underlying the enhanced performance of bioelectrochemical systems facilitated by HAP-modified cathode materials. [ABSTRACT FROM AUTHOR]

Objectives. This in vitro study aimed to develop a novel nanocomposite acrylic resin with inherent antimicrobial properties. This study evaluated its effectiveness against microbial biofilm formation, while also assessing its physical and mechanical properties. Methods. Polymethylmethacrylate (PMMA) was modified with four different concentrations of chlorhexidine halloysite nanotubes (CHX-HNTs): 1%, 1.5%, 3%, and 4.5 wt.% by weight, along with a control group (0 wt.% CHX-HNTs). The biofilm inhibition ability of the modified CHX-HNTs acrylic against Candida albicans, Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus agalactiae was assessed using microtiter biofilm test. In addition, ten samples from each group were then tested for flexural strength, surface roughness, and hardness. Statistical analysis was performed using one-way ANOVA and Tukey's test for comparison (P < 0.05). Results. CHX-HNTs effectively reduced the adhesion of Candida albicans and bacteria to the PMMA in a dose-dependent manner. The higher the concentration of CHX-HNTs, the greater the reduction in microbial adhesion, with the highest concentration (4.5 wt.%) showing the most significant effect with inhibition rates ≥98%. The addition of CHX-HNTs at any tested concentration (1%, 1.5%, 3%, and 4.5 wt.%) did not cause any statistically significant difference in the flexural strength, surface roughness, or hardness of the PMMA compared to the control group. Conclusions. The novel integration of CHX-HNT fillers shows promising results as an effective biofilm inhibitor on acrylic appliances. This new approach has the potential to successfully control infectious diseases without negatively affecting the mechanical properties of the acrylic resin. Clinical Relevance. The integration of CHX-HNTs into presurgical infant orthopedic appliances should be thoroughly assessed as a promising preventive measure to mitigate microbial infections. This evaluation holds significant potential for controlling infectious diseases among infants with cleft lip and palate, thereby offering a valuable contribution to their overall well-being. [ABSTRACT FROM AUTHOR]

Urban tailwater typically has a low carbon-to-nitrogen ratio and adding external carbon sources can effectively improve the denitrification performance of wastewater. However, it is difficult to determine the dosage of additional carbon sources, leading to insufficient or excessive addition. Therefore, it is necessary to prepare solid slow-release carbon source (SRC) materials to solve the difficulty in determining the dosage of carbon sources. This study selected two SRCs of slow-release carbon source 1 (SRC1) and slow-release carbon source 2 (SRC2), with good slow-release performance after static carbon release and batch experiments. The composition of SRC1 was: hydroxypropyl methylcellulose/disodium fumarate/polyhydroxy alkanoate (HPMC/DF/PHA) at a ratio of 3:2:4, with an Fe3O4 mass fraction of 3%. The composition of SRC2 was: HPMC/DF/PHA with a ratio of 1:1:1 and an Fe3O4 mass fraction of 3%. The fitted equations of carbon release curves of SRC1 and SRC2 were y = 61.91 + 7190.24e−0.37t and y = 47.92 + 8770.42e−0.43t, respectively. The surfaces of SRC1 and SRC2 had a loose and porous morphological structure, which could increase the specific surface area of materials and be more conducive to the adhesion and metabolism of microorganisms. The experimental nitrogen removal by denitrification with SRCs showed that when the initial total nitrogen concentration was 40.00 mg/L, the nitrate nitrogen (NO3−-N) concentrations of the SRC1 and SRC2 groups on the 10th day were 2.57 and 2.66 mg/L, respectively. On the 20th day, the NO3−-N concentrations of the SRC1 and SRC2 groups were 1.67 and 2.16 mg/L, respectively, corresponding to removal efficiencies of 95.83% and 94.60%, respectively. The experimental results indicated that SRCs had a good nitrogen removal effect. Developing these kinds of materials can provide a feasible way to overcome the difficulty in determining the dosage of carbon sources in the process of heterotrophic denitrification. [ABSTRACT FROM AUTHOR]

Our study aimed to identify markers of enterococci's virulence potential by evaluating the properties of strains of different sites of isolation. Enterococcal strains were isolated as commensals from faeces and as invasive strains from the urine and blood of patients from the University Clinical Centre, Gdańsk, Poland. Changes in monocytes' susceptibility to the cytotoxic activity of isolates of different origins and their adherence to biofilm were evaluated using a flow cytometer. The bacterial protein profile was estimated by matrix assisted laser desorption ionization-time of flight mass spectrometer. The cytotoxicity of biofilm and monocytes' adherence to it were the most accurate factors in predicting the prevalence of the strain in the specific niche. Additionally, a bacterial protein with mass-to-charge ratio (m / z) 5000 was found to be responsible for the increased bacterial cytotoxicity, while monocytes' decreased adherence to biofilm was linked with the presence of proteins either with m / z 3330 or 2435. The results illustrate that monocytes' reaction when exposed to the bacterial biofilm can be used as an estimator of pathogens' virulence potential. The observed differences in monocytes' response are explainable by the bacterial proteins' profile. Additionally, the results indicate that the features of both bacteria and monocytes impact the outcome of the infection. [ABSTRACT FROM AUTHOR]

Biofilms inhabit a range of environments, such as dental plaques or soil micropores, often characterized by noneven surfaces. However, the impact of surface irregularities on the population dynamics of biofilms remains elusive, as most experiments are conducted on flat surfaces. Here, we show that the shape of the surface on which a biofilm grows influences genetic drift and selection within the biofilm. We culture Escherichia coli biofilms in microwells with a corrugated bottom surface and observe the emergence of clonal sectors whose size corresponds to that of the corrugations, despite no physical barrier separating different areas of the biofilm. The sectors are remarkably stable and do not invade each other; we attribute this stability to the characteristics of the velocity field within the biofilm, which hinders mixing and clonal expansion. A microscopically detailed computer model fully reproduces these findings and highlights the role of mechanical interactions such as adhesion and friction in microbial evolution. The model also predicts clonal expansion to be limited even for clones with a significant growth advantage--a finding which we confirm experimentally using a mixture of antibiotic-sensitive and antibiotic-resistant mutants in the presence of sublethal concentrations of the antibiotic rifampicin. The strong suppression of selection contrasts sharply with the behavior seen in range expansion experiments in bacterial colonies grown on agar. Our results show that biofilm population dynamics can be affected by patterning the surface and demonstrate how a better understanding of the physics of bacterial growth can be used to control microbial evolution. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to investigate microorganism adhesion and biofilm formation between pure and ceramic-reinforced polyetheretherketone (PEEK) materials. Methods: A total of 72 rectangular (8 x 8 x 4 mm) samples were prepared from pure-PEEK without filler and PEEK (Ceramicreinforced PEEK - bio high-performance polymer) containing 20% nano-ceramic filler. A profilometer contact surface measurement device was used to assess the surface roughness of the samples. PEEK groups (36 pure PEEK, 36 Ceramic-reinforced PEEK) were divided into 4 sub-groups of 9 according to the microorganism strains. Staphylococcus aureus [American Type Culture Collection (ATCC 29213)], Acinetobacter baumannii (ATCC 19606), Enterococcus faecalis (ATCC 29212), and Candida albicans (ATCC 10231) standard strains were used for microbiological analysis. Blocks were added to 24-well microplates containing suspensions of microorganisms and were incubated at 37 °C for 72 hours. Microplates were read at a wavelength of 490 nm using crystal violet. Results: No significant difference was determined between the PEEK groups in terms of surface roughness. No significant differences in biofilm formation of S. aureus, A. baummanii, E. faecalis, and C. albicans strains were found between the PEEK groups (p>0.05). In the pure-PEEK, the highest adhesion was recorded in S. aureus (p<0.001), and the lowest adhesion in C. albicans (p<0.001). In the ceramic-reinforced PEEK group, S. aureus and A. baummanii adhesions were observed more than E. faecalis and C. Albicans (p<0.001). Conclusion: The results of this investigation demonstrated no significant differences in the biofilm formation of different strains between PEEK materials. This was a preliminary study to define the biological characteristics of ceramic-reinforced PEEK. There is a need for further comparative and clinical studies on this subject. [ABSTRACT FROM AUTHOR]

The fairly low power density, mainly resulting from poor electroactive bacterial (EAB) adhesion and the sluggish extracellular electron transfer (EET) at the anode interface, constrains the practical implementation of microbial fuel cells (MFCs). Therefore, the properties of the anode material are considered to be a crucial factor for the long-term operational performance of MFCs. In order to enhance the power production performance of MFCs, an aerogel composed of Fe, N, and S co-doped carbon nanofibers (CNFs) and reduced graphene oxide (rGO) was employed as a high-performance anode material by electrospinning, high-temperature pyrolysis and freeze-drying. The doping of Fe, N and S elements induced the formation of abundant reactive sites on the CNFs, which enhanced the electrochemical performance of the anode and the EET process. The huge electroactive area of the samples facilitated the formation of dense biofilms. Therefore, an MFC with the FeS/Fe3C@NCNFs/rGO-modified anode achieved a maximum power density of 2792.56 mW m−2 and the highest output voltage of 0.658 V, both of which were significantly higher than those of the carbon cloth anode (773.97 mW m−2 and 0.443 V). Considering the great improvement in power production, it has considerable potential as a low-cost but high-performance anode material for MFCs. [ABSTRACT FROM AUTHOR]

Human dentin is a highly organized dental tissue displaying a complex microarchitecture consisting of micrometer-sized tubules encased in a mineralized type-I collagen matrix. As such, it serves as an important substrate for the adhesion of microbial colonizers and oral biofilm formation in the context of dental caries disease, including root caries in the elderly. Despite this issue, there remains a current lack of effective biomimetic in vitro dentin models that facilitate the study of oral microbial adhesion by considering the surface architecture at the micro- and nanoscales. Therefore, the aim of this study was to develop a novel in vitro microfabricated biomimetic dentin surface that simulates the complex surface microarchitecture of exposed dentin. For this, a combination of soft lithography microfabrication and biomaterial science approaches were employed to construct a micropitted PDMS substrate functionalized with mineralized type-I collagen. These dentin analogs were subsequently glycated with methylglyoxal (MGO) to simulate dentin matrix aging in vitro and analyzed utilizing an interdisciplinary array of techniques including atomic force microscopy (AFM), elemental analysis, and electron microscopy. AFM force-mapping demonstrated that the nanomechanical properties of the biomimetic constructs were within the expected biological parameters, and that mineralization was mostly predominated by hydroxyapatite deposition. Finally, dual-species biofilms of Streptococcus mutans and Candida albicans were grown and characterized on the biofunctionalized PDMS microchips, demonstrating biofilm-specific morphologic characteristics and confirming the suitability of this model for the study of early biofilm formation under controlled conditions. Overall, we expect that this novel biomimetic dentin model could serve as an in vitro platform to study oral biofilm formation or dentin–biomaterial bonding in the laboratory without the need for animal or human tooth samples in the future. [ABSTRACT FROM AUTHOR]

Breast cancer is the most common cancer in women globally, often necessitating mastectomy and subsequent breast reconstruction. Silicone mammary implants (SMIs) play a pivotal role in breast reconstruction, yet their interaction with the host immune system and microbiome remains poorly understood. This study investigates the impact of SMI surface topography on host antimicrobial responses, wound proteome dynamics, and microbial colonization. Biological samples were collected from ten human patients undergoing breast reconstruction with SMIs. Mass spectrometry profiles were analyzed for acute and chronic wound proteomes, revealing a nuanced interplay between topography and antimicrobial response proteins. 16S rRNA sequencing assessed microbiome dynamics, unveiling topography-specific variations in microbial composition. Surface topography alterations influenced wound proteome composition. Microbiome analysis revealed heightened diversity around rougher SMIs, emphasizing topography-dependent microbial invasion. In vitro experiments confirmed staphylococcal adhesion, growth, and biofilm formation on SMI surfaces, with increased texture correlating positively with bacterial colonization. This comprehensive investigation highlights the intricate interplay between SMI topography, wound proteome dynamics, and microbial transmission. The findings contribute to understanding host–microbe interactions on SMI surfaces, essential for optimizing clinical applications and minimizing complications in breast reconstruction. [ABSTRACT FROM AUTHOR]

Aims This study aimed to investigate the changes of cell membrane structure and function of Issatchenkia terricola under citric acid by performing physiological analysis. Methods and results The membrane integrity, surface hydrophobicity, structure, fluidity, apoptosis, and fatty acid methyl esters composition of I. terricola WJL-G4 cells were determined by propidium iodide staining, microbial adhesion to hydrocarbon test, transmission electron microscopy analysis, fluorescence anisotropy, flow cytometry, and gas chromatography-mass, respectively. The results showed that with the increasing of citric acid concentrations, the cell vitality, membrane integrity, and fluidity of I. terricola reduced; meanwhile, apoptosis rate, membrane permeable, hydrophobicity, and ergosterol contents augmented significantly. Compared to control, the activities of Na+, K+-ATPase, and Ca2+, Mg2+-ATPase increased by 3.73-fold and 6.70-fold, respectively, when citric acid concentration increased to 20 g l−1. The cells cracked and their cytoplasm effused when the citric acid concentration reached 80 g l−1. Conclusions I. terricola could successfully adjust its membrane structure and function below 60 g l−1 of citric acid. However, for citric acid concentrations above 80 g l−1, its structure and function were dramatically changed, which might result in reduced functionality. [ABSTRACT FROM AUTHOR]

6-Iodo-substituted carboxy-quinolines were obtained using a one-pot, three-component method with trifluoroacetic acid as a catalyst under acidic conditions. Iodo-aniline, pyruvic acid and 22 phenyl-substituted aldehydes (we varied the type and number of radicals) or O-heterocycles, resulting in different electronic effects, were the starting components. This approach offers advantages such as rapid response times, cost-effective catalysts, high product yields and efficient purification procedures. A comprehensive investigation was conducted to examine the impact of aldehyde structure on the synthesis pathway. A library of compounds was obtained and characterized by FT-IR, MS, 1H NMR and 13C NMR spectroscopy and single-ray crystal diffractometry. Their antimicrobial activity against S. epidermidis, K. pneumonie and C. parapsilosis was tested in vitro. The effect of iodo-quinoline derivatives on microbial adhesion, the initial stage of microbial biofilm development, was also investigated. This study suggests that carboxy-quinoline derivatives bearing an iodine atom are interesting scaffolds for the development of novel antimicrobial agents. [ABSTRACT FROM AUTHOR]

Marine plastic pollution is rapidly colonized by a biofilm of microorganisms associated with the control of biogeochemical cycles, plastic biodegradation, and potentially pathogenic activities. An extensive number of studies have described the taxonomic composition of this biofilm, referred to as the 'plastisphere', and previous reviews have reported on the influence of location, plastic type, and plastic-biodegradation ability on plastisphere formation. However, few studies have investigated the metabolic activity of this complex biofilm and how microbial pathogenicity and bioremediation could be regulated in this ecosystem. In this review, we highlight the understudied molecular and abiotic factors influencing plastisphere formation and microbial functioning beyond taxonomic description. In this context, we critically discuss the impacts of (i) organism-organism interaction, (ii) microbial cell wall composition, and (iii) commonly encountered plastic-bound co-pollutants (heavy metals, persistent organic pollutants, UV filters). For the first time, we review the anticipated impact of lipophilic organic UV-filters – found in plastic additives and sunscreens – on the plastisphere due to their reported affinity for plastics, persistence, and co-location at high concentrations in touristic coastal environments. Herein, we integrate the findings of 34 global studies exploring plastisphere composition, 35 studies quantifying co-pollutant concentrations, and draw upon 52 studies of cell -cell and -substrate interaction to deduce the inferred, yet still unknown, metabolic interactions within this niche. Finally, we provide novel future directions for the advancement of functional plastisphere research applying advanced molecular tools to new, and appropriate research questions. Data was compiled from 97 plastispheres across 34 different studies and an additional 87 studies relating to the impacts of plastisphere components on microbial species. The biotic and abiotic factors influencing microbial adhesion to different plastic polymers, including cell wall composition, and plastisphere location are considered. The impacts of heavy metals and organic co-pollutants – and for the first time, organic UV-filters – on plastisphere formation and function are reviewed and discussed. A change in direction from novel research questions to the use of state-of-the-art methodologies are recommended for the advancement of functional plastisphere research. [ABSTRACT FROM AUTHOR]

Joint replacement is a common surgery and is predominantly utilized for treatment of osteoarthritis in the aging population. The longevity of many of these implants depends on bony ingrowth. Here, we provide an overview of current techniques in osteogenesis (inducing bone growth onto an implant), which is affected by aging and inflammation. In this review we cover the biologic underpinnings of these processes as well as the clinical applications. Overall, aging has a significant effect at the cellular and macroscopic level that impacts osteosynthesis at bone-metal interfaces after joint arthroplasty; potential solutions include targeting prolonged inflammation, preventing microbial adhesion, and enhancing osteoinductive and osteoconductive properties. [ABSTRACT FROM AUTHOR]

The rapid emergence of multidrug-resistant pathogens worldwide has raised concerns regarding the effectiveness of conventional antibiotics. This can be observed in ESKAPE pathogens, among others, whose multiple resistance mechanisms have led to a reduction in effective treatment options. Innovative strategies aimed at mitigating the incidence of antibiotic-resistant pathogens encompass the potential use of biosurfactants. These surface-active agents comprise a group of unique amphiphilic molecules of microbial origin that are capable of interacting with the lipidic components of microorganisms. Biosurfactant interactions with different surfaces can affect their hydrophobic properties and as a result, their ability to alter microorganisms' adhesion abilities and consequent biofilm formation. Unlike synthetic surfactants, biosurfactants present low toxicity and high biodegradability and remain stable under temperature and pH extremes, making them potentially suitable for targeted use in medical and pharmaceutical applications. This review discusses the development of biosurfactants in biomedical and therapeutic uses as antimicrobial and antibiofilm agents, in addition to considering the potential synergistic effect of biosurfactants in combination with antibiotics. Furthermore, the anti-cancer and anti-viral potential of biosurfactants in relation to COVID-19 is also discussed. [ABSTRACT FROM AUTHOR]

This hypothesis demonstrates that the efficiency of loop-mediated isothermal amplification (LAMP) for nucleic acid detection can be positively influenced by the preconcentration of microbial cells onto hydrophobic paper surfaces. The mechanism of this model is based on the high affinity of microbes towards hydrophobic surfaces. Extensive studies have demonstrated that hydrophobic surfaces exhibit enhanced bacterial and fungal adhesion. By exploiting this inherent affinity of hydrophobic paper substrates, the preconcentration approach enables the adherence of a greater number of target cells, resulting in a higher concentration of target templates for amplification directly from urine samples. In contrast to conventional methods, which often involve complex procedures, this approach offers a simpler, cost-effective, and user-friendly alternative. Moreover, the integration of cell adhesion, LAMP amplification, and signal readout within paper origami-based devices can provide a portable, robust, and highly efficient platform for rapid nucleic acid detection. This innovative hypothesis holds significant potential for point-of-care (POC) diagnostics and field surveillance applications. Further research and development in this field will advance the implementation of this technology, contributing to improved healthcare systems and public health outcomes. [ABSTRACT FROM AUTHOR]

Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria‐repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria‐repellent surfaces lies in the contactless and aseptic large‐area laser‐processing of technical surfaces. Tailored surface textures, enabled by different laser‐processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state‐of‐the‐art review of laser‐surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser‐processed surfaces, the challenges of anti‐microbial surface designs are discussed, and future directions will be outlined. [ABSTRACT FROM AUTHOR]

This critical review for anaerobic degradation of complex organic compounds like butyrate using reactors has been enormously applied for biogas production. Biogas production rate has a great impact on: reactor granulation methanogenesis, nutrient content, shear velocity, organic loading and loss of nutrients taking place in the reactor continuously. Various technologies have been applied to closed anaerobic reactors to improve biogas production and treatment efficiency. Recent reviews showed that the application of closed anaerobic reactors can accelerate the degradation of organics like volatile fatty acid-butyrate and affect microbial biofilm formation by increasing the number of methanogens and increase methane production 16.5 L−1 CH4 L−1 POME−1. The closed anaerobic reactors with stable microbial biofilm and established organic load were responsible for the improvement of the reactor and methane production. The technology mentioned in this review can be used to monitor biogas concentration, which directly correlates to organic concentrations. This review attempts to evaluate interactions among the: degradation of organics, closed anaerobic reactors system, and microbial granules. This article provides a useful picture for the improvement of the degradation of organic butyrate for COD removal, biogas and methane production in an anaerobic closed reactor. Recent reviews showed that the application of closed anaerobic reactors can accelerate the degradation of organic compounds, such as volatile fatty acid-butyrate, and affect microbial biofilm formation by increasing the number of methanogens, thus enhancing biogas production. The closed anaerobic reactors with stable microbial biofilm established the organic load and improved the performance of the reactor for methane production. The technology used involves monitoring biogas concentrations which correlates with organic concentrations. This review attempts to evaluate interactions among: the degradation of organics, closed anaerobic reactors system, and microbial granules. This review, therefore, provides a useful picture for the improvement of butyrate degradation for COD removal and methane production with the help of various anaerobic closed reactors. The performance of UASBR depends on granulation. The granulation process in UASB reactors can be divided into four steps: (1) Transport of cells to the surface of other cells; (2) Initial reversible adsorption by physicochemical forces; (3) Irreversible adhesion of the cells by microbial appendages and/or polymers; and (4) Multiplication of the cells and development of the granules. Any factor which can complement any one of the four steps will be able to accelerate the granulation process and shorten the startup time of UASB reactors. [ABSTRACT FROM AUTHOR]

This investigation examined the role of shear stress on the dynamic development of microbial communities within anodic biofilms in single-chamber microbial fuel cells (MFCs). Bacterial attachment to surfaces, often regarded as a crucial step in biofilm formation, may significantly contribute to the selection of electroactive bacteria (EAB). It is well established that hydrodynamic forces, particularly shear forces, have a profound influence on bacterial adhesion. This study postulates that shear stress could select EAB on the anode during the adhesion phase by detaching non-EAB. To examine this hypothesis, MFC reactors equipped with a shear stress chamber were constructed, creating specific shear stress on the anode. The progression of adhesion under various shear stress conditions (1, 10, and 50 mPa) was compared with a control MFC lacking shear stress. The structure of the microbial community was assessed using 16S rRNA gene (rrs) sequencing, and the percentage of biofilm coverage was analyzed using fluorescence microscopy. The results indicate a significant impact of shear stress on the relative abundance of specific EAB, such as Geobacter, which was higher (up to 30%) under high shear stress than under low shear stress (1%). Furthermore, it was noted that shear stress decreased the percentage of biofilm coverage on the anodic surface, suggesting that the increase in the relative abundance of specific EAB occurs through the detachment of other bacteria. These results offer insights into bacterial competition during biofilm formation and propose that shear stress could be utilized to select specific EAB to enhance the electroactivity of anodic biofilms. However, additional investigations are warranted to further explore the effects of shear stress on mature biofilms. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are common xenobiotics that are detrimental to the environment and human health. Bacterial endophytes, having the capacity to degrade PAHs, and plant growth promotion (PGP) may facilitate their biodegradation. In this study, phenanthrene (PHE) utilization of a newly isolated PGP endophytic strain of Pseudomonas chlororaphis 23aP and factors affecting the process were evaluated. The data obtained showed that strain 23aP utilized PHE in a wide range of concentrations (6–100 ppm). Ethyl-acetate-extractable metabolites obtained from the PHE-enriched cultures were analyzed by gas chromatography–mass spectrometry (GC-MS) and thin-layer chromatography (HPTLC). The analysis identified phthalic acid, 3-(1-naphthyl)allyl alcohol, 2-hydroxybenzalpyruvic acid, α-naphthol, and 2-phenylbenzaldehyde, and allowed us to propose that the PHE degradation pathway of strain 23aP is initiated at the 1,2-, 3,4-carbon positions, while the 9,10-C pathway starts with non-enzymatic oxidation and is continued by the downstream phthalic pathway. Moreover, the production of the biosurfactants, mono- (Rha-C8-C8, Rha-C10-C8:1, Rha-C12:2-C10, and Rha-C12:1-C12:1) and dirhamnolipids (Rha-Rha-C8-C10), was confirmed using direct injection–electrospray ionization–mass spectrometry (DI-ESI-MS) technique. Changes in the bacterial surface cell properties in the presence of PHE of increased hydrophobicity were assessed with the microbial adhesion to hydrocarbons (MATH) assay. Altogether, this suggests the strain 23aP might be used in bioaugmentation—a biological method supporting the removal of pollutants from contaminated environments. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate (PMMA) acrylic resin is the most used material in dentistry for making prosthetic devices. The polymerization process can cause material failure, which favors the adhesion of microorganisms and reduces the properties of the acrylic resin in clinical practice. Therefore, the objective of this study was to carry out a systematic review in order to answer the question "What is the relation between porosity, wettability, sorption, and solubility properties of acrylic resins incorporated with antimicrobials?" The electronic search of the articles was carried out in four databases and articles published between 2012 and May 2022 were selected. The search terms were: (("acrylic resin" OR PMMA OR polymethylmethacrylate OR methacrylate) AND (antimicrobial OR antifungal OR antibacterial OR nanoparticle) AND (porosity OR wettability OR "sorption and solubility" OR "microbial adesion")). One thousand three hundred thirty articles were found in the databases, after removing the duplicates, 932 were analyzed by title and abstract, of these, 11 were selected for full reading, of which 06 met the inclusion criteria and were selected for review. After descriptive analysis, it can be concluded that acrylic resins incorporated with antimicrobials can maintain the ideal physicochemical properties for the clinical functioning of the material. [ABSTRACT FROM AUTHOR]

Peri-implant infection is rapidly becoming an – if not the most – important clinical challenge for indwelling medical devices. To alleviate the global rise in antibiotic use for the treatment of such infections, a plethora of biomaterials/bioengineering-based antimicrobial strategies are emerging to restrict or ideally to eliminate microbial adhesion and biofilm formation on implant surfaces. Yet, the development of such approaches faces specific challenges, like biocompatibility concerns, reduced antimicrobial effectiveness, long-term stability issues and antibiotic resistance development, which limit translation to the clinic. This review provides insights into the antimicrobial activity of current state-of-the-art biomaterial-based approaches to address the aforementioned issues. Translational research strategies and regulatory framework are also emphasised as key elements facilitating clinical implementation of anti-infective biomaterials. This review closes with the vision that the integration of computational tools and experimental databases using artificial intelligence (AI) would provide new insights for the accelerated development of next-generation biomaterial-based antimicrobial strategies. [ABSTRACT FROM AUTHOR]

A multimeric glycoprotein of blood plasma—Von Willebrand factor (VWF)—mediates platelet adhesion to the fibrillar collagen of the subendothelial matrix if the blood vessel walls are damaged. The adsorption of VWF to collagen is thus essential for the initial stages of platelet hemostasis and thrombosis, as it plays a role of a molecular bridge between the injury and platelet adhesion receptors. Biomechanical complexity and sensitivity to the hydrodynamics are inherent in this system, therefore, modern computational methods supplement experimental studies of biophysical and molecular mechanisms that underlie platelet adhesion and aggregation in the blood flow. In the present paper, we propose a simulation framework for the VWF‐mediated platelet adhesion to a plane wall with immobilized binding sites for VWF under the action of shear flow. VWF multimers and platelets are represented in the model by particles connected by elastic bonds and immersed in a viscous continuum fluid. This work complements the scientific field by taking into account the shape of a flattened platelet, but keeping a compromise between the detail of the description and the computational complexity of the model. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of hydrophobic glass surfaces in reducing microbial populations on touch-enabled digital devices. Hydrophobic coatings have been proposed as a potential solution to minimize microbial adhesion and growth on device surfaces. Here, we intended to investigate the effect of hydrophobic spray on microbial load. The results were quantitatively analyzed using microbiological techniques. the nonhydrophobic surface harbors gradual microbial buildup upon time, such as threefold increase from 2 to 4 h and fivefold increase to 6 h post initial sampling with 143.6 ± 33.89 cfu/ml increase up to 264.7 ± 28.53 cfu/ml, whereas the hydrophobic surface had an overall build-up from 16.6 ± 1.2 to 50.45 ± 11.12 cfu/ml with P < 0.0001 significance. This research provides valuable insights into the potential application of hydrophobic glass coatings to mitigate microbial contamination on touch-enabled digital devices, enhancing their hygienic properties and minimizing the risk of infectious disease transmission. [ABSTRACT FROM AUTHOR]

This study evaluated surface properties and adhesion/biofilm formation by Candida albicans on 3D printed denture base resins used in 3D printing. Disc-shaped specimens (15 mm x 3 mm) of two 3D-printed resins (NextDent Denture 3D+, NE, n = 64; and Cosmos Denture, CO, n = 64) and a heat-polymerized resin (Lucitone 550, LU, control, n = 64) were analyzed for surface roughness (Ra μm) and surface free energy (erg cm-2). Microbiologic assays (90-min adhesion and 48-h biofilm formation by C. albicans) were performed five times in triplicate, with the evaluation of the specimens' surface for: (i) colony forming units count (CFU/mL), (ii) cellular metabolism (XTT assay), and (iii) fluorescence and thickness of biofilm layers (confocal laser scanning microscopy). Data were analyzed using parametric and nonparametric tests (α = 0.05). LU presented higher surface roughness Ra (0.329±0.076 μm) than NE (0.295±0.056 μm) (p = 0.024), but both were similar to CO (0.315±0.058 μm) (p = 1.000 and p = 0.129, respectively). LU showed lower surface free energy (47.47±2.01 erg cm-2) than CO (49.61±1.88 erg cm-2) and NE (49.23±2.16 erg cm-2) (p<0.001 for both). The CO and NE resins showed greater cellular metabolism (p<0.001) and CO only, showed greater colonization (p = 0.015) by C. albicans than LU in the 90-min and 48-hour periods. It can be concluded that both 3D-printed denture base resins are more prone to colonization by C. albicans, and that their surface free energy may be more likely associated with that colonization than their surface roughness. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of biofilms on different surfaces continues to be a major public health problem. The antimicrobial resistance and the difficulty of finding drugs capable of combating these established biofilms generates the urgent need to find compounds that prevent cells from settling and establishing of these complex communities of microorganisms. Zwitterionic modification of nanomaterials allows the formation of a hydration layer, and this highly hydrophilic surface provides antifouling properties as well as a good biocompatibility by preventing non-specific interactions. Thus, they are appropriate candidates to prevent microbial adhesion to different surfaces and, in consequence, avoid biofilm formation. For this reason, we have incorporated zwitterionic moieties in multivalent systems, as are carbosilane dendrimers. Characterization of these systems was performed using nuclear magnetic resonance and mass spectrometry. It has been analysed if the new molecules have capacity to inhibit the biofilm formation in Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The results showed that they were more effective against S. aureus, observing a biofilm reduction of 81.5% treating with 32 mg/L of G2SiZWsf dendrimer and by 72.5% using 32 mg/L of the G3SiZWsf dendrimer. Finally, the absence of cytotoxicity was verified by haemolysis and cytotoxicity studies in human cells lines. [ABSTRACT FROM AUTHOR]

Microbial adhesion on dental restorative materials may jeopardize the restorative treatment long-term outcome. The goal of this in vitro study was to assess Candida albicans capability to adhere and form a biofilm on the surface of heat-cured dental composites having different formulations but subjected to identical surface treatments and polymerization protocols. Three commercially available composites were evaluated: GrandioSO (GR), Venus Diamond (VD) and Enamel Plus HRi Biofunction (BF). Cylindrical specimens were prepared for quantitative determination of C. albicans S5 planktonic CFU count, sessile cells CFU count and biomass optical density (OD570 nm). Qualitative Concanavalin-A assays (for extracellular polymeric substances of a biofilm matrix) and Scanning Electron Microscope (SEM) analyses (for the morphology of sessile colonies) were also performed. Focusing on planktonic CFU count, a slight but not significant reduction was observed with VD as compared to GR. Regarding sessile cells CFU count and biomass OD570 nm, a significant increase was observed for VD compared to GR and BF. Concanavalin-A assays and SEM analyses confirmed the quantitative results. Different formulations of commercially available resin composites may differently interact with C. albicans. The present results showed a relatively more pronounced antiadhesive effect for BF and GR, with a reduction in sessile cells CFU count and biomass quantification. [ABSTRACT FROM AUTHOR]

Microbial colonization on various surfaces is a serious problem. Biofilms from these microbes pose serious health and economic threats. In addition, the recent global pandemic has also attracted great interest in the latest techniques and technology for antimicrobial surface coatings. Incorporating antimicrobial nanocompounds into materials to prevent microbial adhesion or kill microorganisms has become an increasingly challenging strategy. Recently, many studies have been conducted on the preparation of nanomaterials with antimicrobial properties against diseases caused by pathogens. Despite tremendous efforts to produce antibacterial materials, there is little systematic research on antimicrobial coatings. In this article, we set out to provide a comprehensive overview of nanomaterials-based antimicrobial coatings that can be used to stop the spread of contamination to surfaces. Typically, surfaces can be simple deposits of nanomaterials, embedded nanomaterials, as well as nanotubes, nanowires, nanocolumns, nanofibers, nanoneedles, and bio-inspired structures. [ABSTRACT FROM AUTHOR]

Background: Bacterial surface proteins play key roles in pathogenicity and often contribute to microbial adhesion and invasion. Pasteurella lipoprotein E (PlpE), a Pasteurella multocida (P. multocida) surface protein, has recently been identified as a potential vaccine candidate. Live attenuated Salmonella strains have a number of potential advantages as vaccine vectors, including immunization with live vector can mimic natural infections by organisms, lead to the induction of mucosal, humoral, and cellular immune responses. In this study, a previously constructed recombinant attenuated Salmonella Choleraesuis (S. Choleraesuis) vector rSC0016 was used to synthesize and secrete the surface protein PlpE of P. multocida to form the vaccine candidate rSC0016(pS-PlpE). Subsequently, the immunogenicity of S. Choleraesuis rSC0016(pS-PlpE) as an oral vaccine to induce protective immunity against P. multocida in mice was evaluated. Results: After immunization, the recombinant attenuated S. Choleraesuis vector can efficiently delivered P. multocida PlpE protein in vivo and induced a specific immune response against this heterologous antigen in mice. In addition, compared with the inactivated vaccine, empty vector (rSC0016(pYA3493)) and PBS immunized groups, the rSC0016(pS-PlpE) vaccine candidate group induced higher antigen-specific mucosal, humoral and mixed Th1/Th2 cellular immune responses. After intraperitoneal challenge, the rSC0016(pS-PlpE) immunized group had a markedly enhanced survival rate (80%), a better protection efficiency than 60% of the inactivated vaccine group, and significantly reduced tissue damage. Conclusions: In conclusion, our study found that the rSC0016(pS-PlpE) vaccine candidate provided good protection against challenge with wild-type P. multocida serotype A in a mouse infection model, and may potentially be considered for use as a universal vaccine against multiple serotypes of P. multocida in livestock, including pigs. [ABSTRACT FROM AUTHOR]

Full and partial restorations in dentistry must replicate the characteristics of the patient's natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ΔE between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are smoother and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans. [ABSTRACT FROM AUTHOR]

The challenge of concurrently resisting corrosion, wear, and microbial adhesion in marine equipment necessitates the development of advanced protective coatings for moving parts. Leveraging the unique properties of constituent phases in nanocomposite materials offers a promising approach. Here, we report the development of a high-performance protective coating material combining hard, anti-corrosive, and antifouling TaB 2 phase with a self-lubricating amorphous carbon (a-C) phase. The synthesized specimens form an "a-C embedded in TaCB solid solution" (a-C/TaCB) structure at 8 at.% carbon content and transition to a "TaCB solid solution embedded in a-C" (TaCB/a-C) structure at 18.8 at.% carbon content. The a-C/TaCB coating demonstrates enhanced tribological, corrosion and tribocorrosion performances compared to the TaB 2 coating, while maintaining excellent mechanical and antifouling performances without the usual deterioration caused by an excess soft biocompatible a-C phase. The rational design of this dual-phase nanocomposite structure could facilitate the development of a unique class of protective coating materials tailored to meet the stringent requirements of harsh marine environments. [ABSTRACT FROM AUTHOR]

Aim: To study the microbial adhesion on different orthodontic brackets (conventional, ceramic, and self-ligating brackets). Materials and Methods: Three types of bracket systems i.e. self-ligating, conventional, and ceramic brackets were used consisting of 10 patients for each bracket system. Out of 30 patients 20 patients will be treated with conventional and ceramic brackets, in which, in one-half of the mouth steel ligature ties are placed and in the other half elastomeric rings would be placed. We collected swabs from the central incisors and first premolars of the both the right and left sides of both the maxillary and mandibular arches. The samples were collected three times from the above-mentioned teeth once prior to the placement of the brackets, the second and third samples after one and three months respectively. Result: Significant variations were between the pretreatment and after one and three months of bracket placement in all three groups. Significant increase in the microbial adhesion of aerobic and anaerobic bacteria in conventional bracket form pretreatment to one and three months after bracket placement is seen. Although the colony formed by anaerobic bacteria is more in number in comparison to the aerobic bacteria. Conclusion: Our study reveals that the most hygienic bracket is a self-ligating bracket that should be used in patients who have poor oral hygiene. We also found that using steel ligature is more suitable as compared to elastomeric ligature in both conventional and ceramic brackets. [ABSTRACT FROM AUTHOR]

After a total laryngectomy, voice rehabilitation is essential for a patient to successfully reintegrate into society. The implantation of a voice prosthesis (VP) is the gold standard to achieve this goal. Thus, the primary disadvantage of using VP is the fluid blockage and degradation caused by biofilm colonization, which requires frequent replacements, associated with a poor quality of life for the patient. Many scientists have centered their research on coming up with novel and efficient ways to combat polymicrobial biofilms, both in terms of preventing microbial adhesion and rupturing established biofilms in order to overcome this limitation. This paper aims to present the current state of the art regarding biofilm formation on VPs and composition of VPs, and to review the current anti-biofilm strategies that have proven to be successful, as well as pointing possible novel perspectives of improvement. [ABSTRACT FROM AUTHOR]

Polymer cables are being applied increasingly in fields such as deep‐sea mooring and cage culture. How to improve their wear resistance and prevent microbial adhesion is an urgent problem to be solved. In this work, the surface of the cable was treated by the polyvinylpyrrolidone cross‐linking method and the anchoring effect of one‐dimensional linear nanomaterials, which improved the adhesion of the water‐based coating. Meanwhile, the protective effect of the coating was improved through the addition of antifouling agents and wear‐resistant agents. The microstructure and intermolecular forces of the coating were characterized by scanning electron microscopy and infrared spectroscopy. The net hanging test results show that the surface‐treated cable exhibits better abrasion resistance and antifouling effects, and the shedding phenomenon is significantly improved. [ABSTRACT FROM AUTHOR]

[Display omitted] Bioinspired superhydrophobic surfaces have offered unique advantages in combating microbial contaminations involving fungi, bacteria, and viruses, especially during the global COVID-19 pandemic. It has been widely accepted that the biofouling-resistant capability of the superhydrophobic substrates principally arises from the entrapped air-layer. With this principle, substantial consideration is devoted to designing superhydrophobic surfaces with an emphasis on stabilizing the air-layer. However, some superhydrophobic surfaces were proven to promote the attachment of microorganisms in certain cases, implying that the mechanisms governing the capacity of superhydrophobic surfaces to mediate microbial adhesion still need to be better understood. Here, we review recent efforts in elucidating the inter-relationship between surface superhydrophobicity and microbial adhesion to make a generalizable consensus on why some superhydrophobic surfaces can repel microbes while others may be incapable. In this context, we shed light on the fact that surface topography and low surface energy are not only the requirements to develop superhydrophobic surfaces but also play a decisive role in endowing surfaces with improved anti-adhesive properties. The obtained viewpoints ideally pave the way for engineering functional superhydrophobic surfaces that effectively reduce microbial contamination on a predetermined basis and can potentially be applied to high-touch surfaces, biomaterial surfaces, personal protective equipment (PPE), and other medical equipment. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the initial bacterial adhesion on 3D-printed splint materials in relation to their surface properties. Materials and methods: Specimens of five printable splint resins (SHERAprint-ortho plus UV, NextDent Ortho Rigid, LuxaPrint Ortho Plus, V-Print Splint, KeySplint Soft), one polymethylmethacrylate (PMMA) block for subtractive manufacturing (Astron CLEARsplint Disc), two conventional powder/liquid PMMA materials (FuturaGen, Astron CLEARsplint), and one polyethylene terephthalate glycol (PETG) thermoplastic sheet for vacuum forming (Erkodur Thermoforming Foil) were produced and finished. Surface roughness Ra was determined via contact profilometry. Surface morphology was examined under a scanning electron microscope. Multi-species bacterial biofilms were grown on entire splints. Total biofilm mass and viable bacterial counts (CFU/ml) within the biofilms were determined. Statistical analyses were performed with a one-way ANOVA, Tukey's post hoc test, and Pearson's test (p < 0.05). Results: Astron CLEARsplint and KeySplint Soft specimens showed the highest surface roughness. The mean total biofilm mass on KeySplint Soft splints was higher compared to all other materials (p < 0.05). Colony-forming unit per milliliter on FuturaGen, Astron CLEARsplint, and KeySplint Soft splints was one log scale higher compared to all other materials. The other four printable resins displayed overall lower Ra, biofilm mass, and CFU/ml. A positive correlation was found between Ra and CFU/ml (r = 0.69, p = 0.04). Conclusions: The 3D-printed splints showed overall favorable results regarding surface roughness and bacterial adhesion. Thermoplastic materials seem to display a higher surface roughness, making them more susceptible to microbial adhesion. Clinical relevance: The development of caries and gingivitis in patients with oral appliances may be affected by the type of material. [ABSTRACT FROM AUTHOR]

The cell surface physicochemical properties of Streptomyces should influencing the dispersal and adsorption of spores and hyphae in soil and should conditioning there interactions with organic or metal substances in the bioremediation of contaminated environment. These properties are concerning surface hydrophobicity, electron donor/acceptor, and charge surface. To date, only hydrophobicity of Streptomyces was studied by contact angle measurements and microbial adhesion to hydrocarbons (MATH). In this work, we studied the electron donor/acceptor character of the Streptomyces cell surface in two ionic strength 10−3 M and 10−1 M of KNO3. Thus, to facilitate the characterisation of the surfaces of microbial cells, we used a simple, rapid, and quantitative technique, the microbial adhesion method to solvents (MATS), which is based on the comparison of the affinity of microbial cells for a monopolar solvent with a polar solvent. The monopolar solvent can be acid (electron acceptor) or basic (electron donor), but both solvents should have a surface tension similar to that of the Kifshitz van der Waals components. At the significant ionic strength of the biological medium, the electron donor character is well expressed for all 14 Streptomyces strains with very significant differences among them ranging from 0% to 72.92%. When the cells were placed in a solution with a higher ionic strength, we were able to classify the donor character results into three categories. The first category is that the weak donor character of strains A53 and A58 became more expressed at 10−1 M KNO3 concentration. The second category is that three strains A30, A60, and A63 expressed a weaker character in a higher ionic strength. For the other strains, no expression of the donor trait was obtained at higher ionic strength. In a suspension with a concentration of 10−3 KNO3, only two strains expressed an electron acceptor character. This character is very important for strains A49, A57, A58, A60, A63, and A65 at 10−1M KNO3. This work has shown that these properties vary greatly depending on the Streptomyces strain. It is important to consider the change in physicochemical properties of surface cells with ionic strength when using Streptomyces in different bioprocesses. [ABSTRACT FROM AUTHOR]

Dental polymers are now available as monolithic materials which can be readily used in computer-aided design and computer-aided manufacturing (CAD/CAM) systems. Despite possessing numerous advantages over conventionally produced polymers, the polymers produced by either of these systems fail to exhibit immunity to surface microbial adhesion when introduced into the oral environment, leading to the development of oral diseases. The aim of this study was to analyze the biofilm formation of six microorganisms from the oral cavity and its correlation to the surface characteristics of CAD/CAM dental polymers. A total of ninety specimens were divided into three groups: resin-based composite, polymethyl methacrylate, and polyether ether ketone. The experimental procedure included surface roughness and water contact angle measurements, colony forming unit counting, and scanning electron microscopy analysis of biofilm formed on the surface of the tested materials. The data were analyzed using the Kruskal–Wallis test, with a Dunn's post hoc analysis, and one way analysis of variance, with a Tukey's post hoc test; the correlation between the measurements was tested using Spearman's correlation coefficient, and descriptive statistics were used to present the data. Despite using the same manufacturing procedure, as well as the identical manufacturer's finishing and polishing protocols, CAD/CAM dental polymers revealed significant differences in surface roughness and water contact angle, and the increased values of both parameters led to an increase in biofilm formation on the surface of the materials. The CAD/CAM resin-based composite showed the lowest number of adhered microorganisms compared to CAD/CAM polymethyl methacrylate and CAD/CAM polyether ether ketone. [ABSTRACT FROM AUTHOR]

Diffuse coplanar surface barrier discharge (DCSBD) was used to activate the opposite side of the plasma‐exposed linear low‐density polyethylene/polyamide (LLDPE/PA) tubular film of multilayer casing. We determined that conductive metal rubber roller in the DCSBD system allowed the formation of microfilaments perpendicular to the film surface, resulting in improved wettability and adhesion of inner LLDPE side of the tubular film. These findings were supported by increasing the concentration of polar functional groups. Based on these remarkable outcomes obtained after a very short plasma exposure time of 0.5 s, DCSBD roll‐to‐roll system in proper arrangement affords adhesion improvement of the opposite side of the treated film without any material damage, hence can compete with industrial corona in commercial sphere of plasma treatments. [ABSTRACT FROM AUTHOR]

Background and Objectives: Adhesion of microorganisms on facemask surfaces is a major problem that produces contamination of the mask wearer either by inhalation or by direct contact. Generally, physicochemical properties of the material and the microorganism are responsible for this adhesion and are also reported to influence the filtration efficiency of facemasks. However, theses surface proprieties and their effect on particles attachment on facemask materials remain poorly documented. The purpose of this study was to investigate the physicochemical properties of seven facemasks and evaluate the influence of these characteristics on the adhesion of Sataphylococcus aureus. Materials and Methods: Physicochemical properties is done by contact angle method and scanning electron microscopy while theoretical adhesion of S. aureus is done according to XDLVO approach. Results: The obtained results showed that all masks have a hydrophobic character. The electron donor and electron acceptor parameters change depending on each mask. Chemical analysis demonstrates the presence of two chemical elements (carbon and oxygen). Predictive adhesion demonstrate that S. aureus has an attractive behavior towards the masks used but the potential of adhesion is not the same. Conclusion: Such information is valuable to understand attachment of biological particles and to contribute in the inhibition of this attachment. [ABSTRACT FROM AUTHOR]

Fermented foods and beverages are rich source of probiotic microorganisms and yeasts are the most common microorganisms found in these fermented products. Fermented beverages are less explored for probiotics, therefore; the present study was focused on isolation, screening and characterization of probiotic yeast from rice Chhang, a fermented beverage of Lahaul Spiti. Ten yeast isolates were initially isolated from rice Chhang and out of which two isolates Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197 were selected based on their antimicrobial activity. These two yeast isolates were examined for various probiotic properties such as survival at low pH, bile tolerance, microbial adhesion to hydrocarbons, cholesterol assimilation, exopolysaccharide production and haemolytic activity. Both isolates showed antimicrobial activity against all the tested pathogens used in this study, also showed high acid tolerance at pH 2 and pH 3 and can withstand high bile concentration as compared to control. Percentage of hydrophobicity was found to be 57 % and 41 % in Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197, respectively. Both isolates were able to show high cholesterol assimilation with a maximum of 90 % in case of Saccharomyces cerevisiae Y197 with taurocholate. They were also found to be positive for exopolysaccharide production and showed no haemolytic activity. Hence, keeping in view the results of present study, these isolates can be proposed for preparation of various probiotic food products. [ABSTRACT FROM AUTHOR]

In the food sector, the formation of biofilms as a result of microbial adherence on food-grade surfaces causes a major problem resulting in significant economic losses. Thereby, this work aimed to elaborate a biodegradable film using chitosan (CS-film) and reinforce its antiadhesion activity by incorporating pelargonium, clove, thyme, and cinnamon essential oils (EOs). Firstly, the antibacterial activity of these EOs alone and combined against four foodborne bacteria were analyzed by the microdilution method. Synergism was observed in the case of EOs combination. Secondly, the physicochemical characteristics and antiadhesion behavior of the CS-films were assessed by the contact angle method and ESEM, respectively. Results revealed that the EOs mixture treatment impacted considerably the physicochemical characteristics of the CS-film and reduced its qualitative and quantitative hydrophobicity. Moreover, the treated CS-film showed a strong antiadhesion behavior against Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with percentages of non-covered surface equal to 97.65 ± 1.43%, 98.76 ± 0.32%, 99.68 ± 0.28%, and 95.63 ± 1.32% respectively. From all these results, the CS-film treated with the mixture of EOs presents a great potential for application as surface coating and food packaging preventing microbial adhesion and thus, avoiding food contamination and spoilage. [ABSTRACT FROM AUTHOR]

Bacterial biofilm is one of the major hazards facing the food industry. Biofilm-forming ability is one of the most important virulence properties of enterococci. The genus Enterococcus includes pathogenic, spoilage, and pro-technological bacteria. The presence of enterococci in milk and dairy products is usually associated with inadequate hygiene practices. The study examined the isolates' capacity for biofilm formation and identification of the genetic determinants of its formation among 85 Enterococcus strains isolated from raw milk (n = 49) and soft-ripened cheeses made from unpasteurized milk (n = 36). E. faecalis and E. faecium were the dominant species. The obtained results showed that 41.4% isolates from milk and 50.0% isolates from cheeses were able to form biofilm. All of the isolates analyzed had at least one of the studied genes. As regards the isolates from raw milk, the most prevalent gene was the gelE (85.6%), followed by the asa1 (66.7%). None of the isolates from cheeses showed the presence of cylA and sprE. The most prevalent gene among the strains from this source was the epbC (94.4%), followed by the gelE (88.9%). In isolates from both sources, the presence of proteins from the Fsr group was noted the least frequently. Nevertheless, results showed that were no significant differences between the biofilm-producing Enterococcus spp. and non-biofilm-producing isolates in term of occurrences of tested virulence genes. The ability to produce a biofilm by enterococci isolated from raw milk or ready-to-eat products emphasizes the need for continuous monitoring of the mechanisms of microbial adhesion. [ABSTRACT FROM AUTHOR]

In order to solve the problems of low surface energy, long microbial attachment time and slow start of membrane hanging in the process of enhanced water purification, an iron carbon fiber-CF artificial water mat was constructed by combining waste iron and carbon fiber water mat. The heavily polluted surface water was used as raw water. Under the condition of stage aeration, the experiment of enhanced membrane hanging was carried out. The results showed that compared with carbon fiber artificial aquatic mat, the adhesion performance of biofilm on iron carbon fiber artificial aquatic mat was significantly improved, the hanging rate of biofilm increased from 125.1% to 133.0%, and the size of biofilm cluster structure was significantly larger. The polysaccharide, protein and protein-to-polysaccharide ratio in the extracellular polymer of biofilm changed from 53,11 mg/gVSS and 1.33 to 39, 106 mg/gVSS and 2.71 at the end of the initiation period (21 d), respectively. The enrichment and screening of Pseudomonas bacteria by iron-carbon materials improved the movement ability of bacteria and promoted the secretion of extracellular polymers by bacteria. In addition' the highly expressed functional genes of microorganisms were highly expressed in ICF, which improved the adhesion performance of microorganisms on the surface of iron-carbon fiber materials. [ABSTRACT FROM AUTHOR]

COVID-19 patients have often required prolonged endotracheal intubation, increasing the risk of developing ventilator-associated pneumonia (VAP). A preventive strategy is proposed based on an endotracheal tube (ETT) modified by the in situ deposition of eucalyptus-mediated synthesized silver nanoparticles (AgNPs). The surfaces of the modified ETT were embedded with AgNPs of approximately 28 nm and presented a nanoscale roughness. Energy dispersive X-ray spectroscopy confirmed the presence of silver on and inside the coated ETT, which exhibited excellent antimicrobial activity against Gram-positive and Gram-negative bacteria, and fungi, including multidrug-resistant clinical isolates. Inhibition of planktonic growth and microbial adhesion ranged from 99 to 99.999% without cytotoxic effects on mammalian cells. Kinetic studies showed that microbial adhesion to the coated surface was inhibited within 2 h. Cell viability in biofilms supplemented with human tracheal mucus was reduced by up to 95%. In a porcine VAP model, the AgNPs-coated ETT prevented adhesion of Pseudomonas aeruginosa and completely inhibited bacterial invasion of lung tissue. The potential antimicrobial efficacy and safety of the coated ETT were established in a randomized control trial involving 47 veterinary patients. The microbial burden was significantly lower on the surface of the AgNPs-coated ETT than on the uncoated ETT (p < 0.05). Key points: • Endotracheal tube surfaces were modified by coating with green-synthesized AgNPs • P. aeruginosa burden of endotracheal tube and lung was reduced in a porcine model • Effective antimicrobial activity and safety was demonstrated in a clinical trial [ABSTRACT FROM AUTHOR]

The formation of biofilms on the surface of dental implants and abutment materials may lead to peri-implantitis and subsequent implant failure. Recently, innovative materials such as polyether-ether-ketone (PEEK) and its modifications have been used as abutment materials. However, there is limited knowledge on microbial adhesion to PEEK materials. The aim of this in vivo study was to investigate biofilm formation on the surface of conventional (titanium and zirconia) and PEEK implant abutment materials. Split specimens of titanium, zirconia, PEEK, and modified PEEK (PEEK-BioHPP) were manufactured, mounted in individual removable acrylic upper jaw splints, and worn by 20 healthy volunteers for 24 h. The surface roughness was determined using widefield confocal microscopy. Biofilm accumulation was investigated by fluorescence microscopy and quantified by imaging software. The surface roughness of the investigated materials was <0.2 µm and showed no significant differences between the materials. Zirconia showed the lowest biofilm formation, followed by titanium, PEEK, and PEEK-BioHPP. Differences were significant (p < 0.001) between the investigated materials, except for the polyether-ether-ketones. Generally, biofilm formation was significantly higher (p < 0.05) in the posterior region of the oral cavity than in the anterior region. The results of the present study show a material-dependent susceptibility to biofilm formation. The risk of developing peri-implantitis may be reduced by a specific choice of abutment material. [ABSTRACT FROM AUTHOR]

A novel hybrid fed-batch moving-bed bioreactor (MBBR) system was developed for the treatment of refinery wastewater containing a wide range of phenol (250–1,000 mg/L) and ammonia-nitrogen (50 mg/L) using an indigenous mixed microbial culture. A hybrid system containing a native mixed microbial consortium and comprising three MBBR units connected in series and operating with a 24-day hydraulic retention time (HRT) and a recycle ratio of 1.0 was evaluated under three environmental conditions. MBBR units in the system were operated in anaerobic, anoxic, and aerobic conditions in fed-batch mode. The hybrid system proficiently removed the phenol (99%), ammonia-nitrogen (95%), and reduced chemical oxygen demand (COD) (98%) from maximum feed concentrations of 1,000, 50, and 3,077±6 mg/L , respectively. The overall NH4-N removal efficiency of the system decreased by 4.7%, and COD reduction efficiency increased by 2% while varying the feed phenol concentration from 250 to 1,000 mg/L. However, the removal rate for phenol (20.72 to 82.42 mg/L·day) and NO3-N (10.57 to 17.81 mg/L·day) increased in the anaerobic and anoxic reactor, respectively. The ammonia removal rate for the aerobic reactor decreased from 8.14 to 7.377 mg/L·day. Ultraviolet (UV)-visible spectroscopy and gas chromatography-mass spectroscopy (GC-MS) were used to identify the formation of intermediates (catechol and muconic acid) during the biotransformation of phenol. Scanning electron microscopy (SEM) analysis showed better adhesion of the mixed microbial community in the pores of the carrier media. The best fit of the modified Stover-Kincannon model confirmed that phenol and NH4-N utilization is a function of organic loading rate under steady-state conditions. The results of this investigation suggest that the newly developed hybrid system with indigenous mixed microbes can treat the heterogeneous pollutants discharged in refinery wastewater. [ABSTRACT FROM AUTHOR]

We prepared a new environment-friendly dual-function anti-fouling coating with simultaneous self-renewal and sterilization. The (Fe/TOB-PR) 20 coating displayed excellent antimicrobial properties and resistance to microbial adhesion which was attributed to the renewal of the surface and the generation of antibacterial substance (TOB) in the coating. [Display omitted] • Self-assembled Schiff-Base metal complex coatings were built from completely natural products. • The coating degradation was uniform and controlled and would not led to the accumulation of microplastics. • (Fe/TOB-PR) 20 coating exhibited excellent antimicrobial properties and resistance to microbial adhesion. • The coating could be assembled on various substrates. Marine biological fouling has caused huge economic losses and environmental problems. Therefore, it was essential to develop effectively environment-friendly biofouling resistance technology. Here, inspired by the natural module of bacterial secretions, animal and plant extracts, we synthesized Schiff based compounds through Tobramycin (TOB) from Streptomyces and Protocatechualdehyde (PR) from black fern. Furthermore, a dynamic self-renewal Schiff based metal composite coating- (Fe/TOB-PR) n was prepared via layer by layer self-assembly (LBL) method. It was proved to be a versatile coating, which could adhere to different types of substrates. Hydrolytic degradation tests showed that the degradation of the (Fe/TOB-PR) 20 coating was regular and controlled. Moreover, compared with the blank glass substrate, the antibacterial rate of (Fe/TOB-PR) 20 reached 97 % after 24 h, and the test further shows that the durability of the antibacterial performance benefits from the greater coating thickness. Such coatings displayed excellent anti-bacteria and anti-algae adhesion properties which was attributed to the renewal of the surface and the generation of antibacterial substance (TOB) in the coating. Further, the coating eventually degraded to natural micromolecule monomer, avoiding the occurrence of microplastics. It provides research ideas for fabricating environment-friendly anti-biofouling coatings. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts (QAS) commonly occur as active substances in disinfectants. QAS have the important property of coating abiotic surfaces, which prevents adhesion of microorganisms, thus inhibiting biofilm formation. In this study, a group of nine monomeric QAS, differing in the structure and length of the aliphatic chain (C12, C14, C16) and the counterion (methylcarbonate, acetate, bromide), were investigated. The study included an analysis of their action against planktonic forms as well as bacterial biofilms. The compounds were tested for their anti-adhesion properties on stainless steel, polystyrene, silicone and glass surfaces. Moreover, mutagenicity analysis and evaluation of hemolytic properties were performed. It was found that compounds with 16-carbon hydrophobic chains were the most promising against both planktonic forms and biofilms. Tested surfactants (C12, C14, C16) showed anti-adhesion activity but it was dependent on the type of the surface and strain used. The tested compounds at MIC concentrations did not cause hemolysis of sheep blood cells. The type of counterion was not as significant for the activity of the compound as the length of the hydrophobic aliphatic chain. [ABSTRACT FROM AUTHOR]

To investigate the effect of a protective coating on the surface characteristics, flexural properties, cytotoxicity, and microbial adhesion of vat-photopolymerization additive-manufacturing denture base polymers. The specimens were additively manufactured using digital light processing (DLP). Specimen surfaces were coated with the same printed resin, and mechanical polishing was used for comparison. Surface topography, arithmetical mean height (S a), and water contact angle values were measured. Furthermore, flexural strength (FS)/modulus and fractography were evaluated. Also, cytotoxicity was evaluated by an extract test. Finally, an adhesion test was used to investigate the adhesion of mixed oral bacteria to the specimens. The S a values in the polished (0.26 ± 0.08 µm) and coated (0.38 ± 0.14 µm) groups were significantly lower than in the untreated (2.21 ± 0.42 µm) and control (2.01 ± 0.37 µm) groups. The coating treatment resulted in a higher FS compared to the untreated surface (p = 0.0002). After the coating treatment, no significant differences were found in relative cell viability between the groups (p > 0.05). The quantitative results showed significantly higher bacterial adhesion in the untreated group than in the polished (p = 0.0047) and coated (p < 0.0001) groups. The surface characteristics and flexural properties were optimized by the protective coating. Also, the protective coating did not adversely affect cytocompatibility. Moreover, the coating treatment could effectively decrease oral bacteria adhering to the surfaces. Therefore, the protective coating treatment can be a less time-consuming alternative to mechanical polishing as a post-processing procedure for the digital denture. • Surface roughness was significantly decreased by the coating treatment. • The coating treatment resulted in a higher flexural strength than the untreated surface. • The protective coating did not adversely affect cytocompatibility. • The coating treatment could effectively decrease oral bacteria adhering to the surfaces. • The protective coating treatment can be a valid alternative to mechanical polishing as a post-processing procedure for an additively manufactured denture. [ABSTRACT FROM AUTHOR]