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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]

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]

[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]

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]

Investigation of the interactions between Staphylococcus aureus 209P and Kytococcus schroeteri H01 in binary biofilms revealed the sensitivity of these bacteria to the atrial natriuretic peptide (ANP) in a concentration of 6.5 × 10–10 M. In the presence of ANP, affinity of both bacteria to hexadecane decreased significantly, as was determined by MATS (microbial adhesion to solvents) experiments. Their ability to aggregate with each other and on the surface also altered in the presence of the hormone, affecting mainly the initial adhesion stage in biofilm formation. Plating of the binary communities revealed that they consisted mostly of staphylococci, while K. schroeteri constituted the minor part of the cell biomass. They, however, affected cell aggregation and the ANP effect on the community. K. schroeteri played a dualistic role, both facilitating S. aureus adhesion and acting as its antagonist in the biofilm. Moreover, in binary communities K. schroeteri was responsible for the shift of ANP action on S. aureus from neutral/stimulatory to inhibitory. [ABSTRACT FROM AUTHOR]

The inefficient extracellular electron transfer (EET) is detrimental to power generation and waste degradation in microbial fuel cells (MFCs). Herein, we report a self-supporting anode for MFCs prepared by graphitization of steamed bread slices followed by in-situ polymerization to fabricate polyaniline@N-doped macroporous carbon foam (PANI@NMCF). The natural nitrogen-containing wheat flour was fermented and carbonized to form NMCF with a high specific surface area of 818.1 m2 g−1. After the NMCF surface modified by PANI, the enhanced hydrophilicity and conductivity of the PANI@NMCF anode would facilitate microbial adhesion, biofilm formation, and electron transfer. The surface improvements enhance the EET process for high-performance MFCs, including a short startup time of 21.7 h, high maximum output power density of 1160 ± 17 mW m−2, and decolourisation efficiency of 88.6 ± 1.2% for 36 h. The chemical oxygen demand removal efficiency was about 84.6 ± 1.1% at end of the operating cycles. This work provides a good foundation for our future development of carbon-based electrode materials for energy conversion and storage devices. [Display omitted] • Polyaniline@N-doped macroporous carbon foam enhances extracellular electron transfer. • The polyaniline coating strengthens the adhesion of bacteria and mediator. • The large porosity of the N-doped carbon allows the bacteria to gradually colonize. • The assembled device obtains efficient degradation and high-efficiency power generation. [ABSTRACT FROM AUTHOR]

Purpose: Conventional orthodontic treatment with stainless steel orthodontic wires may be detrimental to oral health, as it contributes to demineralized lesions and increases adhesion and bacterial biofilm formation, which contributes to cavity development. An alternative that has been investigated to reduce the side effects of orthodontic treatment is the use of coating materials with antimicrobial nanoparticles. This study aims to evaluate the antiadherent and antibacterial properties of TiO2-coated and TiO2:Ag-coated stainless steel orthodontic wires against S. mutans bacteria. Methods: In the sol--gel method, TiO2:Ag thin films were deposited on stainless steel orthodontic wires. Coated archwires were analyzed for their antibacterial and antiadherent properties. The evaluation of Streptococcus mutans adhesion to the orthodontic wires' surface was conducted according to the type of coating used, biofilm formation assay, and measurement of the pH of the bacterial community. Results: In the microbiological test, the TiO2:Ag coatings revealed a statistically significant difference in terms of microbial adhesion and biofilm formation by Streptococcus mutans. The TiO2:Ag coating on stainless steel wire increased pH levels in the saliva environment. Conclusions: It can be concluded that antimicrobial orthodontic wires coated with silver- TiO2 nanoparticles using the sol--gel thin film are a promising choice for improving orthodontic treatment. [ABSTRACT FROM AUTHOR]

Although the adhesion of bacteria on surfaces is a widely studied process, to date, most of the works focus on a single species of microorganisms and are aimed at evaluating the antimicrobial properties of biomaterials. Here, we describe how a complex microbial community, i.e., the human gut microbiota, adheres to a surface to form stable biofilms. Two electrospun structures made of natural, i.e., gelatin, and synthetic, i.e., polycaprolactone, polymers were used to study their ability to both promote the adhesion of the human gut microbiota and support microbial growth in vitro. Due to the different wettabilities of the two surfaces, a mucin coating was also added to the structures to decouple the effect of bulk and surface properties on microbial adhesion. The developed biofilm was quantified and monitored using live/dead imaging and scanning electron microscopy. The results indicated that the electrospun gelatin structure without the mucin coating was the optimal choice for developing a 3D in vitro model of the human gut microbiota. [ABSTRACT FROM AUTHOR]

Bacterial contamination is among the major issues that occur in surgical instruments and biomedical implants. Bacterial adhesion to surgical instruments and bioimplants form a biofilm that causes microbial infection. Various surface texturing methods are being developed to change the surface properties for reducing the adhesion and colonization of bacteria. Hierarchical structure with dual-scale (micro-nano) surface roughness over materials counters bacterial growth and its spread. In this investigation, WEDM (wire electrical discharge machining) process is adopted to generate hydrophobic surface over Ti6Al4V due to its wide application in the biomedical field. The objective of this work is to evaluate the wettability and antibacterial property of fabricated curved microarray structure over Ti6Al4V. The obtained result shows that the hierarchical structure with dual-scale surface roughness increases the hydrophobicity as compared to non-hierarchical structure. E-coli was selected for bacterial adhesion investigation because this bacterial strain is very common on surgical instruments and bioimplants. The antibacterial investigation reported that colony-forming unit (CFU) of E-coli reduced from 1200 CFU for as received surface to 96 CFU for curved microarray structure. [ABSTRACT FROM AUTHOR]

Microbial adhesion to surfaces is thought to involve physicochemical interactions between the substrate and microbial cells. Understanding the physicochemical aspects involved in the adhesion phenomenon, as a critical step in biofilm formation, is essential to finding ways to prevent their formation and control biocontamination risks. The aim of this study was to investigate the relation between the adhesion behavior of 12 Escherichia coli strains isolated from food and their surface hydrophobicities using qualitative ( θ w ) and quantitative (ΔGiwi) approaches. The surface physicochemical properties of both bacterial cells and glass material were estimated through contact angle measurements. The adhesive behavior of E. coli strains on a glass surface was assessed. The results showed a good logarithmic relation between the percentage of the adhered cells and their surface hydrophobicity with the quantitative approach ΔGiwi; however, qualitative hydrophobicity ( θ w ) appeared to demonstrate no effect regarding adhesion behavior. This work lays the foundation for future studies and opens an important debate on the mechanisms underlying the adhesion behavior of E. coli strains by using the thermodynamic approach (ΔGiwi) as an important model of hydrophobicity that could explain and predict better bacterial adhesion ability. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrophobic micro-porous membrane such as polyvinylidene fluoride (PVDF) with excellent thermal-/chemical-stability and low surface energy has received extensive attention in industrial water treatment and sustainable energy conversion. However, undesirable contaminants caused by inevitable proteins or microorganisms adhesion may lead to a rapid loss of separation efficiency, which significantly deteriorate their porous structures and eventually limit their practical performance. Herein, we present a scalable approach for fabricating comb-like copolymer modified PVDF membranes (PVDF-PN@AgNPs) that prevent bacteria from proliferating on the surface and temperature-controlled release of adhered contaminants. Comb-like structured copolymers were imparted to a polydopamine (PDA)-treated PVDF membrane by Michael addition reaction, which enabled a covalent binding of comb-like structured copolymers to the membrane. Such unique structural design of grafted copolymer, containing hydrophilic side chain and temperature-responsive chain backbone, stably prevents bacteria adhesion and provides reversible surface wettability. Therefore, the resultant membranes were evaluated to prevent bacterial adhesion, high touch-killing efficiency and temperature-controlled contaminants release (~99% of protein and ~75% of bacteria). Moreover, with the collapse and stretch of grafted copolymer chain backbone, the synthetic membrane further reversibly adjusted inner micro-porous structure and surface wettability, which eventually helped to achieve variable water fluid transport efficiency. This study not only provides a feasible structural design for stably coping with the challenging of antifouling and subsequent contamination adhesion of PVDF membrane, but also potentially answers the significant gap between lab research advances and practical application, particularly in the industrial membrane field. [ABSTRACT FROM AUTHOR]

Introduction: Information regarding the adhesion of bacterial species and plaque accumulation to bracket material is limited. Adequate information is needed in order to offer patients orthodontic treatment without significantly increasing their risk of developing white spots, caries, or gingival inflammation. Aim: To determine the levels of the caries-inducing S. mutans species on metallic, self-ligating and ceramic brackets and to compare the total bacterial counts and counts of species present on these bracket materials. Materials and Methods: By means of an in-vitro study, six commercially available bracket systems {3M Gemini (A), American Ortho (B), Ormco (C), Begg (D), Ceramic (E) and Self-ligating (F)} were compared. The brackets were bonded in the cell well culture plate and the agar plates were prepared. Brain heart infusion medium including bacteria and artificial saliva was introduced to each bracket system containing 10 premolar brackets and were incubated. After 72 hours, the adherent bacteria were then detached by sonication and the Colony-Forming Units (CFU) of Streptococcus mutans were calculated on each bracket and were analysed using Statistical Package for the Social Sciences (SPSS) software version 17.0 for Windows. Results: Between the different bracket types, significant differences were found in terms of biofilm formation. The Begg brackets showed the least bacterial adhesion and the selfligating brackets showed the highest bacterial adhesion and was statistically significant among all the groups (p<0.05). Ceramic brackets also showed a higher bacterial adhesion after the self-ligating brackets. Among the three groups of metallic brackets, 3M brackets showed the least bacterial adhesion but was statistically insignificant (p>0.05). Conclusion: Different orthodontic brackets serve as different loci for biofilm formation showing that the Begg brackets are the most hygienic among all the brackets taken in this study. [ABSTRACT FROM AUTHOR]

It is necessary to enhance the barrier performance of cutoff walls in order to improve the contamination control level, especially for reconstruction or expansion of existing landfill sites. This paper presents a comprehensive laboratory investigation on the synergistic effects of microorganisms and fibers on the hydraulic conductivity of silty sand to evaluate the applicability to the field condition as an alterative barrier material. Inside the soil, the added carbon fibers not only provided good biocompatibility, but also formed spatial three-dimensional network between soil particles to improve the bacterial adhesion that eventually caused 2–3 orders of magnitude decrease in soil permeability. The resistance of the biofilm to extreme conditions was tested by permeation with solutions of different salinity and pH values, and by subjecting specimens to various hydraulic gradients and soil conditions. Despite the microbial growth inhibition occurred at these conditions, however, biofilm can largely remain intact and continue to reduce k, which due to the gradual adaptation of microorganisms to the extreme environment and the gradual recovery of their activity. Results of these tests demonstrate that biofilm treatment may be a feasible technology for creating waste containment barriers in soil. • Using biomass-fiber-soil mixture as an alternative barrier material has been attempted. • The distributed discrete fibers in soils effectively promotes microbial adhesion. • Microbial adaptability to extreme environments can still reduce hydraulic conductivity. [ABSTRACT FROM AUTHOR]

Introduction: In two-stage implants, micro-gap between the fixture and the abutment and the superstructure are the potential areas to cause peri-implantitis. The surface roughness and surface energy of the implant abutment materials play an important role in the microbial colonisation on their surface and can help the clinician to choose a better implant abutment material in terms of microbial affinity. Aim: To evaluate the effect of surface characteristics of different implant abutment materials on microbial adhesion. Materials and Methods: The comprehensive analytical experimental study was conducted at KAHER KLE VK Institute of Dental Sciences, Belagavi between Jan 2017-Dec 2017. Fortyfive (n=45) identical disc shaped specimens were fabricated using; Zirconia (Group A), Titanium alloy (Group B) and Surgical Grade Stainless Steel (Group C). The surface roughness was assessed for all test groups by Profilometer and Scanning Electron Microscope (SEM). The Surface energy was evaluated for all the test group specimens using Goniometer. Microbial adhesion and assessment were performed using sonicating and vortexing method for all the three groups using three different bacterial strains. The Colony Forming Units for all the specimens were tabulated and subjected to statistical analysis to draw the conclusions from the resultant data. The resultant data was analysed using SPSS software (Version 20). In order to collectively compare the means of the study groups pair-wise comparison of the test group was done using paired t-test with (p<0.05), and correlation between the surface parameters and CFU counts was done using Karl Pearson's correlation coefficient. Results: On pair-wise comparison of three Groups (A, B, and C) with respect to surface roughness, there were statistically significant differences in surface roughness Ra values between all the groups p<0.001. On pair-wise comparison of all the three Groups with respect to surface energy, there were statistically significant differences in Wetting Angle (WA) values between all the groups (p<0.001**) except between group B and A (p=0.15). Zirconia showed the least CFU counts for Pi and Aa though the differences were not statistically significant. Karl Pearson's correlation coefficient between surface roughness and surface energy with CFU counts showed a strongly positive correlation for all microbial species and were statistically significant p<0.001**. Conclusion: There was a strongly positive correlation of surface roughness and surface energy to CFU counts. Zirconia showed a low colonisation potential against P.intermedia and A.actinomycetemcomitans than titanium alloy and surgical grade stainless steel. [ABSTRACT FROM AUTHOR]

Introduction. An important role in the appearance of acute or chronic infections is played by bacterial biofilms that contain several bacterial species and that develop preferentially on inert surfaces, dead tissues and medical devices. Purpose. In this material we tried to make an interesting study, regarding the adhesion capacity of microbial biofilms characteristic of the oral cavity of human subjects on the surface of materials used for industrial scale manufacturing of dental implants: titanium and zirconium dioxide (Zirconia). Material and methods. For this study were used plates of Ti4 and zirconia, on which adhesion of different bacterial strains belonging to the species Enterobacter cloacae, Klebsiella oxytoca and Klebsiella pneumonia were tested. Results and discussions. A rather high microbial load was observed on both types of materials for all types of bacterial strains studied. For certain types of strains, a lower colonization was noted in the case of zirconium dioxide compared to Ti4 surfaces. Conclusions. Although Zirconia has been reported to have a lower susceptibility to bacterial adhesion, our study contradicts this aspect specified in the literature. Both titanium and zirconium dioxide are promptly colonized by existing bacteria on the teeth left in the oral cavity. [ABSTRACT FROM AUTHOR]

Understanding microbial adhesion and retention is crucial for controlling many processes, including biofilm formation, antimicrobial therapy as well as cell sorting and cell detection platforms. Cell detachment is inextricably linked to cell adhesion and retention and plays an important part in the mechanisms involved in these processes. Physico-chemical and biological forces play a crucial role in microbial adhesion interactions and altering the medium ionic strength offers a potential means for modulating these interactions. Real-time studies on the effect of ionic strength on microbial adhesion are often limited to short-term bacterial adhesion. Therefore, there is a need, not only for long-term bacterial adhesion studies, but also for similar studies focusing on eukaryotic microbes, such as yeast. Hereby, we monitored, in real-time, S. cerevisiae adhesion on gold and silica as examples of surfaces with different surface charge properties to disclose long-term adhesion, retention and detachment as a function of ionic strength using quartz crystal microbalance with dissipation monitoring. Our results show that short- and long-term cell adhesion levels in terms of mass-loading increase with increasing ionic strength, while cells dispersed in a medium of higher ionic strength experience longer retention and detachment times. The positive correlation between the cell zeta potential and ionic strength suggests that zeta potential plays a role on cell retention and detachment. These trends are similar for measurements on silica and gold, with shorter retention and detachment times for silica due to strong short-range repulsions originating from a high electron-donicity. Furthermore, the results are comparable with measurements in standard yeast culture medium, implying that the overall effect of ionic strength applies for cells in nutrient-rich and nutrient-deficient media. [ABSTRACT FROM AUTHOR]

Microbial adhesion reduction as well as platelet compatibility improvement have been suggested as the key requirements for developing blood-contacting synthetic biomaterials. Surface grafting of hydrophilic polyethylene glycol chains or alkyl chains with zwitterionic terminal ends has been proposed for reducing microbial or platelet adhesion. Nonetheless, none has been reported to incorporate both polyethylene glycol and zwitterionic terminal functionality on the same surface-grafted alkyl chain. In this investigation, a novel surface modification scheme was reported for grafting zwitterionic alkyl chains with or without polyethylene glycol as the spacer. It was noted the bacterial adhesion reduction capability on the zwitterionic modified surface was dependent upon the use of polyethylene glycol spacer or not and the strain of microbe tested. Besides, the zwitterionic modified ones all showed greater antimicrobial adhesion capability than the surface modified with polyethylene glycol alone. On the other hand, significantly reduced platelet adhesion and activation were found, but with no statistical differences noted among the polyethylene glycol-modified surface and zwitterionic ones, with or without polyethylene glycol spacer. These suggested that the use of polyethylene glycol spacer on the zwitterionic terminated surface could further enhance the antimicrobial adhesion against gram-negative bacterial while still keeping its platelet compatibility. [ABSTRACT FROM AUTHOR]

Surface contamination is a major concern in the design, fabrication, and application of biomaterials. In this work, a series of new adenine derivatives were synthesized in a three‐step method with the goal of protecting the functional materials against microbial adhesion. Initially, 9‐(chloroalkyl)‐9H‐purin‐6‐amine compounds were synthesized from adenine. Then, these compounds were reacted with potassium thiocyanate or potassium selenocyanate. In the last step, adenine derivatives incorporating a tetrazole ring were synthesized via the cycloaddition of sodium azide with thiocyano or selenocyano derivatives. The antimicrobial activity of the compounds was evaluated by using the minimal inhibitory concentration method. Furthermore, the effect of the compounds on pBR322 plasmid DNA was studied using gel electrophoretic mobility measurements. The antimicrobial assay showed that some of the synthesized compounds exerted vigorous antibacterial and antifungal activities. Further experiments indicated that seleno‐adenine derivatives have higher antimicrobial and DNA effect than other derivatives. The surfaces activated by the adenine derivative demonstrated antibacterial activity resisting bacterial attachment in order to remove dead bacteria from the surface. All results showed that some of these adenine derivatives have an antibacterial activity and the potential for further applications, for example as a smart surface coating that prevents bacterial adhesion to biomaterials. [ABSTRACT FROM AUTHOR]

Microbes have evolved sophisticated strategies to colonize biotic and abiotic surfaces. Forces play a central role in microbial cell adhesion processes, yet until recently these were not accessible to study at the molecular scale. Unlike traditional assays, atomic force microscopy (AFM) is capable to study forces in single cell surface molecules and appendages, in their biologically relevant conformation and environment. Recent AFM investigations have demonstrated that bacterial pili exhibit a variety of mechanical responses upon contact with surfaces and that cell surface adhesion proteins behave as force-sensitive switches, two phenomena that play critical roles in cell adhesion and biofilm formation. AFM has also enabled to assess the efficiency of sugars, peptides, and antibodies in blocking cell adhesion, opening up new avenues for the development of antiadhesion therapies against pathogens. [ABSTRACT FROM AUTHOR]

Creating a surface with anti- or reduced fouling characteristics can lead to a reduction in nonspecific protein adsorption as well as the bacterial adhesion and platelet adhesion/activation that occur as follows. A zwitterionic polymer that consists of both cationic and anionic functionalities have been reported as an effective material to achieve these goals, likely resulted from the strongly-adsorbed hydration layer after being immersed in the physiological environment. In this investigation, a novel beta-thiopropionate-based zwitterionic monomer, 2-ammonio-3-((3-(2-hydroxy-3-(methacryloyloxy)propoxy)-3-oxopropyl)thio)-3-methylbutanoate (DPAMA), was synthesized through a facial process. And then the hydrophobic polypropylene was surface modified with this novel zwitterionic polymer through the surface-initiated atom transfer radical polymerization technique. Surface characterization analyses have been employed to investigate the modified surface properties in each reaction stage. In vitro protein adsorption, bacterial adhesion, and platelet compatibility evaluations have shown the polyDPAMA-modified polypropylene surface has significantly reduced fouling characteristics and good hemocompatibility. Henceforth, this novel zwitterionic polyDPAMA grafting PP and the associated grafting reaction scheme have great potential for future clinical applications. [ABSTRACT FROM AUTHOR]

• The impact of antibiotic resistance on initial bacterial adhesion and biofilm formation on plastics was explored. • Single-cell adhesion spectroscopy was used to probe the initial cell adhesion on plastics. • Antibiotic resistance promoted biofilm growth on plastics by enhancing initial bacterial adhesion in antibiotic environments. The microbial biofilm formed on plastics, is ubiquitous in the environment. However, the effects of antibiotic resistance on the development of the biofilm on plastics, especially with regard to initial cell attachment, remain unclear. In this study, we investigated the initial bacterial adhesion and subsequent biofilm growth of a rifampin (Rif) resistant E. coli (RRE) and a normal gram-positive B. subtilis on a typical plastic (polyethylene, PE). The experiments were conducted in different antibiotic solutions, including Rif, sulfamethoxazole (SMX), and kanamycin (KM), with concentrations ranging from 1 to 1000 μg/L to simulate different aquatic environments. The AFM-based single-cell adhesion force determination revealed that Rif resistance strengthened the adhesion force of RRE to PE in the environment rich in Rif rather than SMX and KM. The enhanced adhesion force may be due to the higher secretion of extracellular polymeric substances (EPS), particularly proteins, by RRE in the presence of Rif compared to the other two antibiotics. In addition, the higher ATP level of RRE would facilitate the initial adhesion and subsequent biofilm growth. Transcriptome analysis of RRE separately cultured in Rif and SMX environments demonstrated a clear correlation between the expression of Rif resistance and the augmented bacterial adhesion and cellular activity. Biofilm biomass analysis confirmed the promotion effect of Rif resistance on biofilm growth when compared to non-resistant biofilms, establishing a novel association with the augmentation of microbial adhesion force. Our study highlights concerns related to the dissemination of antibiotic resistance during microbial colonization on plastic that may arise from antibiotic resistance. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding physicochemical surface characteristics of microorganisms is vital in order to reduce or prevent bacterial adhesion as an important stage of pathogenicity. These characteristics are influenced by such factors as temperature, pH, or media determining the extent of bacterial adhesion. The present study adopted a simple technique, i.e. MATS (microbial adhesion to solvents) method, to better understand microbial cell surface characteristics in four different strains, namely Staphylococcus aureus, Listeria Monocytogenes, Escherichia coli, and Pseudomonas aeruginosa. For this aim, the effect of different concentrations of human blood serum in the media of these microorganisms on physicochemical characteristics of the microorganism was evaluated. The results revealed that the microorganisms possessed different characteristics at different doses of human blood serum. Some doses of human blood serum had no effect on hydrophobicity and electron donation and reception in the microorganisms whereas some doses could cause changes in these characteristics. These findings show that care should be taken when using different concentrations of antibiotics or other compounds such as rhamnolipids. [ABSTRACT FROM AUTHOR]

Aim: To investigate the effects of combinations of several irrigants on the roughness and wettability of dentine, adhesion of Enterococcus faecalis and Candida albicans and adsorption of chlorhexidine (CHX) to the dentine. Methodology: Bovine dentine samples were prepared and their surface roughness standardized. The samples were distributed in groups (n = 10) and subjected to one of the following irrigation protocols: G1 – saline solution; G2 – sodium hypochlorite (NaOCl); G3 – NaOCl + ethylenediaminetetraacetic acid (EDTA); G4 – NaOCl + peracetic acid (PAA); G5 – NaOCl + 1‐hydroxyethylidene‐1,1‐diphosphonic acid (HEDP); G6 – NaOCl + EDTA + CHX; G7 – NaOCl + PAA + CHX; G8 – NaOCl + HEDP + CHX; and G9 – mixture of NaOCl + HEDP. After treatments, roughness and wettability were measured. In order to evaluate the adhesion of microorganisms to dentine, new dentine samples were prepared and after 2 h of contact with the microorganisms, were analysed using a confocal laser scanning microscope and the number of microorganisms adhering to the surfaces were determined. Absorption spectra were collected by attenuated total reflectance of Fourier‐transform infrared spectroscopy before and after immersion of other dentine samples in each solution of G6, G7 and G8 and in a solution of 2% CHX at various time intervals. The areas of the band associated with CHX with the peak at 1492 cm−1 were calculated between 1479 and 1500 cm−1 of the spectral range. The data obtained in all experiments were subjected to one‐way ANOVA (α < 0.05). The values of the CHX band were also subjected to one‐way repeated measures ANOVA (α < 0.05). Results: Saline solution, NaOCl, HEDP and CHX did not alter the roughness of the dentine (P > 0.05), whilst EDTA and PAA did (P < 0.05). Dentine surface wettability increased after the use of all irrigants compared to saline solution (P < 0.05), with HEDP causing the greatest increases (P < 0.05). The adhesion of E. faecalis was favoured on surfaces treated with only saline solution and NaOCl, and on samples that had decalcifying agents as the final irrigant (P < 0.05). The adhesion of C. albicans was highest on surfaces treated with only saline solution and on surfaces that had NaOCl used as the last irrigant (P < 0.05). The use of CHX as a final irrigant reduced the adhesion of both microorganisms. The roughness and wettability did not influence the adhesion of the microorganisms tested. The adsorption of CHX to the dentine was significant after 1 min of immersion of the mineralized samples in the irrigant (P < 0.05), and the use of chelating agents prior to CHX potentiated this adsorption. Conclusions: The irrigation solutions had a variable effect on the properties of dentine, on the adhesion of E. faecalis and C. albicans and the adsorption of CHX to the dentine surface. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria contamination ubiquitously occurs on high-contact surfaces in hospitals and has long been a threat to public health, inducing severe nosocomial infections that cause multiple organ dysfunction and increased hospital mortality. Recently, nanostructured surfaces with mechano-bactericidal properties have shown potential for modifying material surfaces to fight against the spread of pathogenic microorganisms without the risk of triggering antibacterial resistance. Nevertheless, these surfaces are readily contaminated by bacterial attachment or inanimate pollutants like solid dust or common fluids, which has greatly weakened their antibacterial capabilities. In this work, we discovered that the nonwetting Amorpha fruticosa leaf surfaces are equipped with mechano-bactericidal capacity by means of their randomly-arranged nanoflakes. Inspired by this discovery, we reported an artificial superhydrophobic surface with similar nanofeatures and superior antibacterial abilities. Compared to conventional bactericidal surfaces, this bioinspired antibacterial surface was synergistically accompanied by antifouling performances, which significantly prevent either initial bacterial attachment or inanimate pollutants like dust covering and fluid contaminants. Overall, the bioinspired antifouling nanoflakes surface holds promise as the design of next-generation high-touch surface modification that effectively reduces the transmission of nosocomial infections. [Display omitted] • The nonwetting and mechano-bactericidal Amorpha fruticosa leaf was first revealed. • The unique natural structures and properties inspired the design of CuO nanoflakes. • Antibacterial ability and antifouling against inanimate pollutants was achieved. • The bioinspired surface remarkably impeded the initial microbial adhesion (< 0.1%). • The preparation method was cost-effective, the surface was mechanical robustness. [ABSTRACT FROM AUTHOR]

Anode performance has been regarded as a crucial factor determining long-term stability and electricity generation of microbial fuel cells (MFCs), which restricts by the difficult extracellular electron transfer (EET) on the microbe/anode interface. Herein, inspired by biological enzyme systems, this study synthesized the biomimetic nanozymes with Fe-N-S-C active sites as the anode materials of MFCs, which was similar to the hemes of c-type cytochromes (c-Cyts) for boosting EET process. As excepted, an obviously faster start-up and a much higher power density were achieved by the MFCs equipped with Fe-N-S-C nanozymes (startup time, 3.5 d; power density, 2366 ± 34 mW m−2) than that based on traditional carbon cloth (startup time, 5.6 d; power density, 1009 ± 26 mW m−2). Such unique features of Fe-N-S-C nanozymes anode not only greatly favored the bacterial adhesion and the electroactive bacteria enrichment on the anode surface, but also efficiently facilitated the EET process between the electroactive bacteria and anode surface. This study provided a feasible strategy for designing the novel MFC anode materials from the perspective of bionic enzyme. [ABSTRACT FROM AUTHOR]

Microbial adhesion and formation of biofilms cause a serious problem in several areas including but not limited to food spoilage, industrial corrosion and nosocomial infections. These microbial biofilms pose a serious threat to human health since microbial communities in the biofilm matrix are protected with exopolymeric substances and difficult to eradicate with antibiotics. Hence, the prevention of microbial adhesion followed by biofilm formation is one of the promising strategies to prevent these consequences. The attachment of antimicrobial agents, coatings of nanomaterials and synthesis of hybrid materials are widely used approach to develop surfaces having potential to hinder bacterial adhesion and biofilm formation. In this study, epigallocatechin gallate (EGCG) is attached on p(HEMA-co-GMA) membranes to prevent the bacterial colonization. The attachment of EGCG to membranes was proved by Fourier-transform infrared spectroscopy (FT-IR). The synthesized membrane showed porous structure (SEM), and desirable swelling degree, which are ideal when it comes to the application in biotechnology and biomedicine. Furthermore, EGCG attached membrane showed significant potential to prevent the microbial colonization on the surface. The obtained results suggest that EGCG attached polymer could be used as an alternative approach to prevent the microbial colonization on the biomedical surfaces, food processing equipment as well as development of microbial resistant food packaging systems. [Display omitted] • EGCG was successfully attached on p(HEMA-co-GMA) membranes surface. • The membranes were characterized by FT-IR and SEM. • EGCG attached p(HEMA-co-GMA) membranes strongly prevented bacterial colonization. [ABSTRACT FROM AUTHOR]

Biofilms are three-dimensional structures formed as a result of microorganism's adhesion on a biotic or abiotic surface. Once a biofilm is established, it is onerous to eradicate it or kill the pathogens therein. Thus, targeting the microbial adhesion process, the initial stage of biofilm formation, is a reasonable approach to avoid challenges associated with subsequently formed biofilms. While many properties of interacting material that play significant roles in initial bacterial adhesion have been widely studied, the effect of surface stiffness on bacterial adhesion was relatively underexplored. In this study, we aimed to investigate the effect of surface stiffness on the adhesion of microbial species found in the oral cavity by employing representative oral bacteria, Streptococcus mutans and Streptococcus oralis, and the fungus, Candida albicans. We compared the adhesion behavior of these species alone or in combination toward various surface stiffness (0.06 – 3.01 MPa) by assessing the adhered and planktonic cell numbers at an early (4 h) adhesion stage under various carbon sources and the presence of conditioning film. Our data revealed that in general, a higher amount of microbial cells adhered to softer PDMS surfaces than stiffer ones, which indicates that surface stiffness plays a role in the adhesion of tested species (either single or co-cultured). This pattern was more obvious under sucrose conditions than glucose + fructose conditions. Interestingly, in monospecies, saliva coating did not alter the effect of surface stiffness on S. mutans adhesion while it diminished S. oralis and C. albicans adhesion. However, in the multispecies model, saliva coating rendered the percentage of all adhered microbes to varied PDMS not distinct. The data provide new insights into the role of surface stiffness on microbial mechanosensing and their initial adhesion behavior which may set a scientific foundation for future anti-adhesion strategies. [Display omitted] • Surface stiffness influenced the initial adhesion of oral microbes, demonstrating higher adhesion to a softer surface. • The binding patterns of individual microbes varied depending on the type of supplemented sugar. • Saliva coating did not affect S. mutans monospecies binding under sucrose-rich conditions. • Saliva coating rendered the effect of surface stiffness on all microbes' adhesion negligible when they are cocultured. [ABSTRACT FROM AUTHOR]

In the food sector, bacterial adhesion on surfaces followed by biofilm development is responsible for food contamination and spoilage, and foodborne illness, leading to considerable economic losses. Therefore, this present study aimed to elaborate a biodegradable material that inhibits bacterial adhesion and thus biofilm formation. For this purpose, chitosan-based films (CH-films) containing four different essential oils (EOs) were elaborated. The impact of these EOs on the physicochemical properties as well as the antiadhesion activity of the CH-films was evaluated. The contact angle results showed that the addition of EOs has modified significantly the physicochemical properties of the CH-film. The electron donor (γ-) and Lifshitz-Van der Waals component (γ LW ) values increased, whereas the qualitative hydrophobicity (θ w) and electron acceptor (γ+) values decreased. The analysis of bacterial adhesion using environmental scanning electron microscopy (ESEM) revealed that the CH-film containing C. zeylanicum EO exhibits the strongest antiadhesion activity against E. coli , E. hirae , and S. aureus compared to the other CH-films, with coverage rate values equal to 5.16 ± 1.13%, 2.8 ± 0.38%, and 1.52 ± 0.53%, respectively. Moreover, ESEM analysis showed that the antiadhesion effect of C. zeylanicum EO on P. aeruginosa strain was accompanied by a rupture of bacterial cells. From these findings, the CH-films incorporated with EOs could potentially be applied in the food industry to prevent microbial adhesion to surfaces and eventual biofilm formation. • The elaboration of a biodegradable film with antiadhesion activity using chitosan and essential oils. • The chemical constituents of pelargonium, thyme, cinnamon, and clove essential oils were identified. • The physicochemical properties of the chitosan-based film were affected by the incorporation of essential oils. • The chitosan-based film containing cinnamon essential oil showed strong antiadhesion activity against the tested strains. • The cell structure of P. aeruginosa was destabilized after contact with the film containing cinnamon essential oil. [ABSTRACT FROM AUTHOR]

[Display omitted] • It is possible to spontaneously create ordered micro-structures on PLA surface. • The patterns obtained are hole type. • Doping the PLA with Mg and/or CTAB, sizes between 0.5 and 20 μm can be achieved. • New surfaces could favour cell adhesion and not bacterial adhesion. The fabrication of biomaterials with structured surfaces for medical purposes is a topic of great interest. Producing topographies with certain characteristics can benefit tissue formation and/or reduce the probability of developing an infection due to the hindrance shown by certain micro-structures to microbial adhesion. This work presents a new, economically attractive way to fabricate micro-structured patterns on the surface of one of the currently most interesting bioabsorbable polymeric materials, polylactic acid (PLA). Formation of homogeneously distributed holes is presented as a function of three factors: the concentration of cetyltrimethylammonium bromide (CTAB), the presence or not of the dispersant magnesium, and the hydrophobicity of the support used in the PLA-film fabrication, silicone or glass. The size of the holes increases with the CTAB concentration: from 1 to 5 µm on silicone and 2 to 20 µm on glass. Magnesium particles make CTAB to disperse better inside the PLA matrix, provoking the irregular holes observed on glass become regular with sizes between 0.5 and 2 µm. The topographies obtained on silicone are highly stable over time, while on glass they degrade after 28 days. Consequently, it is possible to design a wide spectrum of micro-structured topographies, covering both antimicrobial and tissue integration targets. [ABSTRACT FROM AUTHOR]

There is a growing quest for an ideal biomaterial that shows appropriate cellular response and is not susceptible to microbial adhesion. In this study, commercial grade II titanium was submitted to RF/ DC plasma surface modification at 2.2 mbar, using gas mixtures of argon, nitrogen, and oxygen at proportions 4:1:2 and 4:1:3. The surfaces were physically and chemically characterized. In order to evaluate bacterial response, the surfaces were exposed to S taphylococcus epidermidis. Oxynitrided samples, although having a higher roughness as compared with untreated samples, exhibited lower bacterial growth. This observation is probably due to the formation of different crystalline phases of nitrides and oxides caused by plasma treatment. The surface with highest contact angle and highest surface tension showed lower bacterial adhesion. These results were confirmed by scanning electron microscopy. The role of nitrogen in reducing bacterial adhesion is clear when this material is compared with untreated titanium, on which only an oxide film is present. [ABSTRACT FROM AUTHOR]

The multi-drug resistance offered by Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria) against third line antibiotics can be attributed towards its ability to develop biofilm. Such process involves adhesion and quorum-sensing induced colonization leading to biomass development. The present study explored the anti-adhesion, anti-quorum sensing and anti-biofilm potential of 05 pre-standardized potent herbals. Berberis aristata (PTRC-2111-A) exhibited maximum potential in all these activities i.e. 91.3% ± 0.05% (Anti-adhesion), 96.06% ± 0.05% (Anti-Quorum sensing) and 51.3% ± 0.07% (Anti-Biofilm formation) respectively. Camellia sinensis (PTRC-31911-A) showed both anti-adhesion (84.1% ± 0.03%) and anti-quorum sensing (90.0%) potential while Holarrhena antidysenterica (PTRC-8111-A) showed only anti-quorum sensing potential as compared to standards/antibiotics. These findings were in line with the molecular docking analysis of phytoligands against Lux S and Pilin receptors. Furthermore, the pairwise correlation analysis of the tested activities with qualitative, quantitative and bioactivity functional descriptors revealed that an increased content of alkaloid, moderate content of flavonoids and decreased content of tannins supported all the three activities. In addition, nitric oxide and superoxide scavenging activity were found to be correlated with anti-quorum sensing activity. The findings indicated clearly that B. aristata (Family: Berberidaceae) and C. sinensis (Family: Theaceae) were potent herbal leads with significant therapeutic potential which further needs to be explored at pre-clinical level in the future. [ABSTRACT FROM AUTHOR]

Objectives Despite their various advantages, such as good esthetic properties, absence of mercury and adhesive bonding to teeth, modern dental composites still have some drawbacks, e.g., a relatively high rate of secondary caries on teeth filled with composite materials. Recent research suggests that microstructured biomaterials surfaces may reduce microbial adhesion to materials due to unfavorable physical material–microbe interactions. The objectives of this study were, therefore, to test the hypotheses that (i) different surface microstructures can be created on composites by a novel straightforward approach potentially suitable for clinical application and (ii) that these surface structures have a statistically significant effect on microbial adhesion properties. Methods Six different dental composites were initially tested for their suitability for microstructuring by polydimethylsiloxane (PDMS) templates. Each composite was light-cured between a glass slide and a microstructured PDMS template. The nano-hybrid composite Grandio Flow was the only tested composite with satisfying structurability, and was therefore used for the bacterial adhesion tests. Composites samples were structured with four different microstructures (flat, cubes, linear trapezoid structures, flat pyramids) and incubated for 4 h in centrifuged saliva. The bacterial adherence was then characterized by colony forming units (CFUs) and scanning electron microscopy (SEM). Results All four microstructures were successfully transferred from the PDMS templates to the composite Grandio Flow. The CFU-test as well as the quantitative analysis of the SEM images showed the lowest bacterial adhesion on the flat composite samples. The highest bacterial adhesion was observed on the composite samples with linear trapezoid structures, followed by flat pyramids and cubes. The microstructure of dental composite surfaces statistically significantly influenced the adhesion of oral bacteria. Significance Modifying the composite surface structure may be a clinically suitable approach to control the microbial adhesion and thus, to reduce the risk of secondary caries at dental composite restorations. Smaller composite surface structures may be useful for accomplishing this. [ABSTRACT FROM AUTHOR]

The effects of the presence or absence of microbial flagella and the microbial motility on the colloidal behaviors of microbial cells were quantitatively evaluated. The microbial cell attachment and detachment processes on a glass surface were observed directly using a parallel-plate flow chamber. Wild-type, flagellar paralyzed, and nonflagellated Escherichia coli strains were used as model microbial cells. In the cell attachment tests, the microbial adhesion rate in a 160 mM NaCl solution was approximately 10 times higher than that in a 10 mM solution, for all E. coli strains. The colloidal behavior of the microbial cells agreed well with the predictions of the DLVO theory. In addition, the microbial flagella and motility did not significantly affect the cell attachment, regardless of the existence of a potential barrier between the cell and the glass substratum. In the cell detachment tests, the cumulative number of microbial cells detached from the glass substratum with increasing flow rate was fit well with the Weibull distribution function. The list of strains arranged in order of increasing median drag force required to remove them was nonflagellated strain, flagellar paralyzed strain, and wild-type strain. These results indicated that the flagella and the flagellar motility inhibited the cell detachment from the glass substratum. Furthermore, a large external force would likely be required to inhibit the microbial adhesion in the early stage of the biofilm formation. [ABSTRACT FROM AUTHOR]

The exploitation of macroalgal biomass could provide novel environment-friendly molecules to prevent bacterial biofilm formation. Crude extracts, or polysaccharides, from the DNA-barcoded macroalgae Chaetomorpha aerea (Chlorophyta), and Agardhiella subulata and Hypnea cornuta (Rhodophyta) collected from the coastal brackish Lake of Ganzirri (Italy) were evaluated for their effects on biofilm formation of Listonella anguillarum, Vibrio harveyi, V. parahaemolyticus and Photobacterium damselae subsp. piscicida. All bacterial strains were able to produce biofilm on polystyrene surfaces at different extents. Without exerting antibacterial activity, the crude polysaccharides showed dose-dependent inhibitory activity on the biofilm formation. At the highest concentration (400 μg/ml), the strongest reduction of biofilm formation was observed in the presence of C. aerea and A. subulata extracts against V. harveyi (59 and 53%, respectively) , followed by the H. cornuta extract against P. piscicida (52%) and V. parahaemolyticus (28%). The extract from A. subulata was also active against the biofilm formation of P. piscicida (48%) and L. anguillarum (33%). As resulted by the surface coating assay and the microbial adhesion onto hydrocarbons, the algal extracts were able to inhibit the adhesion of pathogens and modify their cell-surface properties and hydrophobicity. Moreover, all the extracts possessed high emulsifying activity (E 24 up to 70%) and stabilizing capacity. Based on two different in vivo assays, using Artemia salina and Danio rerio, all the extracts showed no potential toxicity for aquaculture application. Our results suggest that the antibiofilm activity of algal extracts is related to the inhibition of the early bacterial adhesion. Consequently, these non-toxic and biodegradable polysaccharides, with surfactant and antiadhesive properties, could be proposed to prevent biofilms in aquaculture. • Seaweeds provide environment-friendly molecules to prevent biofilms in aquaculture. • Crude extracts from red and green algae reduce biofilm formation of pathogens. • Polysaccharides prevent the initial adherence acting as surfactants and antiadhesives. • Algal extracts showed no in vivo toxicity against Artemia salina and Danio rerio. • Our extracts could be proposed to develop antibiofilm measures in aquaculture. [ABSTRACT FROM AUTHOR]

Abstract: The bacterial adhesion can be controlled (inhibit or promote) by different material surface characteristics like surface roughness, on which we concentrate in our study. Four different glass surfaces were prepared by polishing the glass plates with different gradations. The corresponding surface roughness was controlled by atomic force microscope and profilometer. For experiments we have used one Gram-positive bacterium (Staphylococcus aureus) and two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). The rate of adhered bacteria on glass surfaces was determined spectrophotometrically. The results showed that the rate of adhered bacteria increases with increasing surface roughness. The increased adhesion of bacteria on more rough surfaces is the interplay between the increasing effective surface and increasing number of defects on the surface. In order to keep all parameters under control we have also measured the surface charge density and hydrophobicity of bacteria and glass surfaces as well. [Copyright &y& Elsevier]

The ability of silver nanoparticles to modify the thermodynamic characteristics of stainless steel surfaces in order to reduce the adhesion process and thereby inhibit biofilm formation was evaluated. We observed that silver nanoparticles were able to decrease the contact angle of stainless steel from 73.20° when conditioned with water to 12.10° making the surface more hydrophilic. Thus, the thermodynamics of adhesion for all the evaluated bacteria was more unfavorable when the stainless steel surfaces were conditioned with the nanoparticles. Regarding the bacteria,Staphylococcus aureuswas the most hydrophilic (p < 0.05) followed forEscherichia coli,Pseudomonas aeruginosa, andListeria innocua. Thereby, the silver nanoparticles demonstrated efficiency in inhibiting theoretical adhesion by altering the surface hydrophobicity that can potentially hamper cellular adhesion and prevent biofilm formation. [ABSTRACT FROM AUTHOR]

Biofilms, surface-bound communities of microbes, are economically and medically important due to their pathogenic and obstructive properties. Among the numerous strategies to prevent bacterial adhesion and subsequent biofilm formation, surface topography was recently proposed as a highly nonspecific method that does not rely on small-molecule antibacterial compounds, which promote resistance. Here, we provide a detailed investigation of how the introduction of submicrometer crevices to a surface affects attachment of Escherichia coli. These crevices reduce substrate surface area available to the cell body but increase overall surface area. We have found that, during the first 2 h, adhesion to topographic surfaces is significantly reduced compared with flat controls, but this behavior abruptly reverses to significantly increased adhesion at longer exposures. We show that this reversal coincides with bacterially induced wetting transitions and that flagellar filaments aid in adhesion to these wetted topographic surfaces. We demonstrate that flagella are able to reach into crevices, access additional surface area, and produce a dense, fibrous network. Mutants lacking flagella show comparatively reduced adhesion. By varying substrate crevice sizes, we determine the conditions under which having flagella is most advantageous for adhesion. These findings strongly indicate that, in addition to their role in swimming motility, flagella are involved in attachment and can furthermore act as structural elements, enabling bacteria to overcome unfavorable surface topographies. This work contributes insights for the future design of antifouling surfaces and for improved understanding of bacterial behavior in native, structured environments. [ABSTRACT FROM AUTHOR]

The first step of infection is the adhesion of pathogens to target cells. This feature not only allows them to penetrate and deploy offensive strategies to initiate colonization, but to contribute to their protection and preservation against both the immunological and mechanical defense mechanisms of the host. This process is conducted largely by the interaction of lectins, which are proteins of non-immune origin with the ability to recognize and bind carbohydrates. This mechanism has been reported for many microorganisms such as bacteria and viruses. In the particular case of Pasteurella multocida, which is a Gram-negative, opportunistic pathogen bacterium that starts the infection in the respiratory epithelium of many animals, lectin substances have been described on its surface, such as type IV fimbria, and carbohydrates such as lipopolysaccharide or the capsule that recognizes carbohydrates and lectins, respectively, on the surface of epithelial cells of the trachea, a circumstance that allows it to adhere and escape the mucociliary effect. Seeing as, to most of these microorganisms--including P. multocida--the decreased susceptibility to antibacterial agents and the effectiveness of vaccines is evident, new therapeutic and prophylactic tactics have been sought in order to interrupt pathogenic infection by blocking the carbohydrate-lectin bond by competition, where the union of the microorganism to the tissue and, therefore, the infection, is diminished. [ABSTRACT FROM AUTHOR]

The initial microorganism adhesion on substrate is an important step for the biofilm formation. The surface properties of the stainless steel and B. cereus were characterized by the sessile drop technique. Moreover, the physicochemical properties of surface adhesion and the impact of bio adhesion to the stainless steel were determined at different time of contact (2, 4, 7, 9 and 24 h). The results showed that the strain was hydrophilic (Giwi = 3.37 mJ/m), whereas the substratum has hydrophobic character (Giwi = −57.6 mJ/m). Stainless steel surface presents a weak electron-donor character (γ = 4.1 mJ/m) conversely to B. cereus that presents an important parameter (γ = 31.6 mJ/m). The bio adhesion was investigated at different time of contact. The data analysis after 2 h, confirmed the adhesion of B. cereus with an amount of 10 cfu/cm which increased to 1.210 cfu/cm after 24 h. Interestingly, despite the difference of hydropohbicity, the interaction between B. cereus and substratum was favored by the thermodynamic aspect of adhesion (ΔG < 0). Interestingly, the study of the effect of B. cereus adhesion on the stainless steel has revealed that, the substratum becomes hydrophilic (θ° = 41.3, ΔGiwi = 39.6 mJ/m) and highly electron donor (Γ = 52.9 mJ/m) after 2 h of bio adhesion. [ABSTRACT FROM AUTHOR]

Microbial biofouling is important in a variety of applications including reverse osmosis membranes and in-situ bioremediation. The initial microbial adhesion plays the key role in microbial biofouling on abiotic surfaces, which can be explained in terms of microbial surface properties. This research investigated the interactions of three indigenous bacteria with the porous medium of silica sand and their corresponding initial attachment. Traditional and extended DLVO forces were calculated based on independently measured bacterial and medium surface thermodynamic properties and were related to bacterial attachment observations. Lifshitz-van der Waals, electrostatic and Lewis acid/base forces were found to be strongly dependent on the separation distance between bacteria and the medium surface. It was concluded that the electrostatic force served as the barrier preventing the bacterial strains from getting close to the medium. Once the bacterial strains overcame the barrier with the aid of hydrodynamic forces, Lifshitz-van der Waals force and electrostatic force dropped while Lewis acid/base force increased with the decrease of separation distance. Consequently, Lewis acid/base force became the dominating force controlling bacterial adhesion. [ABSTRACT FROM AUTHOR]

The risk of groundwater contamination by microbial pathogens is linked to their survival in the subsurface. Although there is a large body of literature on the inactivation behavior of suspended (planktonic) microorganisms, little is known about the inactivation of bacteria when attached to sand grain surfaces in groundwater aquifers. The main goal of this study was to develop a fluorescence-based experimental technique for evaluating the extent of inactivation over time of bacteria adhered onto a surface in an aqueous environment. Key features of the developed technique are as follows: (i) attached cells do not need to be removed from the surface of interest for quantification, (ii) bacterial inactivation can be examined in real-time for prolonged time periods, and (iii) the system remains undisturbed (i.e., the aqueous environment is unchanged) during the assay. A negatively or positively charged substrate (i.e., bare or coated glass slide) was mounted in a parallel-plate flow cell, bacteria were allowed to attach onto the substrate, and the loss of bacterial membrane integrity and respiratory activity were investigated as a function of time by fluorescence microscopy using Live/Dead BacLight and BacLight RedoxSensor CTC (5-cyano-2,3-ditolyl tetrazolium chloride) viability assays. These two different measures of bacterial inactivation result in comparable trends in bacterial inactivation, confirming the validity of the experimental technique. The results of this work show that the developed technique is sensitive enough to distinguish between the inactivation kinetics of different representative bacteria attached to either a negatively charged (bare glass) surface or a positively charged (coated glass) surface. Hence, the technique can be used to characterize bacterial inactivation kinetics when attached to environmentally relevant surfaces over a broad range of groundwater chemistries. [ABSTRACT FROM AUTHOR]

Abstract: Acid–base (AB) interactions play the most important role in bacterial attachment to surfaces and can be quantified based on electron donor/electron acceptor data from contact angle measurement (CAM) according to the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory. It follows that the XDLVO theory could fail to explain attachment numbers if differences in AB interactions between strains are not apparent by CAM. This study aimed to investigate the validity of the above assumptions by comparing empirical data on attachment of six bacterial strains (three strains of Campylobacter jejuni and three strains of Salmonella) to stainless steel and XDLVO theory predictions. A significant difference (P <0.05) in AB interactions, apparent by CAM, between C. jejuni strains allowed prediction of attachment of this species by the XDLVO theory. However, the theory failed to explain the attachment numbers for Salmonella due to similar AB interactions, as established by CAM, between the three Salmonella strains. Qualitative analysis of AB interactions by microbial adhesion to solvents (MATS) revealed a significant difference (P <0.05) in electron donor property between the three Salmonella strains suggesting that these strains may differ with respect to AB interactions. No significant correlation with respect to electron donor property (P =0.502, r 2 =12%) was apparent between CAM and MATS. These data suggest that CAM may not always reflect exactly AB interactions and that the difference in the outcomes from MATS and CAM should be considered when the XDLVO theory is used to predict bacterial attachment to surfaces. [Copyright &y& Elsevier]

Abstract: Adhesion behavior of Escherichia coli from its suspension onto stainless steel (type 304) surface was studied, focusing on the effects of initial cell concentration of suspension, suspending medium, and roughness of stainless steel surface. The results demonstrated that the adhesion of E. coli was significantly enhanced by the cell concentration of contaminants. The adhesion was observed even in short contact periods of time, but it increased and reached a plateau within 3–4h. The plateau value of surface cell density was roughly proportional to the cell concentration of the suspension. Rinsing experiments indicated that a relatively high percentage of cells were found to be irreversibly attached on the surface when peptone saline was used as a suspending medium. The adherent cells were however shown to be quite vulnerable to removal with water as a rinsing medium. Moreover surface roughness was found to affect the removability of adherent cells. [Copyright &y& Elsevier]

The presence and maturity of the salivary pellicle influences microbial adhesion and its tenacity in the oral cavity, posing a challenge to different plaque-control systems. Some plaque-control systems rely on surface-tension forces arising from passing microbubbles sprayed over the pellicle. Passage of such bubbles is accompanied by a high fluid flow, but systematic studies are lacking on the contribution of fluid flow vs. microbubbles towards plaque removal. Therefore, the aim of this study was to determine the detachment efficacy of laminar fluid flow (wall shear rates 11,000–16,000 s−1), with and without microbubbles, towards the detachment of Actinomyces naeslundii T14V-J1 and Streptococcus oralis J22, and their coadhering aggregates, from salivary pellicles formed over 2 h or 16 h from reconstituted human whole saliva. Microbubbles in a fluid flow were more efficient at inducing single bacterial detachment, resulting in almost complete (97%) removal for S. oralis J22 and a 15-fold increase in A. naeslundii T14V-J1 removal as compared to the detachment caused by fluid flow alone. A. naeslundii was more difficult to remove and apparently formed the strongest bonds with high-molecular-weight proteins in 16-h pellicles. The detachment of coaggregates after 2 min left a substantial amount of adhered bacterial mass, including more than 60% of singly attached A. naeslundii on the pellicle surface, providing nucleation sites for the de novo adhesion of coadhering streptococci. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate whether hygienic characteristics of stainless steel used in the food industry could be improved by smoothing surface roughness (Ra) from Ra 0.9–0.01 μm. The adherence of Pseudomonas sp., Listeria monocytogenes and Candida lipolytica, to stainless steel was not affected by surface roughness ranging from grit 4000 polished stainless steel (Ra<0.01) to ground stainless steel (Ra 0.9). Neither adhesion of Ps. aeruginosa nor its removal by an alkaline commercial cleaner in a flow system was affected by surface roughness. Pitting corrosion resistance was evaluated in a commercial disinfectant and in 1 M NaCl. Electropolished and grit 4000-polished steel proved more corrosion resistant as opposed to grit 80- and 120- polished surfaces. In conclusion, the surface finish did not influence bacterial attachment, colonziation or removal, but is an important parameter for the corrosion resistance of the surface. [Copyright &y& Elsevier]

Microbial adhesion to oral splints may lead to oral diseases such as candidiasis, periodontitis or caries. The present in vitro study aimed to assess the effect of novel computer-aided design/computer-aided manufacturing (CAD/CAM) and conventional manufacturing on Candida albicans and Streptococcus mutans adhesion to oral splint resins. Standardized specimens of four 3D-printed, two milled, one thermoformed and one pressed splint resin were assessed for surface roughness by widefield confocal microscopy and for surface free energy by contact angle measurements. Specimens were incubated with C. albicans or S. mutans for two hours; a luminometric ATP assay was performed for the quantification of fungal and bacterial adhesion. Both one-way ANOVA with Tukey post hoc testing and Pearson correlation analysis were performed (p < 0.05) in order to relate manufacturing methods, surface roughness and surface free energy to microbial adhesion. Three-dimensional printing and milling were associated with increased adhesion of C. albicans compared to conventional thermoforming and pressing, while the S. mutans adhesion was not affected. Surface roughness and surface free energy showed no significant correlation with microbial adhesion. Increased fungal adhesion to oral splints manufactured by 3D printing or milling may be relevant for medically compromised patients with an enhanced risk for developing candidiasis. [ABSTRACT FROM AUTHOR]

Assesses cell surface charge and hydrophobicity and adhesion to polystyrene, glass, and barley for wild-type Rhodosporidium toruloides and attachment-minus mutants. Decrease in hydrophobicity and adhesiveness of wild-type R. toruloides from mid-log to late stationary phase; Role of localized, positive charge in mediating attachment.

Microbes have remarkable capabilities to attach to the surface of implanted medical devices and form biofilms that adversely impact device function and increase the risk of multidrug-resistant infections. The physicochemical properties of biomaterials have long been known to play an important role in biofilm formation. More recently, a series of discoveries in the natural world have stimulated great interest in the use of 3D surface topography to engineer antifouling materials that resist bacterial colonization. There is also increasing evidence that some medical device surface topographies, such as those designed for tissue integration, may unintentionally promote microbial attachment. Despite a number of reviews on surface topography and biofilm control, there is a missing link between how bacteria sense and respond to 3D surface topographies and the rational design of antifouling materials. Motivated by this gap, we present a review of how bacteria interact with surface topographies, and what can be learned from current laboratory studies of microbial adhesion and biofilm formation on specific topographic features and medical devices. We also address specific biocompatibility considerations and discuss how to improve the assessment of the anti-biofilm performance of topographic surfaces. We conclude that 3D surface topography, whether intended or unintended, is an important consideration in the rational design of safe medical devices. Future research on next-generation smart antifouling materials could benefit from a greater focus on translation to real-world applications. Image 1 [ABSTRACT FROM AUTHOR]

• Surface-active substances were synthesized by co-culture of Rhodococcus erythropolis (SASI). • SASI had higher biological activity compared with SAS synthesized by monoculture. • Minimum inhibitory concentrations of SASI decreased in 4–32 times comparable with SAS. • Microbial cells adhesion to surfaces treated with SASI was 10–32 % (32–87 % after SAS). • Destruction of biofilms by SASI increased in 1.3–2.0 times comparable with SAS. Surface-active substances synthesized by Rhodococcus erythropolis ІMВ Ас-5017 during co-cultivation with inducing bacteria either Bacillus subtilis BT-2 or Escherichia coli ІЕM-1 (SASI) had the higher antimicrobial and antiadhesive activities in comparison with surface-active substances synthesized in the medium without cells of inducing bacteria (SAS). Minimum inhibitory concentrations of SASI ranged from 3 to12 μg/mL and were in 4–32 times lower than the same parameter for SAS. Treatment of abiotic surfaces (ceramic, steel, and glass) with SASI decreased adhesion of bacteria Staphylococcus aureus BMC-1 or yeasts Candida albicans D-6 to the level of 10–32 % in comparison with 32–87 % after treatment of surfaces with SAS. Destruction of bacterial and yeast biofilms treated with SASI was in the range from 40 to 94 %, while it was 32–65 % in the case when SAS was used. Increasing of biological activity of surface-active substances synthesized by R. erythropolis in co-culture with inducing bacteria E. coli or B. subtilis was shown for the first time. [ABSTRACT FROM AUTHOR]