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A novel procedure for the quantitative analysis of biofilm formation by bacteria and yeasts, the Plate-hanging method, was developed. In this system, various polymer disks were hung from the lid of a 6-well plate, immersed in a cell suspension, and moderately shaken (70 rpm). In order to verify the validity of the procedure, the effects of the solid surface hydrophobicity of the test disks and the cell surface hydrophobicities of microorganisms on biofilm formation were investigated. Biofilm formation of bacteria and yeasts on the solid surface strongly depended on hydrophobic interactions between the solid surface and the cell surface. A positive correlation between the hydrophobic properties of substratum and cell surfaces was observed. On the other hand, hydrophilic yeasts preferentially adsorbed onto relatively hydrophilic surfaces. Moreover, the plate-hanging method coupled with the periodic exchange of the liquid medium enabled the quantification of long-term biofilm growth., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest associated with this manuscript. The authors have no conflicts of interest directly relevant to the content of this article., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Skin is the largest protective tissue of the body and is at risk of damage. Hence, the design and development of wound dressing materials is key for tissue repair and regeneration. Although silk fibroin is a known biopolymer in tissue engineering, its degradation rate is not correlated with wound closure rate. To address this disadvantage, we mimicked the hierarchical structure of skin and also provided antibacterial properties; a hydrogel with globular structure consisting of silk fibroin, pluronic F127, and curcumin was developed. In this regard, the effect of pluronic and curcumin on the structural and mechanical properties of the hydrogel was studied. The results showed that curcumin affected the particle size, crystallinity, and ultimate elongation of the hydrogels. In vitro assays confirmed that the hydrogel containing curcumin is not cytotoxic while the diffused curcumin and pluronic provided a considerable bactericidal property against Methicillin-resistant Staphylococcus aureus. Interestingly, presence of pluronic caused more than a 99% reduction in planktonic and adherent bacteria in the curcumin-free hydrogel groups. Moreover, curcumin improved this number further and inhibited bacteria adhesion to prevent biofilm formation. Overall, the developed hydrogel showed the potential to be used for skin tissue regeneration. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the surface roughness and contact angle of composite resins produced by CAD/CAM milling and three-dimensional (3D) printing for permanent restorations as well as the adhesion of S. mutans and S. sanguinis bacteria to these composites. Three CAD/CAM milling composite resins (Vita Enamic-VE, Cerasmart-CE, Lava Ultimate-LU) and three 3D printing resins (Varseo Smile Crown plus-VSC, Saremco print Crowntech-SPC, Formlabs 3B Permanent crown-FLP) were selected. Twenty samples were prepared for each group. Using a contact profilometer, the surface roughness was determined, and an optical goniometer was used to quantify the contact angle. To evaluate the bacterial adhesion, composite specimens were immersed in mucin containing artificial saliva. All samples were incubated for 24 h at 37°C in 5% CO2. CFUs were determined by counting colonies after the incubation period. Surface roughness values of test samples were the highest in the Group VSC [0.46 (0.14) µm], whereas the lowest values were found in the Group LU [0.23 (0.05) µm]. There was no statistically significant difference between the groups in contact angle values (p > 0.05). The S. mutans adhesion extent on the Group SPC was statistically higher compared to all other materials with p < 0.05. For S. sanguinis, the lowest bacterial adhesion value was recorded in Group CE (3.00 × 104 CFU/ml) and statistically significant differences were found with Group VE and VSC (p < 0.05). Different digital manufacturing techniques and material compositions can affect the surface roughnesses of composite resins. All composite resin samples have hydrophobic characteristics. Microbial adhesion of the tested composite resins may be varied depending on the bacterial species. S. mutans showed much more adhesion to these materials than S. sanguinis. [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]

Slippery surfaces (i.e., surfaces that display high liquid droplet mobility) are receiving significant attention due to their biofluidic applications. Non‐textured, all‐solid, slippery hydrophilic (SLIC) surfaces are an emerging class of rare and counter‐intuitive surfaces. In this work, the interactions of blood and bacteria with SLIC surfaces are investigated. The SLIC surfaces demonstrate significantly lower platelet and leukocyte adhesion (≈97.2% decrease in surface coverage), and correspondingly low platelet activation, as well as significantly lower bacterial adhesion (≈99.7% decrease in surface coverage of live Escherichia Coli and ≈99.6% decrease in surface coverage of live Staphylococcus Aureus) and proliferation compared to untreated silicon substrates, indicating their potential for practical biomedical applications. The study envisions that the SLIC surfaces will pave the path to improved biomedical devices with favorable blood and bacteria interactions. [ABSTRACT FROM AUTHOR]

Purpose This study aimed to evaluate the effect of nylon versus heat‑cure acrylic resin on microbial adhesion of a closed hollowed obturator. Patients and methods Twelve male patients with a unilaterally acquired maxillary defect (Aramany Class IV) were chosen from the outpatient clinic of the Prosthodontics Department at the Faculty of Dentistry, Sinai University (Kantara branch). These patients were divided into two equal groups: group I was provided with an obturator made of heat‑cured acrylic resin (P.M.M.A.‑Vertex), while group II received an obturator made of thermopress resin (nylon breflex, 2nd edition). Each group underwent microbial evaluation through follow‑up recall visits at 2 and 4 weeks. The results were recorded, tabulated, and subjected to statistical analysis. Results There is a significant difference between group I and group II. The conventional acrylic resin group showed higher bacterial adhesion than the nylon. Conclusion Within the limitations of the study, a closed hollow bulb constructed with thermopress resin exhibits reduced bacterial colonization when compared to heat‑cured acrylic resin. [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]

Objectives: This paper presents a systematic review and meta-analysis of the effect of different finishing and polishing (F/P) systems on surface roughness (SR) and microbial adhesion to bulk fill (BF) composites. Materials and Methods: An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Only in vitro studies that evaluated SR and microbial adhesion to BF composites were included. The included studies were individually evaluated for the risk of bias following predetermined criteria. A meta-analysis of the reviewed studies was conducted to compare the SR values of both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill with and without F/P using the Comprehensive Meta-Analysis software. Results: A total of 12 studies fulfilled the inclusion criteria. The meta-analysis showed no significant difference between Filtek Bulk Fill and Tetric EvoCeram Bulk Fill without F/P or after F/P using multi-step systems. Different F/P systems affected the SR values, on the other hand, did not affect microbial adhesion values. Conclusion: Both Filtek Bulk Fill and Tetric EvoCeram Bulk Fill had comparable roughness results. Multi-step systems may be preferable for F/P of BF composites. [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]

The properties of intestinal bacteria/probiotics, such as cell surface hydrophobicity (CSH), auto-aggregation, and biofilm formation ability, play an important role in shaping the relationship between the bacteria and the host. The current study aimed to investigate the cell surface properties of fish intestinal bacteria and probiotics. Microbial adhesion to hydrocarbons was tested according to Kos and coauthors. The aggregation abilities of the investigated strains were studied as described by Collado and coauthors. The ability of bacterial isolates to form a biofilm was determined by performing a qualitative analysis using crystal violet staining based on the attachment of bacteria to polystyrene. These studies prove that bacterial cell surface hydrophobicity (CSH) is associated with the growth medium, and the effect of the growth medium on CSH is species-specific and likely also strain-specific. Isolates of intestinal lactobacilli from fish (Salmo ischchan) differed from isolates of non-fish/shrimp origin in the relationship between auto-aggregation and biofilm formation. Average CSH levels for fish lactobacilli and E. coli might were lower compared to those of non-fish origin, which may affect the efficiency of non-fish probiotics use in fisheries due to the peculiarities of the hosts' aquatic lifestyles. [ABSTRACT FROM AUTHOR]

Bacterial keratitis is a risk associated with the use of contact lenses for cosmetic purposes or vision correction. In this in vitro experimental study, we examined the ability of the ocular pathogen Serratia marcescens to adhere to monthly or biweekly replacement contact lenses. We performed quantitative adhesion assays to evaluate the adherence of S. marcescens to seven contact lens materials: comfilcon A, senofilcon A, omafilcon B, fanfilcon A, balafilcon A, senofilcon C, and lehfilcon A. Lehfilcon A is a newly marketed silicon hydrogel contact lens with a surface modification of poly-(2-methacryloyloxyethyl phosphorylcholine) (PMPC). PMPC has previously been demonstrated to be an effective anti-biofouling treatment for numerous surfaces. We observed low S. marcescens adherence to lehfilcon A compared to other materials. We demonstrate the use of the fluorescent dye 5(6)-Carboxytetramethylrhodamine succinimidyl ester to covalently stain live cells prior to material adhesion studies. [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]

Biofilms are highly resistant to external forces, especially chemicals. Hence, alternative control strategies, like antimicrobial substances, are forced. Antimicrobial surfaces can inhibit and reduce microbial adhesion to surfaces, preventing biofilm formation. Thus, this research aimed to investigate the bacterial attachment and biofilm formation on different sealants and stainless steel (SS) surfaces with or without antimicrobials on two Gram-positive biofilm forming bacterial strains. Antimicrobial surfaces were either incorporated or coated with anti-microbial, -fungal or/and bactericidal agents. Attachment (after 3 h) and early-stage biofilm formation (after 48 h) of Staphylococcus capitis (S. capitis) and Microbacterium lacticum (M. lacticum) onto different surfaces were assessed using the plate count method. In general, bacterial adhesion on sealants was lower compared to adhesion on SS, for surfaces with and without antimicrobials. Antimicrobial coatings on SS surfaces played a role in reducing early-stage biofilm formation for S. capitis, however, no effects were observed for M. lacticum. S. capitis adhesion and biofilm formation were reduced by 8% and 25%, respectively, on SS coated with an antimicrobial substance (SS_4_M), compared to the same surface without the antimicrobial coating (SS_4_control). Incorporation of both antifungicidal and bactericidal agents (S_5_FB) significantly reduced (p ≤ 0.05) early-stage biofilm formation of M. lacticum, compared to the other sealants incoportating either solely antifungal agents (S_2_F) or no active compound (S_control). Furthermore, the thickness of the coating layer correlated weakly with the antimicrobial effect. Hence, equipment manufacturers and food producers should carefully select antimicrobial surfaces as their effects on bacterial adhesion and early-stage biofilm formation depend on the active agent and bacterial species. [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]

Purpose: To compare the flexural properties and the adhesion of Lactobacillus salivarius (LS), Streptococcus mutans (SM), and Candida albicans (CA) on heat-polymerized (CV), CAD-CAM milled (CAD), or 3D-printed (3D) Poly (methylmethacrylate) (PMMA). Methods: Ultimate Flexural Strength (UFS), Flexural Strain (FS) (%) at Flexural Strength, and Flexural Modulus (FM) of specimens (65.0×10.0×3.3 mm) from each PMMA group (n=6) were calculated by using the 3-point bending test. The surface roughness profiles (R) were measured before and after polishing with a contact profilometer. LS, SM, and CA adhesion on PMMA specimens (n=18) (10 mm in diameter, 3 mm in height) was assessed after 90 minutes and 16 hours by using scanning electron microscopy. The Kruskal-Wallis test with post hoc analysis was performed to compare the groups (alpha=0.05). Results: Mean UFS values were 80.79±7.64 MPa for CV, 110.23±5.03 MPa for CAD, and 87.34±6.39 MPa for 3D. Mean FS values were 4.37±1.04% for CV, 4.71±0.62% for CAD, and 6.19±0.13 % for 3D. Mean FM values were 2542±301 MPa for CV, 3435±346 MPa for CAD, and 2371±197 MPa for 3D. CAD had the lowest average R value (0.29±0.16 µm) before polishing, and bacterial adhesion after 90 minutes of incubation. R value and microbial adhesion were not different amongst groups after polishing and 16 hours of incubation, respectively. Conclusion: The CAD group displayed the best flexural properties, except for FS, the lowest roughness before polishing and bacterial adhesion after 90 minutes of incubation. All tested PMMAs had similar surface roughness after polishing, and microbial adhesion after 16 hours of incubation. [ABSTRACT FROM AUTHOR]

This review deals with microbial adhesion to metal-based surfaces and the subsequent biofilm formation, showing that both processes are a serious problem in the food industry, where pathogenic microorganisms released from the biofilm structure may pollute food and related material during their production. Biofilm exhibits an increased resistance toward sanitizers and disinfectants, which complicates the removal or inactivation of microorganisms in these products. In the existing traditional techniques and modern approaches for clean-in-place, electrochemical biofilm control offers promising technology, where surface properties or the reactions taking place on the surface are controlled to delay or prevent cell attachment or to remove microbial cells from the surface. In this overview, biofilm characterization, the classification of bacteria-forming biofilms, the influence of environmental conditions for bacterial attachment to material surfaces, and the evaluation of the role of biofilm morphology are described in detail. Health aspects, biofilm control methods in the food industry, and conventional approaches to biofilm removal are included as well, in order to consider the possibilities and limitations of various electrochemical approaches to biofilm control with respect to potential applications in the food industry. [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]

• Bacterial adhesion to the surface of dental materials play a significant role in infections. • The factors that govern microbial attachment involves different types of physical-chemical interactions and biological processes. • Studying bacterial adhesion makes it possible to understand the mechanisms involved in attachment and helps in the search for technologies that promote antibacterial surfaces. Bacterial attachment to biomaterials is of great interest to the medical and dental field due to its impact on dental implants, dental prostheses, and others, leading to the need to introduce methods for biofilm control and mitigation of infections. Biofilm adhesion is a multifactorial process and involves characteristics relevant to the bacterial cell as well as biological, chemical, and physical properties relative to the surface of biomaterials. Bacteria encountered different environmental conditions during their growth and developed interspecies communication strategies, as well as various mechanisms to detect the environment and facilitate survival, such as chemical sensors or physical detection mechanisms. However, the factors that govern microbial attachment to surfaces are not yet fully understood. In order to understand how bacteria interact with surfaces, as well as to characterize the physical-chemical properties of bacteria adhesins, and to determine their interrelation with the adhesion to the substrate, in recent years new techniques of atomic force microscopy (AFM) have been developed and helped by providing quantitative results. Thus, the purpose of this review is to gather current studies about the factors that regulate microbial adhesion to surfaces in order to offer a guide to studies to obtain technologies that provide an antimicrobial surface. [ABSTRACT FROM AUTHOR]

Bacterial keratitis is a risk associated with the use of contact lenses for cosmetic purposes or vision correction. In this in vitro experimental study, we examined the ability of the ocular pathogen Serratia marcescens to adhere to monthly or biweekly replacement contact lenses. We performed quantitative adhesion assays to evaluate the adherence of S. marcescens to seven contact lens materials: comfilcon A, senofilcon A, omafilcon B, fanfilcon A, balafilcon A, senofilcon C, and lehfilcon A. Lehfilcon A is a newly marketed silicon hydrogel contact lens with a surface modification of poly-(2-methacryloyloxyethyl phosphorylcholine) (PMPC). PMPC has previously been demonstrated to be an effective anti-biofouling treatment for numerous surfaces. We observed low S. marcescens adherence to lehfilcon A compared to other materials. We demonstrate the use of the fluorescent dye 5(6)-Carboxytetramethylrhodamine succinimidyl ester to covalently stain live cells prior to material adhesion studies.

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]

• 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]

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]

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]

Nosocomial and medical device-induced biofilm infections affect millions of lives and urgently require innovative preventive approaches. These pathologies have led to the development of numerous antimicrobial strategies, an emergent topic involving both natural and synthetic routes, among which some are currently under testing for clinical approval and use. Antimicrobial peptides (AMPs) are ideal candidates for this fight. Therefore, the strategies involving surface functionalization with AMPs to prevent bacterial attachment/biofilms formation have experienced a tremendous development over the last decade. In this review, we describe the different mechanisms of action by which AMPs prevent bacterial adhesion and/or biofilm formation to better address their potential as anti-infective agents. We additionally analyze AMP immobilization techniques on a variety of materials, with a focus on biomedical applications. Furthermore, we summarize the advances made to date regarding the immobilization strategies of AMPs on various surfaces and their ability to prevent the adhesion of various microorganisms. Progress toward the clinical approval of AMPs in antibiotherapy is also reviewed. [ABSTRACT FROM AUTHOR]

Zirconia is becoming reckoned as a promising solution for different applications, in particular those within the dental implant investigation field. It has been proved to successfully overcome important limitations of the commonly used titanium implants. The adhesion of microorganisms to the implants, in particular of bacteria, may govern the success or the failure of a dental implant, as the accumulation of bacteria on the peri-implant bone may rapidly evolve into periodontitis. However, bacterial adhesion on different zirconia architectures is still considerably unknown. Therefore, the adhesion of Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa to zirconia surfaces with different finishings was evaluated and compared to a titanium surface. The adhesion interaction between S. aureus and P. aeruginosa was also evaluated using a co-culture since these bacteria are infamous due to their common presence in chronic wound infections. Results showed that different bacterium species possess different properties which influence their propensity to adhere to different roughness levels and architectures. E. coli revealed a higher propensity to adhere to zirconia channelled surfaces (7.15 × 106 CFU/mL), whereas S. aureus and P. aeruginosa adhered more to the titanium control group (1.07 × 105 CFU/mL and 8.43 × 106 CFU/mL, respectively). Moreover, the co-culture denoted significant differences on the adhesion behaviour of bacteria. Despite not having shown an especially better behaviour regarding bacterial adhesion, zirconia surfaces with micro-channels are expected to improve the vascularization around the implants and ultimately enhance osseointegration, thus being a promising solution for dental implants. [Display omitted] • Zirconia is becoming reckoned as a promising solution for different applications. • The adhesion of E. coli, S. aureus and P. aeruginosa to zirconia surfaces with different finishings was evaluated. • E. coli revealed a higher propensity to adhere to zirconia channelled surfaces. • S. aureus and P. aeruginosa adhered more to the titanium control group. • Channelled zirconia surfaces are expected to improve the vascularization around the implants and enhance osseointegration. [ABSTRACT FROM AUTHOR]