Biofouling最新文献

This study examined the corrosion inhibition mechanisms of extracellular polymeric substances (EPS) from Lactobacillus reuteri, Pseudomonas fluorescens, and Escherichia coli on carbon steel. Using UV spectrophotometry, LC-MS, infrared spectroscopy, and atomic force microscopy (AFM), it was apparent that all three EPS effectively inhibited corrosion, with optimal concentrations of 300 mg/L for Lactobacillus reuteri and 400 mg/L for the other species, yielding inhibition efficiencies of 28.25%, 23.87%, and 21.72%, respectively. The carboxyl group content was critical, with Lactobacillus reuteri EPS having the highest proportion. Functional group analysis showed it contained 12.39% and 12.93% more carboxyl groups than those from Pseudomonas fluorescens and Escherichia coli. Iron ion adsorption was primarily physical and occurred in a monolayer, with a greater capacity for Fe³⁺ than Fe²⁺, peaking at 600 mg/L.

Urinary infections caused by Staphylococcus aureus are commonly associated with urinary catheterization and often result in severe complications. Given this problem, the objective of the study was to investigate the preventive action of promethazine (PMT) against the formation of methicillin-resistant Staphylococcus aureus (MRSA) biofilms when impregnated in urinary catheters. For this purpose, techniques such as broth microdilution, checkerboard, impregnation on urinary catheter fragments, flow cytometry assays and scanning electron microscopy were employed. PMT exhibited antimicrobial activity with Minimum Inhibitory Concentration (MIC) values ranging from 171 to 256 µg/mL, predominantly additive interaction in combination with oxacillin (OXA) and vancomycin (VAN), and a reduction in cell viability of biofilms formed and forming by methicillin-sensitive and -resistant S. aureus. Morphological alterations, damage to the membrane, and genetic material of cells treated with promethazine were also observed. The results demonstrated that PMT can be classified as a promising antimicrobial agent for use in the antibacterial coating of long-term urinary devices.

The efficacy of carbon dioxide (CO₂) to reduce biofouling by quagga mussels (Dreissena rostriformis bugensis) in raw water systems was investigated. Experiments were conducted in a mobile laboratory located at Bureau of Reclamation Davis Dam Hydropower Facility and supplied with raw water from Lake Mohave, a reservoir of the Colorado River, USA. Incoming water was split between five chambers, each infused with CO₂ at a different rate. Raw reservoir water containing quagga larvae (veligers) was mixed with CO₂ chamber outflows and delivered to tanks containing settlement plates. Two experiments were conducted. Experiment 1 tested continuous infusion at target concentrations of 30, 45, 60, 75, and 100 mg L^-1 dCO₂ (dissolved CO₂). Experiment 2 evaluated intermittent infusion schedules: 24 h on/off with 50, 75, and 100 mg L^-1 dCO₂ and 24 h once/week with 100 mg L^-1 dCO₂. In Experiment 1, the percent settlement decreased with mean CO₂ concentration, ranging from 5.0% to < 0.1% in 28.7 and 92.2 mg L^-1 dCO₂, respectively. In Experiment 2, the efficacy of 24 h on/off at dCO₂ > 72.2 mg L^-1 was similar to continuous treatment. The least effective treatment was 24 h once weekly at 95 mg L^-1 dCO₂. These results demonstrate that CO₂ treatment may reduce mussel biofouling in raw water systems.

Zoono GermFree24 is a quaternary ammonium compound-based hand sanitiser. Its efficacy against planktonic bacteria is well established, but efficacy against biofilms has not been tested. We investigated the antibiofilm efficacy of Zoono GermFree24 hand sanitiser and a modified formulation against biofilms of Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 27853 grown in vitro using the Centers for Disease Control (CDC) biofilm reactor and 96-pin lids. Biofilms were immersed in Zoono GermFree24 or Zoono B22-1402A (modified formulation) for 5 min, 1 h, 6 h or overnight (22 ± 2 h). The antiseptic was neutralised and the bacteria remaining after treatment were cultured and quantified. Zoono GermFree24 and Zoono B22-1402A caused time-dependent reductions in viable biofilms of both species with both methods of culture and testing, with more rapid biofilm eradication observed for Zoono B22-1402A. Biofilms grown on 96-pin lids were more quickly eradicated than those grown in the CDC biofilm reactor.

The ability of different microbes to form biofilms on materials found in aviation fuel systems was assessed using both individual isolates and complex microbial communities. Biofilm formation by the Gram-negative bacterium, Pseudomonas putida, the fungus Amorphotheca resinae and the yeast, Candida tropicalis, was influenced by material surface properties although this differed between isolates. Biofilm formation was greatest at the fuel-water interface. The Gram-positive bacterium Rhodococcus erythropolis, in contrast, was able to grow on most surfaces. When a subset of materials was exposed to complex microbial communities, the attached microbial community structure was influenced by surface properties and selected for different genera best able to form biofilms on a specific surface. Distinct sub-populations of Pseudomonads were identified, which favoured growth on aluminium or painted surfaces, with a different subpopulation favouring growth on nitrile.

Surface biofouling reduces the efficiency and lifespan of equipment across many industries. The development of high-performance antifouling surfaces, such as foul release coatings, benefits from test methods that can quickly identify superior antifouling surfaces in the laboratory during material development. Existing test methods poorly discriminate between different foul release coatings. Here is presented a method to assess the ability of surfaces to resist mussel adhesion using a quantitative, controlled single thread adhesion test (STAT) method, allowing for meaningful comparisons between low adhesion foul release surfaces. This method provides greater accuracy and finer resolution than push-based mussel shear adhesion methods without the difficulties associated with mussel size, thread attachment angle, or harming the mussels. The single thread tensile method is demonstrated on a variety of standard and high-performance coatings, and it is shown that the method detects differentiation between commercial foul release coatings that could not be resolved using other methods.

This study aimed to develop and characterize sodium alginate (SA)/chitosan (CS) based nanoparticles (NPs), with or without morin or carvacrol, and to evaluate the antimicrobial and antibiofilm activity against polymicrobial oral biofilms. Three different NPs (0.15:1; 0.3:1; 0.5:1 CS:SA) whether or not containing morin or carvacrol were developed and characterized by particle size, zeta potential, scanning electron microscope (SEM), encapsulation efficiency, and in vitro drug release. NPs antibiofilm and antimicrobial activity were evaluated using polymicrobial oral biofilms by means of quantifying the biomass, assessment of viable microorganisms (CFU/mL), and acidogenicity of the biofilm by pH readings. The NPs presented nanometric size (<500 nm), with spherical shape and smooth surface. Encapsulation efficiency of the samples containing morin ranged from 46.17 to 55.15% and for carvacrol from 55.30 to 90.15%. Total release of carvacrol and morin occurred within 15 min. The NPs significantly reduced biofilm biomass and microbial viability compared to the control. However, did not significantly increase the biofilm pH. The NPs were effectively synthesized and showed antimicrobial and antibiofilm effect against oral biofilm and the addition of natural substances morin or carvacrol increased this effect. Combination of chitosan and sodium alginate and addition of morin or carvacrol in NPs can be a promising strategy for oral use, fighting biofilm and consequently biofilm dependent diseases.

Biofilms are common in water systems and can lead to mechanical failure or illness of water system users. Methods for evaluating anti-fouling coatings have largely been informed by the medical industry and have not been tailored to industrial or spacecraft water systems. The goal of the paper is to help guide researchers in designing experiments to evaluate coatings that accurately represent the system under investigation. This review identified eight experimental design considerations when evaluating coatings in water systems: biofilm reactor operation, microorganism selection, reinoculation, coating surface area, liquid medium, experiment duration, coating performance evaluation, and the use of microgravity. The impact of each decision made within each of these considerations is presented. Further, the methods featured in eight studies investigating coatings for Earth-based or spacecraft water systems are discussed. This review serves to guide researchers toward improved experimental design to enable successful technology transfer from the lab bench to Earth and beyond.

Oil booms are used in the containment of oil leaking from ships moored in harbors around the world. However, marine biofouling quickly accumulates on these materials. The application of coatings offers a potential solution by preventing the growth of these organisms, but issues with adhesion of coatings to the oil boom materials remain a large barrier to success. This work is focused on testing the adhesion of marine coatings systems to oil boom fabrics after use of surface treatments or adhesion promoters. Surface analysis of fabrics showed a large variation in surface energy, contributing to the adhesion of coatings to these substrates. A laboratory water-jet adhesion-screening test identified several combinations of surface treatments and adhesion promoters that improved adhesion of coatings to various oil boom substrates. Large-scale field-testing of these candidates displayed improved cleanability, which translated into an increase in service life for coated oil boom fabrics.

In this study, we evaluated the impact of Epigalocatechin-3-gallate (EGCG) on S. mutans biofilm development for 24 and 46 h using high-resolution confocal laser scanning microscopy. EGCG treatment led to the formation of interspaced exopolysaccharide (EPS)-microcolony complexes unevenly distributed on the surface of hydroxyapatite disc, forming a thinner and less complex biofilm structure with significantly reduced biomass, matrix volume, and thickness compared to the NaCl treated group (negative control). At 46 h, the biofilm of the EGCG-treatment group failed to form the bacterial-EPS superstructures which is characteristic of the biofilm in the negative control group. EGCG treatment seems to significantly delay biofilm development, with the 46 h biofilm in the EGCG treatment group resembling the negative control group at 24 h. EGCG topical treatments impaired S. mutans biofilm initial growth and maturation, suggesting its potential to be used as a preventive agent against dental caries.