Studies Regarding the Formation and Temporal Dynamics of Bacterial Biofilms on the Hydrophile Surface of Glass in Static and Dynamic Conditions (original) (raw)
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Differences in colonisation of five marine bacteria on two types of glass surfaces
Biofouling, 2009
The retention patterns of five taxonomically different marine bacteria after attachment on two types of glass surfaces, as-received and chemically etched, have been investigated. Contact angle measurements, atomic force microscopy (AFM), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray fluorescence spectroscopy (XRF) and X-ray photoelectron spectrometry (XPS) were employed to investigate the impact of nanometer scale surface roughness on bacterial attachment. Chemical modification of glass surfaces resulted in a *1 nm decrease in the average surface roughness (R a ) and the root-mean-squared roughness (R q ) and in a *8 nm decrease in the surface height and the peak-to-peak (R max ) and the 10-point average roughness (R z ). The study revealed amplified bacterial attachment on the chemically etched, nano-smoother glass surfaces. This was a consistent response, notwithstanding the taxonomic affiliation of the selected bacteria. Enhanced bacterial attachment was accompanied by elevated levels of secreted extracellular polymeric substances (EPS). An expected correlation between cell surface wettability and the density of the bacterial attachment on both types of glass surfaces was also reported, while no correlation could be established between cell surface charge and the bacterial retention pattern.
PLOS ONE
Adherence of the microorganism to submerged solid surfaces leads to biofilm formation. Biofilm formation modifies the surfaces in favor of bacteria facilitating the survival of the bacteria under different stressed conditions. On the other hand, the formation of biofilm has a direct adverse economic impact in various industries and more importantly in medical practices. This adherence is the reason for the failure of many indwelling medical devices. Surface biofilm adhesion is the key to biofilm growth and stability. Hence this adhesion needs to be substantially lowered to inhibit biofilm stability. Both chemical and physical properties of the surface influence biofilm formation and modulating these properties can control this formation. In this study, we have investigated the effect of Hydrofluoric acid (HF), at a specific concentration as an etchant, on the surface morphology of substrates and the growth of biofilms of Pseudomonas aeruginosa. and Staphylococcus aureus. We find that the bacterial counts on the etched surfaces undergo a periodic increase and decrease. This, on one hand, shows the close correlation between the biofilm growth and the particular roughness scale, and on the other hand, explains the existing contradictory results regarding the effects of etching on substrate roughness and biofilm growth. We propose a simple model of a sequence of hole formation, hole expansion and etching away of the hole walls to form a new, comparatively smooth surface, coupled with the preferential accumulation of bacteria at the hole edges, to explain these periodicities.
Development and Analysis of Anaerobic Biofilms Onto Hydrophobic and Hydrophilic Surfaces
Environmental Technology, 2004
Fluorescent in situ hybridization (FISH) with domain and group specific probes that target intracellular 16S rRNA were used to investigate microbial composition of anaerobic biofilms developed on polypropylene (hydrophobic) and glass (hydrophilic) surfaces fitted inside a Modified Robbins Device (MRD). Crushed anaerobic granular sludge was used as inoculum for biofilm development in the MRD. The inoculum and biofilms formed showed nearly the same microbial composition, both were dominated by hydrogenotrophic methanogenic Archaea related to the Methanobacteriaceae as detected by the specific probe (MB1174). This group accounted for 44 to 90% of the DAPI-stained cells. Cells which hybridized to the Bacteria specific probe (EUB338) accounted for 3-18% of the DAPI-stained cells. After the first day of the biofilm formation experiment, a larger number of cells, 4.6 x 10 4 cells mm -2 , could be seen colonizing the polypropylene coupon compared to the glass, 8.2 x 10 3 cells mm -2 . However, after 9 days these numbers were very similar, i.e. 6.3 x 10 5 cells mm -2 and 7.2 x 10 5 cells mm -2 , for the glass and polypropylene coupons, respectively. Our data suggest that the hydrophobicity of the support material did not influence the initial development and the microbial composition of anaerobic biofilms developed in the MRD.
Bacterial Biofilm in Seawater: Cell Surface Properties of Early-attached Marine Bacteria
Biofouling, 2003
The development of antifouling strategies in seawater requires knowledge of the physico-chemical properties of the cell surfaces of early adherent bacteria. The hydrophilic, electrostatic and the Lewis acid-base cell surface properties of eleven marine bacteria were characterized. Although these bacteria adhered to a hydrophilic support immersed for 3 and 6 h, they presented various physico-chemical properties. Eleven strains possessed a hydrophilic surface and five a hydrophobic surface. Although the majority of the bacteria presented an electron-donating character, some could not generate Lewis acid-base interactions with the support. On the other hand, all strains possessed an isoelectric point ranging from 2.2 to 3.4 and were negatively charged at the pH of seawater. Hydrophilicity was a preponderant property among these bacteria, but other properties should not be ignored. The development of new antifouling paints must take account all the possible interaction levels used by the bacteria to adhere to an immersed surface.
BIOFILM Formation: A Comprehensive Review
International Journal of Pharma Research and Health Sciences, 2015
The phenomenon of bacterial adhesion is an important phenomenon for those working within the pharmaceutical and healthcare sectors to consider. This is because many processes are centered on the removal of bacteria. The adhesion of bacteria to surfaces relates to such factors as surface charge, surface energy, and the characteristics of polymers on bacteria (leading to the formation of biofilms). The way in which bacterial cells adhere to surfaces, or within communities, is of great importance to pharmaceutical microbiologists. When describing bacterial adhesion one is simply describing one or more stages of biofilm development, neglecting the fact that the population may not reach maturity. This article provides an overview of bacterial adhesion and its chemistry.
Transactions of the ASAE, 2002
A tool for the rapid analysis of biofilms, using epifluorescence microscopy and image analysis was developed. The tool allows the evaluation of overall biofilm coverage and biofilm patch morphology. It will provide a quantitative method for identifying relationships between biofilms and their substrates and for identifying the morphology of patches of damaged bacteria. The coverage percentage allows evaluation of the growth of biofilms and will allow the evaluation of the effectiveness of sanitizers and mechanical cleaning methods in removing biofilms from food processing surfaces. The patch morphology is useful for investigating the relationships between surface morphology and biofilm growth and for determining the surface morphology, biofilm shape, and sanitizer effectiveness. The software was tested and validated using biofilms of E. coli K12 on glass, polished 316 stainless steel, and brushed 316 stainless steel. The biofilms were stained with both propidium iodide and SYTO-16. After performing digital image analysis of both overall coverage and biofilm patch morphometrics, it was found that the percentages of living or total biofilm were independent of the substrate material. However, the absolute area of individual biofilm patches varied depending on the substrate material. These areas also showed changes over time. The circularity of the biofilm patches was investigated. At the end of the studies, the shape of most of the biofilm patches in this group was nearly circular.
Adhesion of Pseudomonas fluorescens biofilms to glass, stainless steel and cellulose
Biotechnology Letters, 2016
Objectives: The adhesion of colloidal probes of stainless steel, glass and cellulose to Pseudomonas fluorescens biofilms was examined using atomic force microscopy (AFM) to allow comparisons between surfaces to which biofilms might adhere. Results: Biofilm was grown on a stainless steel substrate and covered most of the surface after 96 h. AFM approach and retraction curves were obtained when the biofilm was immersed in a tryptone/soy medium. On approach, all the colloidal probes experienced a long non-contact phase more than 100 nm in length, possibly due to the steric repulsion by extracellular polymers from the biofilm and hydrophobic effects. Retraction data showed that the adhesion varied from position to position on the biofilm. The mean value of adhesion of glass to the biofilm (48 ± 7 nN) was the greatest, followed by stainless steel (30 ± 7 nN) and cellulose (7.8 ± 0.4 nN). Conclusion: The method allows understanding of adhesion between the three materials and biofilm, and ...
In situ analysis of biofilms on historic window glass using confocal laser scanning microscopy
Journal of Cultural Heritage, 2001
Microbial colonization of the surface of historic glass panels and the subsequent biodeteroration of glass are well documented phenomena. Yet little is known about the composition of this microflora that has to be adapted to low nutrient conditions and a dry environment. The microbial community growing on glass window panels from four different locations and ages ranging from 30 to 600 years was analyzed in situ using confocal laser scanning microscopy with nucleic acid stains and fluorescently labeled rRNA-targeted oligonucleotide probes for the domains Bacteria and Eucarya. A typical biofilm of the studied glasses displayed a total thickness of approximately 10-60 µm. Microbial colonization of the glass surface was heterogeneous at 0.8-7% areal coverage. The dominant microbial group belonged to the filamentous fungi. A different attached microflora was found only on one glass surface. This sample was sparsely colonized with areal coverage of 0.8% and a thickness of 10-20 µm; the biofilm consisted of single bacterial cells and microcolonies. Chemical composition and durability of the glass samples and availability of an additional organic layer were important factors influencing the extent of microbial growth. Information about the thickness and microbial composition of biofilms offer an essential background to optimize cleaning procedures or conservation strategies for stained glass windows.