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Henk J. Busscher - One of the best experts on this subject based on the ideXlab platform.
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interfacial re arrangement in initial Microbial Adhesion to surfaces
Current Opinion in Colloid and Interface Science, 2010Co-Authors: Henk J. Busscher, Willem Norde, Prashant K Sharma, Henny C Van Der MeiAbstract:Upon initial Microbial Adhesion to a surface, multiple events occur that include interfacial re-arrangements in the region between an adhering organism and a surface. Application of physico-chemical mechanisms to explain Microbial Adhesion to surfaces requires better knowledge of the interfacial re-arrangement occurring immediately after Adhesion than hitherto available.
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Microbial Adhesion to surface grafted polyacrylamide brushes after long term exposure to pbs and reconstituted freeze dried saliva
Journal of Biomedical Materials Research Part A, 2010Co-Authors: Irina Fundeanu, Henny C Van Der Mei, Arend J Schouten, Henk J. BusscherAbstract:Polyacrylamide (PAAm) brushes, covalently grafted from silicon wafer surfaces were examined for their ability to inhibit Microbial Adhesion after long-term exposure to PBS or reconstituted freeze-dried saliva for time intervals from 48 h up to 1 month at 37 � C. Microbial Adhesion after exposure was studied in a parallel plate flow chamber. Infrared spectra showed that PAAm brushes exhibit good chemical stability upon incubation in both PBS and reconstituted freeze-dried saliva up to 1 month. Reductions in Microbial Adhesion on PAAm brushes after exposure to PBS or reconstituted freeze- dried saliva varied from 63 to 93% depending on the Microbial strain considered, even after 1 month of exposure of the brushes to reconstituted freeze-dried saliva. V C 2010 Wiley
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polyacrylamide brush coatings preventing Microbial Adhesion to silicone rubber
Colloids and Surfaces B: Biointerfaces, 2008Co-Authors: Irina Fundeanu, Henny C Van Der Mei, Arend Jan Schouten, Henk J. BusscherAbstract:Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to Microbial Adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage Microbial Adhesion has thus far been impossible due to the hydrophobic character of its surface, surface deterioration upon treatment and instability of coatings under physiological conditions. Here we present a method to successfully grow polyacrylamide (PAAm) brushes from silicone rubber surfaces after removal of low molecular weight organic molecules (LMWOM), such as silane oligomers. PAAm brush coating did not cause any surface deterioration and discouraged Microbial Adhesion, even after 1-month exposure to physiological fluids. The method presented opens many new avenues for the use of silicone rubber as a biomaterial, without the risk of developing a biomaterial-centered infection.
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synthesis and characterization of surface grafted polyacrylamide brushes and their inhibition of Microbial Adhesion
Langmuir, 2007Co-Authors: Irina Cringusfundeanu, Henk J. Busscher, Henny C Van Der Mei, Jeroen Luijten, Arend Jan SchoutenAbstract:A method is presented to prevent Microbial Adhesion to solid surfaces exploiting the unique properties of polymer brushes. Polyacrylamide (PAAm) brushes were grown from silicon wafers by atom transfer radical polymerization (ATRP) using a three-step reaction procedure consisting of immobilization of a coupling agent γ-aminopropyltriethoxysilane, anchoring of an ATRP initiator 4-(chloromethyl)benzoyl chloride, and controlled radical polymerization of acrylamide. The surfaces were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ellipsometry, and contact-angle measurements. The calculated grafting density pointed to the presence of a dense and homogeneous polymer brush. Initial deposition rates, Adhesion after 4 h, and detachment of two bacterial strains (Staphylococcus aureus ATCC 12600 and Streptococcus salivarius GB 24/9) and one yeast strain (Candida albicans GB 1/2) to both PAAm-coated and untreated silicon surfaces were investigated in a parallel plate flow c...
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Microbial Adhesion in flow displacement systems
Clinical Microbiology Reviews, 2006Co-Authors: Henk J. Busscher, Henny C Van Der MeiAbstract:Flow displacement systems are superior to many other (static) systems for studying Microbial Adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications.
Willem Norde - One of the best experts on this subject based on the ideXlab platform.
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interfacial re arrangement in initial Microbial Adhesion to surfaces
Current Opinion in Colloid and Interface Science, 2010Co-Authors: Henk J. Busscher, Willem Norde, Prashant K Sharma, Henny C Van Der MeiAbstract:Upon initial Microbial Adhesion to a surface, multiple events occur that include interfacial re-arrangements in the region between an adhering organism and a surface. Application of physico-chemical mechanisms to explain Microbial Adhesion to surfaces requires better knowledge of the interfacial re-arrangement occurring immediately after Adhesion than hitherto available.
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surface tethered polymers to influence protein adsorption and Microbial Adhesion
ChemInform, 2007Co-Authors: Willem NordeAbstract:In various applications it is desired that biological cells or protein molecules are immobilized at surfaces. Examples are enzymes or cells in bioreactors and biosensors, immuno-proteins in solid-state diagnostics and proteinaceous farmacons in drug delivery systems. In order to retain biological activity, the structural integrity of the immobilized bio-compounds should be preserved. In other cases immobilization of cells and proteins should be avoided. Adsorption of proteins from biofluids is considered to be the first event in the biofouling process. Subsequently, bacterial and/or other biological cells (e.g., blood platelets, erythrocytes) deposit on the adsorbed protein layer and a biofilm is formed. This causes great problems in areas as diverse as biomedicine, food processing and the marine environment. A generic approach to influence the magnitude of the interaction between a particle (e.g., a cell or a globular protein molecule) and a sorbent material is to manipulate both the long- and short-range interaction forces by grafting soluble polymers or oligomers onto the sorbent surface. Application of oligomers of ethylene oxide (EO) prevents the particles from making intimate contact with the surface. Thus, adsorbed enzymes may retain their native structure and, hence, their enzymatic activity. Another interesting example is the steering effect of pre-adsorbed polymers of EO (PEO) on the orientation of subsequently depositing anisotropic particles. For instance, IgG molecules may be forced in the right orientation and conformation in the interstitial spaces between the PEO chains, therewith doubling the specific antigen binding capacity. By far the greatest part of recent research on modifying surfaces by grafting soluble polymers (usually PEO) aims at the prevention of protein adsorption and/or Adhesion of biological cells. Suppression of particle deposition depends primarily on two characteristics of the polymer layer: (a) the grafting density, and (b) the extension of the polymer layer into the solution. The efficacy of grafted PEO layers to reduce protein adsorption and Microbial Adhesion is illustrated for blood plasma proteins, saliva proteins and a number of bacterial and yeast cells.
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influence of shear on Microbial Adhesion to peo brushes and glass by convective diffusion and sedimentation in a parallel plate flow chamber
Colloids and Surfaces B: Biointerfaces, 2005Co-Authors: Astrid Roosjen, Willem Norde, Henk J. Busscher, Niels P BoksAbstract:Microbial Adhesion to surfaces often occurs despite high wall shear rates acting on the adhering microorganisms. In this paper, we compare the wall shear rates needed to prevent Microbial Adhesion to bare glass and poly(ethylene oxide) (PEO)-brush coated glass in a parallel plate flow chamber. Initial Microbial deposition rates were determined for different wall shear rates between 4 and 1600 s −1 on the top and bottom plates of the flow chamber. Deposition efficiencies αSL, based on the Smoluchowski–Levich approach, for Pseudomonas aeruginosa D1, Escherichia coli O2K2 and Candida tropicalis GB 9/9 decreased with increasing wall shear rates and were lower for PEO-brush coated glass than for bare glass. Characteristic shear rates preventing Adhesion to the bottom plate were around 10 and 1.0 s −1 for the bacteria on glass and the PEO-brush and 36 and 3.4 s −1 for the yeast strain on glass and the PEO-brush, respectively. This demonstrates that the adhesive forces between microorganisms and a PEO-brush are comparatively weak, although some strains may have the ability to adhere to a PEO-brush under low shear conditions. Microbial deposition efficiencies αSL were much larger, however, than unity for bottom plate deposition, but could be reduced to realistic values by averaging the deposition rates found for the top (negative contribution of sedimentation) and bottom (positive contribution of sedimentation) plates. © 2005 Elsevier B.V. All rights reserved.
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Microbial Adhesion to poly ethylene oxide brushes influence of polymer chain length and temperature
Langmuir, 2004Co-Authors: Astrid Roosjen, Henk J. Busscher, Willem NordeAbstract:Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated lengths in water of 2.8-, 7.5-, and 23.7-nm, respectively. Adhesion of two bacterial (Staphylococcus epidermidis and Pseudomonas aeruginosa) and two yeast (Candida albicans and Candida tropicalis) strains to these brushes was studied and compared to their Adhesion to bare glass. For the bacterium P. aeruginosa and the yeast C. tropicalis, Adhesion to the 2.8-nm brush was comparable to their Adhesion on bare glass, whereas Adhesion to the 7.5- and 23.7-nm brushes was greatly reduced. For S. epidermidis, Adhesion was only slightly higher to the 2.8-nm brush than that to the longer brushes. Adhesion of the yeast C. albicans to the PEO brushes was lower than that to glass, but no differences in Adhesion were found between the three brush lengths. After passage of an air bubble, nearly all microorganisms adhering to a brush were removed, irrespective of brush length, whereas retention of the adhering organisms on glass was much higher. No significant differences were found in Adhesion nor retention between experiments conducted at 20 and those conducted at 37 C.
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Microbial Adhesion to poly ethylene oxide brushes influence of polymer chain length and temperature
Langmuir, 2004Co-Authors: Astrid Roosjen, Henk J. Busscher, H.c. Van Der Mei, Willem NordeAbstract:Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated lengths in water of 2.8-, 7.5-, and 23.7-nm, respectively. Adhesion of two bacterial (Staphylococcus epidermidis and Pseudomonas aeruginosa) and two yeast (Candida albicans and Candida tropicalis) strains to these brushes was studied and compared to their Adhesion to bare glass. For the bacterium P. aeruginosa and the yeast C. tropicalis, Adhesion to the 2.8-nm brush was comparable to their Adhesion on bare glass, whereas Adhesion to the 7.5- and 23.7-nm brushes was greatly reduced. For S. epidermidis, Adhesion was only slightly higher to the 2.8-nm brush than that to the longer brushes. Adhesion of the yeast C. albicans to the PEO brushes was lower than that to glass, but no differences in Adhesion were found between the three brush lengths. After passage of an air bubble, nearly all microorganisms adhering to a brush were removed, irrespective of brush length, whereas retention of the adhering organisms on glass was much higher. No significant differences were found in Adhesion nor retention between experiments conducted at 20 and those conducted at 37 degrees C.
Henny C Van Der Mei - One of the best experts on this subject based on the ideXlab platform.
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interfacial re arrangement in initial Microbial Adhesion to surfaces
Current Opinion in Colloid and Interface Science, 2010Co-Authors: Henk J. Busscher, Willem Norde, Prashant K Sharma, Henny C Van Der MeiAbstract:Upon initial Microbial Adhesion to a surface, multiple events occur that include interfacial re-arrangements in the region between an adhering organism and a surface. Application of physico-chemical mechanisms to explain Microbial Adhesion to surfaces requires better knowledge of the interfacial re-arrangement occurring immediately after Adhesion than hitherto available.
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Microbial Adhesion to surface grafted polyacrylamide brushes after long term exposure to pbs and reconstituted freeze dried saliva
Journal of Biomedical Materials Research Part A, 2010Co-Authors: Irina Fundeanu, Henny C Van Der Mei, Arend J Schouten, Henk J. BusscherAbstract:Polyacrylamide (PAAm) brushes, covalently grafted from silicon wafer surfaces were examined for their ability to inhibit Microbial Adhesion after long-term exposure to PBS or reconstituted freeze-dried saliva for time intervals from 48 h up to 1 month at 37 � C. Microbial Adhesion after exposure was studied in a parallel plate flow chamber. Infrared spectra showed that PAAm brushes exhibit good chemical stability upon incubation in both PBS and reconstituted freeze-dried saliva up to 1 month. Reductions in Microbial Adhesion on PAAm brushes after exposure to PBS or reconstituted freeze- dried saliva varied from 63 to 93% depending on the Microbial strain considered, even after 1 month of exposure of the brushes to reconstituted freeze-dried saliva. V C 2010 Wiley
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polyacrylamide brush coatings preventing Microbial Adhesion to silicone rubber
Colloids and Surfaces B: Biointerfaces, 2008Co-Authors: Irina Fundeanu, Henny C Van Der Mei, Arend Jan Schouten, Henk J. BusscherAbstract:Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to Microbial Adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage Microbial Adhesion has thus far been impossible due to the hydrophobic character of its surface, surface deterioration upon treatment and instability of coatings under physiological conditions. Here we present a method to successfully grow polyacrylamide (PAAm) brushes from silicone rubber surfaces after removal of low molecular weight organic molecules (LMWOM), such as silane oligomers. PAAm brush coating did not cause any surface deterioration and discouraged Microbial Adhesion, even after 1-month exposure to physiological fluids. The method presented opens many new avenues for the use of silicone rubber as a biomaterial, without the risk of developing a biomaterial-centered infection.
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synthesis and characterization of surface grafted polyacrylamide brushes and their inhibition of Microbial Adhesion
Langmuir, 2007Co-Authors: Irina Cringusfundeanu, Henk J. Busscher, Henny C Van Der Mei, Jeroen Luijten, Arend Jan SchoutenAbstract:A method is presented to prevent Microbial Adhesion to solid surfaces exploiting the unique properties of polymer brushes. Polyacrylamide (PAAm) brushes were grown from silicon wafers by atom transfer radical polymerization (ATRP) using a three-step reaction procedure consisting of immobilization of a coupling agent γ-aminopropyltriethoxysilane, anchoring of an ATRP initiator 4-(chloromethyl)benzoyl chloride, and controlled radical polymerization of acrylamide. The surfaces were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ellipsometry, and contact-angle measurements. The calculated grafting density pointed to the presence of a dense and homogeneous polymer brush. Initial deposition rates, Adhesion after 4 h, and detachment of two bacterial strains (Staphylococcus aureus ATCC 12600 and Streptococcus salivarius GB 24/9) and one yeast strain (Candida albicans GB 1/2) to both PAAm-coated and untreated silicon surfaces were investigated in a parallel plate flow c...
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inhibition of Microbial Adhesion to silicone rubber treated with biosurfactant from streptococcus thermophilus a
Fems Immunology and Medical Microbiology, 2006Co-Authors: La Gia Rodrigues, Henny C Van Der Mei, Ibrahim M Banat, Josa Teixeira, R OliveiraAbstract:Microbial Adhesion of four bacterial and two yeast strains isolated from explanted voice prostheses to silicone rubber before and after conditioning with a biosurfactant obtained from the probiotic bacterium Streptococcus thermophilus A was investigated in a parallel plate flow chamber. The silicone rubber with and without an adsorbed biosurfactant layer was characterized using contact angle measurements. Water contact angles indicated that the silicone rubber surface with adsorbed biosurfactant was more hydrophilic (58 degrees) than bare silicone rubber (109 degrees). The results obtained showed that the biosurfactant was effective in decreasing the initial deposition rates, and the number of bacterial cells adhering after 4 h, for all microorganisms tested. A decrease in the initial deposition rate was observed for Rothia dentocariosa GBJ 52/2B and Staphylococcus aureus GB 2/1 from 1937 +/- 194 to 179 +/- 21 microorganisms cm(-2) s(-1) and from 1255 +/- 54 to 233 +/- 26 microorganisms cm(-2) s(-1), respectively, accounting for an 86% reduction of the initial deposition rate for both strains. The number of bacterial cells adhering to the silicone rubber with preadsorbed biosurfactant after 4 h was further reduced by 89% and 97% by the two strains, respectively. The two yeast strains tested showed less reduction in Adhesion after 4 h, to values between 67% and 70%. Such a pretreatment with surface-active compounds may constitute a promising strategy to reduce the Microbial colonization rate of silicone rubber voice prostheses.
H.c. Van Der Mei - One of the best experts on this subject based on the ideXlab platform.
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Microbial Adhesion to poly ethylene oxide brushes influence of polymer chain length and temperature
Langmuir, 2004Co-Authors: Astrid Roosjen, Henk J. Busscher, H.c. Van Der Mei, Willem NordeAbstract:Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated lengths in water of 2.8-, 7.5-, and 23.7-nm, respectively. Adhesion of two bacterial (Staphylococcus epidermidis and Pseudomonas aeruginosa) and two yeast (Candida albicans and Candida tropicalis) strains to these brushes was studied and compared to their Adhesion to bare glass. For the bacterium P. aeruginosa and the yeast C. tropicalis, Adhesion to the 2.8-nm brush was comparable to their Adhesion on bare glass, whereas Adhesion to the 7.5- and 23.7-nm brushes was greatly reduced. For S. epidermidis, Adhesion was only slightly higher to the 2.8-nm brush than that to the longer brushes. Adhesion of the yeast C. albicans to the PEO brushes was lower than that to glass, but no differences in Adhesion were found between the three brush lengths. After passage of an air bubble, nearly all microorganisms adhering to a brush were removed, irrespective of brush length, whereas retention of the adhering organisms on glass was much higher. No significant differences were found in Adhesion nor retention between experiments conducted at 20 and those conducted at 37 degrees C.
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comparison of velocity profiles for different flow chamber designs used in studies of Microbial Adhesion to surfaces
Applied and Environmental Microbiology, 2003Co-Authors: Dewi P Bakker, Henk J. Busscher, A Van Der Plaats, Gijsbertus Jacob Verkerke, H.c. Van Der MeiAbstract:Flow chambers are commonly used to study Microbial Adhesion to surfaces under environmentally relevant hydrodynamic conditions. The parallel plate flow chamber (PPFC) is the most common design, and mass transport occurs through slow convective diffusion. In this study, we analyzed four different PPFCs to determine whether the expected hydrodynamic conditions, which control both mass transport and detachment forces, are actually achieved. Furthermore, the different PPFCs were critically evaluated based on the size of the area where the velocity profile was established and constant with a range of flow rates, indicating that valid observations could be made. Velocity profiles in the different chambers were calculated by using a numerical simulation model based on the finite element method and were found to coincide with the profiles measured by particle image velocimetry. Environmentally relevant shear rates between 0 and 10,000 s 1 could be measured over a sizeable proportion of the substratum surface for only two of the four PPFCs. Two models appeared to be flawed in the design of their inlets and outlets and allowed development of a stable velocity profile only for shear rates up to 0.5 and 500 s 1 . For these PPFCs the inlet and outlet were curved, and the modeled shear rates deviated from the calculated shear rates by up to 75%. We concluded that PPFCs used for studies of Microbial Adhesion to surfaces should be designed so that their inlets and outlets are in line with the flow channel. Alternatively, the channel length should be increased to allow a greater length for the establishment of the desired hydrodynamic conditions.
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in vitro and in vivo Microbial Adhesion and growth on argon plasma treated silicone rubber voice prostheses
Journal of Materials Science: Materials in Medicine, 1998Co-Authors: Emmanuel Paul Jos Marie Everaert, Henk J. Busscher, H.c. Van Der Mei, B Van De Beltgritter, G J Verkerke, F Dijk, Hans F Mahieu, A ReitsmaAbstract:Patients who undergo a total laryngectomy usually receive a silicone rubber voice prosthesis for voice rehabilitation. Unfortunately, biofilm formation on the esophageal side of voice prostheses limits their lifetime to 3–4 mon on average. The effects of repeated argon plasma treatment of medical grade, hydrophobic silicone rubber on in vitro Adhesion and growth of bacteria and yeasts isolated from voice prostheses, as well as in vivo biofilm formation are presented here. In vitro experiments demonstrated that initial Microbial Adhesion over a 4 h time span to plasma-treated, hydrophilized, silicone rubber was generally less than on original, hydrophobic silicone rubber, both in the absence and presence of a salivary conditioning film on the biomaterial. Growth studies over a time period of 14 d at 37°C in a modified Robbins device, showed that fewer Candida cells adhered on plasma-treated, hydrophilized silicone rubber as compared to on original, hydrophobic silicone rubber. For the in vivo evaluation of biofilm formation on plasma-treated silicone rubber voice prostheses, seven laryngectomized patients received a partly hydrophilized “Groningen Button” voice prosthesis for a planned evaluation period of 4 wk. After removal of the voice prostheses, the border between the hydrophilized and the original, hydrophobic side of the prostheses was clearly visible. However, biofilm formation was, unexpectedly, less on the original, hydrophobic sides, although the Microbial compositions of the biofilms on both sides were not significantly different. Summarizing, this study demonstrates that in vitro Microbial Adhesion and growth on silicone rubber can be reduced by plasma treatment, but in vivo biofilm formation on silicone rubber voice prostheses is oppositely enhanced by hydrophilizing the silicone rubber surface. Nevertheless, from the results of this study the important conclusion can be drawn that in vivo biofilm formation on voice prostheses is controlled by the hydrophobicity of the biomaterials surface used. © 1998 Chapman & Hall
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physico chemical interactions in initial Microbial Adhesion and relevance for biofilm formation
Advances in Dental Research, 1997Co-Authors: H J Busscher, H.c. Van Der MeiAbstract:This paper summarizes initial Microbial Adhesion events in dental plaque formation, including the physico-chemistry of the interaction between micro-organisms and solid substrata, detachment phenomena under the fluctuating shear of the oral cavity, co-Adhesion between pairs of Microbial strains, and biosurfactant release. A hypothesis is forwarded on how these initial events might influence the final Microbial composition and structure of the plaque, although it is simultaneously emphasized that the necessary techniques for verification of the hypothesis have only recently become available, and supporting evidence is still to be collected.
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initial Microbial Adhesion is a determinant for the strength of biofilm Adhesion
Fems Microbiology Letters, 1995Co-Authors: Henk J. Busscher, R R M Bos, H.c. Van Der MeiAbstract:This paper presents a hypothesis on the importance of initial Microbial Adhesion in the overall process of biofilm formation. The hypothesis is based on the realization that dynamic shear conditions exist in many environments, such as in the oral cavity, or on rocks and ship hulls. Recognizing that an entire biofilm is detached during high shear once the bond between the initially adhering organisms and a surface (often constituted through a so-called ‘conditioning film’) is broken, it becomes clear that research should focus on detachment rather than Adhesion. Experiments were done in a parallel plate flow chamber in which attempts were made to detach adhering oral streptococci from glass by applying a high shear caused by the passage of a bubble, giving an air-liquid interface. Detachment of streptococci from bare glass and from an initially adhering actinomycete strain appeared not to occur. However, substantial detachment of adhering streptococci occurred when Adhesion was mediated through a salivary conditioning film, presumably because of cohesive failure in the conditioning film.
Astrid Roosjen - One of the best experts on this subject based on the ideXlab platform.
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influence of shear on Microbial Adhesion to peo brushes and glass by convective diffusion and sedimentation in a parallel plate flow chamber
Colloids and Surfaces B: Biointerfaces, 2005Co-Authors: Astrid Roosjen, Willem Norde, Henk J. Busscher, Niels P BoksAbstract:Microbial Adhesion to surfaces often occurs despite high wall shear rates acting on the adhering microorganisms. In this paper, we compare the wall shear rates needed to prevent Microbial Adhesion to bare glass and poly(ethylene oxide) (PEO)-brush coated glass in a parallel plate flow chamber. Initial Microbial deposition rates were determined for different wall shear rates between 4 and 1600 s −1 on the top and bottom plates of the flow chamber. Deposition efficiencies αSL, based on the Smoluchowski–Levich approach, for Pseudomonas aeruginosa D1, Escherichia coli O2K2 and Candida tropicalis GB 9/9 decreased with increasing wall shear rates and were lower for PEO-brush coated glass than for bare glass. Characteristic shear rates preventing Adhesion to the bottom plate were around 10 and 1.0 s −1 for the bacteria on glass and the PEO-brush and 36 and 3.4 s −1 for the yeast strain on glass and the PEO-brush, respectively. This demonstrates that the adhesive forces between microorganisms and a PEO-brush are comparatively weak, although some strains may have the ability to adhere to a PEO-brush under low shear conditions. Microbial deposition efficiencies αSL were much larger, however, than unity for bottom plate deposition, but could be reduced to realistic values by averaging the deposition rates found for the top (negative contribution of sedimentation) and bottom (positive contribution of sedimentation) plates. © 2005 Elsevier B.V. All rights reserved.
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Microbial Adhesion to poly ethylene oxide brushes influence of polymer chain length and temperature
Langmuir, 2004Co-Authors: Astrid Roosjen, Henk J. Busscher, Willem NordeAbstract:Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated lengths in water of 2.8-, 7.5-, and 23.7-nm, respectively. Adhesion of two bacterial (Staphylococcus epidermidis and Pseudomonas aeruginosa) and two yeast (Candida albicans and Candida tropicalis) strains to these brushes was studied and compared to their Adhesion to bare glass. For the bacterium P. aeruginosa and the yeast C. tropicalis, Adhesion to the 2.8-nm brush was comparable to their Adhesion on bare glass, whereas Adhesion to the 7.5- and 23.7-nm brushes was greatly reduced. For S. epidermidis, Adhesion was only slightly higher to the 2.8-nm brush than that to the longer brushes. Adhesion of the yeast C. albicans to the PEO brushes was lower than that to glass, but no differences in Adhesion were found between the three brush lengths. After passage of an air bubble, nearly all microorganisms adhering to a brush were removed, irrespective of brush length, whereas retention of the adhering organisms on glass was much higher. No significant differences were found in Adhesion nor retention between experiments conducted at 20 and those conducted at 37 C.
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Microbial Adhesion to poly ethylene oxide brushes influence of polymer chain length and temperature
Langmuir, 2004Co-Authors: Astrid Roosjen, Henk J. Busscher, H.c. Van Der Mei, Willem NordeAbstract:Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated lengths in water of 2.8-, 7.5-, and 23.7-nm, respectively. Adhesion of two bacterial (Staphylococcus epidermidis and Pseudomonas aeruginosa) and two yeast (Candida albicans and Candida tropicalis) strains to these brushes was studied and compared to their Adhesion to bare glass. For the bacterium P. aeruginosa and the yeast C. tropicalis, Adhesion to the 2.8-nm brush was comparable to their Adhesion on bare glass, whereas Adhesion to the 7.5- and 23.7-nm brushes was greatly reduced. For S. epidermidis, Adhesion was only slightly higher to the 2.8-nm brush than that to the longer brushes. Adhesion of the yeast C. albicans to the PEO brushes was lower than that to glass, but no differences in Adhesion were found between the three brush lengths. After passage of an air bubble, nearly all microorganisms adhering to a brush were removed, irrespective of brush length, whereas retention of the adhering organisms on glass was much higher. No significant differences were found in Adhesion nor retention between experiments conducted at 20 and those conducted at 37 degrees C.