References of "Van de Weerdt, Cécile"
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See detailPrevention of bacterial biofilms onto stainless steel substrates by immobilization of antimicrobial and anti-biofilm biomolecules
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Faure, Emilie ULg et al

Conference (2011)

Stainless steel is widely used in the daily life in building and food industries as well as in the medical field. However, at long term, bacteria succeed in adhering, proliferating and forming a resistant ... [more ▼]

Stainless steel is widely used in the daily life in building and food industries as well as in the medical field. However, at long term, bacteria succeed in adhering, proliferating and forming a resistant biofilm on stainless steel. Therefore, surface modification is needed providing metal surface with antibacterial, anti-adhesion and easy cleaning properties. Several biomolecules (antimicrobial peptides, antiadhesion biomolecules and anti-biofilm enzymes) were immobilized on stainless steel thanks to different immobilization techniques. In a first approach, cationic peptides have been embedded in a LBL architecture comprising anti-adhesion biomolecules. In a second approach, small inorganic-binding peptides isolated by phage display technology and recognizing specifically the steel surface were used as linker for antimicrobial peptide immobilization. Finally, antibacterial peptides were covalently grafted onto an organic-polymeric interlayer deposited by plasma. Resulting antibacterial, antiadhesion and anti-biofilm properties were characterized and the advantages of each immobilization technique were documented. The biocidal effect of these surfaces was demonstrated against Gram+/- bacteria. Coated stainless steel surfaces led to 95% reduction of S. epidermidis adhesion vs bare substrate. By combining both antibacterial and anti-adhesion biomolecules, we produced stainless steel surfaces with better cleanability. A biofilm-releasing glycoside hydrolase was also immobilized on the surface and showed to confer anti-biofilm properties to stainless steel. Moreover, we provide valuable insight about the resistance of the coating to close to real life cleaning conditions. [less ▲]

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See detailBiomimetic coatings with robust antibacterial properties
Jérôme, Christine ULg; Cécius, Michaël; Faure, Emilie ULg et al

Conference (2010, July 01)

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See detailSingle molecule interactions of bio-adhesive-inspired polymers with inorganic and organic surfaces
Willet, Nicolas ULg; Giamblanco, Nicoletta ULg; Faure, Emilie ULg et al

Conference (2010, July)

Numerous living creatures have developed adhesion strategies to stick to inorganic or organic surfaces in wet environments. A classic example of permanent bioadhesion is exemplified by mussels, which ... [more ▼]

Numerous living creatures have developed adhesion strategies to stick to inorganic or organic surfaces in wet environments. A classic example of permanent bioadhesion is exemplified by mussels, which secrete adhesive proteins containing a high concentration of 3,4-dihydroxyphenylalanine (DOPA) 1, 2. The catechol species of DOPA are thought to be responsible for the strong adhesion to inorganic surfaces, whereas the oxidized o-quinone species trigger the cross-linking of the glue, ensuring cohesion. The unoxidized form of DOPA is known to adhere to a large variety of inorganic surfaces, although the adhesion mechanism is not yet fully understood.3, 4 A clear understanding is however essential for the design of synthetic adhesive polymers required in many surface science applications. Here we investigate at the single-molecule level the interaction forces between AFM tips coated with bio-inspired polymers and a variety of inorganic and organic surfaces. We prepared polymers bearing several amounts of DOPA units and covalently attached them to AFM tips following our previously published strategy.5, 6 They were homo-or co-polymers and were cross-linked or not. These original bio-inspired tips were used to perform single-molecule force spectroscopy on a range of model, as well as industrial such as stainless and galvanized steel, substrates. The specific interaction forces measured in water were compared with the ones exerted by the same polymers without DOPA. It was found that, depending on the nature of the substrate, the presence of DOPA strongly, or only slightly, increases the interaction forces with the surface. We also investigated the influence of the oxidation state of the catechol species on the intensity of the interaction forces. Again, this influence is strongly related to the nature of the substrate. Finally, we studied the effect of polymer cross-linking on the adhesive interactions. 1. Waite, J. H.; Tanzer, M. L. Science 1981, 212, 1038. 2. Waite, J. H.; Housley, T. J.; Tanzer, M. L. Biochemistry 1985, 24, 5010. 3. Lee, H.; Scherer, N. F.; Messersmith, P. B. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 12999. 4. Wang, J.; Nawaz Tahir, M.; Kappl, M.; Tremel, W.; Metz, N.; Barz, M.; Theato, P.; Butt, H.-J. Adv. Mater. 2008, 20, 3872. 5. Gabriel, S.; Jérôme, C; Jérôme, R.; Fustin, C.-A.; Pallandre, A.; Plain, J.; Jonas, A. M.; Duwez, A.-S. J. Am. Chem. Soc. 2007, 129, 8410. 6. Cecchet, F.; Lussis, P.; Jérôme, C.; Gabriel, S.; Silva-Goncalves, E.; Jérôme, R.; Duwez, A.-S. Small 2008, 4, 1101. [less ▲]

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See detailNanocoatings of inorganic surfaces by molecular biomimetic
Vreuls, Christelle ULg; Genin, Alexis ULg; Zocchi, Germaine ULg et al

Poster (2010, June 30)

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See detailA green and refillable antibacterial coating for stainless steel
Faure, Emilie ULg; Charlot, Aurélia; Sciannaméa, Valérie et al

Poster (2010, June 29)

Because of its resistance to corrosion and chemicals, relevant mechanical and esthetical properties, stainless steel (SS) is widely used in the daily life (food industry, household appliances, surgery … ... [more ▼]

Because of its resistance to corrosion and chemicals, relevant mechanical and esthetical properties, stainless steel (SS) is widely used in the daily life (food industry, household appliances, surgery …). However, SS is unable to prevent bacteria from adhering, proliferating and forming a resistant biofilm when ageing. Therefore, surface modification is needed for providing durable antibacterial properties. We report here on an all-in-one approach to prepare refillable antimicrobial films using the layer-by-layer deposition of polyelectrolytes. Specifically designed biocidal multilayered polyelectrolyte films that bear 3,4-dihydroxyphenylalanine (DOPA), known as a promoter of adhesion to inorganic surfaces, were deposited onto SS. DOPA was incorporated in the polycationic chains by radical copolymerisation of N-methacrylated DOPA with the quaternary ammonium salt of 2-(dimethylamino)ethyl methacrylate (DMAEMA+). In order to boost the antibacterial activity of the polycationic layer, AgNO3 was added to the aqueous solution of P(DOPA)-co-P(DMAEMA+), which resulted in the in-situ formation of silver based nanoparticles, sources of biocial Ag+. The layer-by-layer deposition of aqueous P(DOPA)-co-P(DMAEMA+)/AgCl/Ag0 suspension and aqueous solution of poly(styrene sulfonate) provides high antibacterial activity against Gram-negative E. Coli bacteria. Moreover, after silver depletion, films retain some antimicrobial activity, thanks to ammonium groups of the copolymer. We also show that the antibacterial activity of the films can then be easily re-boosted. [less ▲]

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See detailA robust antibacterial coating for stainless steel
Faure, Emilie ULg; Charlot, Aurélia; Sciannaméa, Valérie et al

Conference (2010, March 23)

Because of corrosion, chemical resistance, relevant mechanical and esthetical properties, stainless steel is widely used in the daily life, not only in the building industry but also in the food industry ... [more ▼]

Because of corrosion, chemical resistance, relevant mechanical and esthetical properties, stainless steel is widely used in the daily life, not only in the building industry but also in the food industry, the appliances or in the medical field, including implants in orthopedic surgery. However, stainless steel is unable to prevent bacteria from adhering, proliferating and forming a resistant biofilm. Therefore, surface modification is needed for providing the metal surface with antibacterial properties. The scientific literature is very rich in describing various methods for imparting antibacterial properties to different inorganic supports. However, the activity of the coating is generally time limited by the diffusion of the biocide in the environment. Novel robust and stable antibacterial coatings on stainless steel are thus highly desirable for the durability of the functionality. In this communication, we report on an all-in-one approach to prepare robust antimicrobial films on stainless steel using the layer-by-layer deposition of polyelectrolytes. Novel biocidal multilayered polyelectrolyte films in which the polycationic layer is silver loaded and bears 3,4-dihydroxyphenylalanine (DOPA), known as a promoter of adhesion to inorganic surfaces, were deposited onto stainless steel. DOPA was incorporated in the polycationic chains by radical copolymerisation of N-methacrylated DOPA with the commercially available quaternary ammonium salt of 2-(dimethylamino)ethyl methacrylate (DMAEMA+). Polystyrene sulfonate (PSS) was the polyanionic constituent of the films. In order to boost the antibacterial activity of the polycationic layer, AgNO3 was added to the aqueous solution of P(DOPA)-co-P(DMAEMA+), which resulted in the in-situ formation of silver based nanoparticles (Ag° and AgCl) that are sources of biocial Ag+. The layer-by-layer deposition of aqueous P(DOPA)-co-P(DMAEMA+)/AgCl/Ag0 suspension and aqueous solution of PSS provides stainless steel with high antibacterial activity against Gram-negative E. Coli bacteria. Moreover, after silver depletion, films retain some antimicrobial activity, thanks to the ammonium groups of the copolymer. We will also show how the antibacterial activity of the films can then be easily re-boosted. The multi-functionality of the P(DOPA)-co-P(DMAEMA+) is a key issue in this process (i) the DOPA co-units are anchored to stainless steel, (ii) these co-units reduce partly AgNO3 into Ag0 nanoparticles and stabilize them by chelation, (iii) the chloride counter-anions react with AgNO3 by ionic exchange, leading to the in situ formation of AgCl particles, and (iv) the ammonium groups are responsible for permanent antibacterial activity. Besides the advantage of the all-in-one process, another major advantage of the approach proposed here is the implementation of the whole process of film formation, including the synthesis of P(DOPA)-co-P(DMAEMA+), in aqueous media under very mild conditions. It makes the strategy very attractive for industrial scaling-up and sustainability applications. [less ▲]

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See detailNanocoatings of inorganic surfaces by molecular biomimetic
Vreuls, Christelle ULg; Genin, Alexis ULg; Zocchi, Germaine ULg et al

Poster (2010, March 22)

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See detailInorganic-binding peptides as tools for surface quality control
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Genin, Alexis ULg et al

in Journal of Inorganic Biochemistry (2010)

This paper highlights an innovative application of inorganic-binding peptides as quality control tools for detecting defects on inorganic surfaces of any shape. The approach involves attaching a ... [more ▼]

This paper highlights an innovative application of inorganic-binding peptides as quality control tools for detecting defects on inorganic surfaces of any shape. The approach involves attaching a fluorescent label to an inorganic-binding peptide and exploiting the peptide's high binding specificity to detect, by simple fluorescence microscopy, chemical composition defects of microm size and crystallographic state defects. Proof of concept was demonstrated by monitoring binding of a previously isolated ZnO-binding peptide to galvanized steel substrates. The approach was further validated for TiO(2) coatings and stainless steel, with two new, specific inorganic-binding peptides isolated by phage display. [less ▲]

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See detailPrevention of bacterial biofilms by covalent immobilization of peptides onto plasma polymer functionalized substrates
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Thierry, Benjamin et al

in Journal of Materials Chemistry (2010), 20

In this study, robust antibacterial coatings were created on stainless steel through the covalent grafting of antibacterial peptides onto an organic-polymeric interlayer deposited by RF-glow discharge ... [more ▼]

In this study, robust antibacterial coatings were created on stainless steel through the covalent grafting of antibacterial peptides onto an organic-polymeric interlayer deposited by RF-glow discharge plasma. X-Ray photoelectron spectroscopy was used to characterize and optimize the two steps of the coating process. The biocidal activity of these surfaces was demonstrated against both Gram+ and Gram- bacteria using ISO tests. 3 to 6 log10 reductions of both Gram+ and Gram- bacterial strains were obtained compared to uncoated stainless steel and depending on the particular antibacterial peptide immobilized. Importantly the antibacterial surfaces were resistant to several cleaning conditions. The latter is significant as the stability of such antibacterial surfaces in close to real life conditions is a major concern and leaching, de-lamination, rearrangement and ageing of the coating can lead to insufficient long term biofilm resistance of the surface. [less ▲]

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See detailBiomolecules in multilayer film for antimicrobial and easy-cleaning stainless steel surface applications
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Garitte, Geoffrey ULg et al

in Biofouling (2010), 26(6), 645-656

Microorganisms are able to attach to, grow on, and ultimately form biofilms on a large variety of surfaces, such as industrial equipment, food contact surfaces, medical implants, prostheses and operating ... [more ▼]

Microorganisms are able to attach to, grow on, and ultimately form biofilms on a large variety of surfaces, such as industrial equipment, food contact surfaces, medical implants, prostheses and operating rooms. Once organized into biofilms, bacteria are difficult to remove and kill, which increases the risk of cross-contamination and infection. One way to address the problem may thus be to develop antibacterial, anti-adhesion, ‘easy cleaning’ surfaces. In this study, stainless steel (SS) surfaces with antibacterial properties were created by embedding several antimicrobial peptides in a multilayer film architecture. The biocidal effect of these surfaces was demonstrated against both Gram-positive and Gram-negative bacteria according to two ISO tests. Also, coating SS surfaces with either mucin or heparin led to a reduction of <i>S. epidermidis</i> adhesion of almost 95% <i>vs</i> the bare substratum. Finally, by combining both antibacterial and anti-adhesion biomolecules in the same multilayer film, SS surfaces with better cleanability were produced. This surface coating property may help to delay the buildup of a dead bacterial layer which is known to progressively reduce exposure of the coating, leading to an undesirable decrease in the antibacterial effect of the surface. [less ▲]

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See detailMultifunctional coatings
Van de Weerdt, Cécile ULg; Detrembleur, Christophe ULg; Charlot, Aurelia et al

Patent (2009)

Detailed reference viewed: 39 (21 ULg)
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See detailMultifunctional coatings
Van de Weerdt, Cécile ULg; Detrembleur, Christophe ULg; Jérôme, Robert ULg et al

Patent (2009)

New polyelectrolyte copolymer, composite material, multilayer film and substrate carrying such polyelectrolyte copolymer, composite and multilayer film wherein the polyelectrolyte copolymer comprises a) a ... [more ▼]

New polyelectrolyte copolymer, composite material, multilayer film and substrate carrying such polyelectrolyte copolymer, composite and multilayer film wherein the polyelectrolyte copolymer comprises a) a first type of identical or different units (A) each comprising one or more dihydroxyphenyl groups such that sidechains are present along the backbone of the polyelectrolyte copolymer which contain at least one dihydroxyphenyl group each; and (b1) a second type of identical or different units (B1) each comprising a cationic moiety, or (b2) a second type of identical or different units (B2) each comprising an anionic moiety. [less ▲]

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See detailAll-in-one strategy for the fabrication of antimicrobial biomimetic films on stainless steel
Charlot, Aurélia; Sciannamea, Valérie; Lenoir, Sandrine et al

in Journal of Materials Chemistry (2009), 19

Here we report on an all-in-one approach to prepare robust antimicrobial films on stainless steel. The strategy is based on the layer-by-layer deposition of polyelectrolytes. A polycationic copolymer ... [more ▼]

Here we report on an all-in-one approach to prepare robust antimicrobial films on stainless steel. The strategy is based on the layer-by-layer deposition of polyelectrolytes. A polycationic copolymer bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) was synthesized and co-deposited with precursors of silver nanoparticles as the first layer. The presence of DOPA units ensures a strong anchoring on the stainless steel substrate, and the silver nanoparticles are sources of biocidal Ag+, providing stainless steel with antimicrobial activity. We show that multilayered films, obtained by alternating this nanoparticle-loaded polycationic copolymer with polystyrene sulfonate, a commercial polyanion, results in stainless steel with high antibacterial activity against Gram-negative E. coli bacteria. The polycationic layers are a reservoir of Ag+ that can be reactivated after depletion. The whole process of film formation, including the synthesis of the copolymer, is conducted in aqueous media under very mild conditions, which makes it very attractive for industrial scale-up and sustainable applications. [less ▲]

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See detailNanocoatings of inorganic surfaces by the layer by layer (LbL) technology
Faure, Emilie ULg; Zocchi, Germaine ULg; Lenoir, Sandrine et al

Poster (2009, April 02)

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See detailToward a Definition of X-ray Crystal Quality
Maes, Dominique; Evrard, Christine ULg; Gavira, Jose et al

in Crystal Growth & Design (2008), 8(12), 4284-4290

Crystal X-ray quality is usually evaluated by looking at data quality parameters such as (relative) Wilson B-factor, resolution, R-factors, signal-to-noise ratio, and others. As these parameters are ... [more ▼]

Crystal X-ray quality is usually evaluated by looking at data quality parameters such as (relative) Wilson B-factor, resolution, R-factors, signal-to-noise ratio, and others. As these parameters are correlated, most studies focus on one or two of them. As part of a study of the effects of microgravity on X-ray quality, full data sets of 35 ferritin crystals (17 PromISS-4 “space” crystals and 18 from the ground control) were collected. Sixty-three parameters commonly used as indicative of X-ray data quality taken from the output of the processing, scaling, and merging software packages were analyzed. This highly dimensional “quality parameter dataset” was reduced using a principal component analysis. About 78% of the variability in the data set could be explained with the first four principal components. A score-plot in this four-dimensional space clearly showed two tendencies, one for the crystals grown in space and one for the ground crystals. The differences between the two groups are observed irrespective of the software package. They can be attributed to the first principal component and reflect the superior quality of the space crystals. [less ▲]

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See detailTIM crystals grown by capillary counterdiffusion: Statistical evidence of quality improvement in microgravity
Evrard, Christine ULg; Maes, D.; Zegers, I. et al

in Crystal Growth & Design (2007), 7(11), 2161-2166

The capillary counterdiffusion method is a very efficient crystallization technique for obtaining high-quality protein crystals. This technique requires a convection-free environment, which can be ... [more ▼]

The capillary counterdiffusion method is a very efficient crystallization technique for obtaining high-quality protein crystals. This technique requires a convection-free environment, which can be achieved using either gelled solutions, very thin capillaries, or microgravity conditions. To study the influence of a convection-free environment on protein crystal quality and to evaluate two different experimental implementations to achieve it, we have made a comparative analysis of crystals grown by capillary counterdiffusion in agarose, a convective-free environment on Earth, and crystals grown in microgravity at the International Space Station. Thermotoga maritima triose phosphate isomerase (TIM) was chosen as a model for this study. The statistical analysis reveals a significant improvement for the crystals grown in microgravity in terms of their R-merge, B-value, and mosaicity, but the statistical evidence is insufficient to show a similar benefit for the resolution and mean intensity parameters. These results are quite surprising because it is known that, unlike gels, the noisy microgravity scenario offered by the ISS cannot sustain a convection-free environment on the time scale of days required for protein crystallization experiments. [less ▲]

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See detailNanocoatings of steel surfaces by molecular biomimetic
Vreuls, Christelle ULg; Charlot, Aurelia; Farina, Fabrice ULg et al

Scientific conference (2007, June 01)

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See detailProtein crystallisation under microgravity conditions: What did we learn on TIM crystallisation from the Soyuz missions?
MAES, D.; DECANNIERE, K.; ZEGERS, I. et al

in Microgravity Science and Technology (2007), XIX(5/6), 90-94

The protein Triose Phosphate Isomerase from the hyperthermophilic organism Thermotoga maritima was crystallised on board of the International Space Station in the framework of the Soyuz missions. In this ... [more ▼]

The protein Triose Phosphate Isomerase from the hyperthermophilic organism Thermotoga maritima was crystallised on board of the International Space Station in the framework of the Soyuz missions. In this paper we report on the scientific results obtained during these flights. Firstly it qas shown that different crystal forms for the same protein in the same crystallisation conditions, what is presumably due to a change in the rate at which supersaturation is achieved. Secondly, the X-ray qualité of the crystals grown in the ISS is superior to their ground control crystals. Mimicking microgravity on ground, by adding a small amourt of gel to avoid convection, also results in an improvement of X-ray quality. Nevertheless our analysis shows that the crystals obtained in this gelled ground environment are of inferior quality as compared to their space homologues. Finally we observed movement of crystals grown in the International Space Station, not only because of g-jitters but also due to residual accelerations. This has an important effect on concentration gradients of precipiants and therefore on the solubility of the protein. [less ▲]

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