Evaluation des propriétés anti-adhésives et biocides de films nanocomposites avec inclusions d'argent, déposés sur acier inoxydable par procédé plasma

Abstract : In the biomedical domain and the food industry, microbial adhesion to surfaces generates multiple negative consequences, in terms of human health, hygiene and safety of processed food. In this context, our approach is based on developing a 316L stainless steel surface treatment, to prevent microbial colonization. The surface modifications, mediated by chemical or physical treatment, did not promote Saccharomyces cerevisiae detachment, evaluated in vitro using a shear stress flow chamber. The interactions between the microbial surface and metallic elements of the passive film were hypothesized to play a predominant role in this strong adhesion. An original and dual strategy, based on a plasma process associating hexamethyldisiloxane polymerization and silver target bombardment in an asymmetrical radiofrequency discharge, was carried out and optimized. Stainless steel surfaces were thus coated with nanocomposite thin films (~ 175 nm), composed of an organosilicon matrix, exhibiting anti-adhesive properties towards S. cerevisiae, in which were embedded silver nanoparticles, displaying a high antimicrobial reactivity. A large set of complementary analytical techniques, operating at different scales, was used to correlate nanocomposite film characteristics with their anti-adhesive and antimicrobial efficiency. A total inhibition of yeast cell adhesion was achieved, by increasing the matrix polar character, through oxygen addition during the plasma process. In parallel, a 1.9 log reduction in viable counts was achieved for sessile yeast cells. Further experiments were dedicated to the thorough understanding of cellular changes induced by silver release. A deterioration of the secondary structure of proteins (cell wall, intracellular), combined with ultra-structure alterations, was observed. In addition, the biocide activity of the nanocomposite film was confirmed against two prokaryotic models (Staphylococcus aureus and Escherichia coli). The necessity of a direct contact between microorganisms and coating was demonstrated for a maximal antimicrobial efficiency. Lastly, the durability of the coating properties was assessed through a repeated use of the nanocomposite films. A decrease in the antifungal activity, coupled to an anti-adhesive property enhancement, was noticed and explained by the silver release during the first use.
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https://hal-agroparistech.archives-ouvertes.fr/tel-01562895
Contributor : Claire Saulou-Bérion <>
Submitted on : Monday, July 17, 2017 - 10:55:47 AM
Last modification on : Monday, July 15, 2019 - 2:20:04 PM
Long-term archiving on : Saturday, January 27, 2018 - 3:06:12 AM

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  • HAL Id : tel-01562895, version 1

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Claire Saulou-Berion. Evaluation des propriétés anti-adhésives et biocides de films nanocomposites avec inclusions d'argent, déposés sur acier inoxydable par procédé plasma. Microbiologie et Parasitologie. Institut National des Sciences Appliquées de Toulouse, 2009. Français. ⟨tel-01562895⟩

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