Additives for Efficient Biodegradable Antifouling Paints

The evolution of regulations concerning biocidal products aims to increase protection of the environment (e.g., EU Regulation No 528/2012) and requires the development of new non-toxic anti-fouling (AF) systems. The development of these formulations implies the use of ingredients (polymers, active substances, additives) that are devoid of toxicity towards marine environments. In this context, the use of erodable antifouling paints based on biodegradable polymer and authorized biocides responds to this problem. However, the efficiency of paints could be improved by the use of specific additives. For this purpose, three additives acting as surface modifiers were studied (Tween 80, Span 85 and PEG-silane). Their effects on parameters involved in antifouling efficiency as hydrophobicity, hydration and copper release were studied. Results showed that the addition of 3% of additives modulated hydrophobicity and hydration without an increase of copper release and significantly reduced microfouling development. Efficient paints based on biodegradable polymer and with no organic biocide could be obtained by mixing copper thiocyanate and additives

Potential antifouling properties of copper loaded zeolites on fouling diatoms

International audienc

Evaluation of anti-microfouling activity of marine paints by microscopical techniques

International audienc

Development of hybrid antifouling paints.

International audienc

Influence of Biodegradable Polymer Properties on Antifouling Paints Activity

The development of new antifouling paints requires understanding the parameters involved in antifouling activity and to develop new analytical tools for their evaluation. A series of biodegradable poly(ε-caprolactone-co-δ-valerolactone) copolymers varying by molecular weight and composition were synthesized, characterized and formulated as antifouling paints. The physico-chemical properties such as hydration, degradation, erosion and lixiviation of paints were studied. Microfouling (bacteria and microalgae) was observed by microscopic observations in a short delay, whereas macrofouling colonization was observed by visual inspection during one year. The antifouling activity of paints was modified by varying the composition and molecular weight of copolymer. The crystallinity appears to play a major role in antifouling activity, however the involvement of other properties such as hydration, degradation or erosion remains difficult to understand. Confocal laser scanning and scanning electron microscopes were used for the evaluation of antifouling paints. Results show that microalgae seem to be a pertinent indicator of antifouling activity

Surface plasma treatment (Ar/CF4) decreases biofouling on polycarbonate surfaces

International audienceThe purpose of this study was to examine the impact of hydrophobicity, surface chemistry, and topography on bacterial and microalgal adhesion. To this end, the effects of surface plasma treatments (Argon and Tetrafluorocarbon) of polycarbonate substrates on bioadhesion were investigated in vitro. Surfaces were characterized by goniometry, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Two marine bacterial strains, a hydrophobic Pseudoalteromonas sp. 5M6 and a hydrophilic Paracoccus sp. 4M6 and two microalgae (Cylindrotheca closterium and Porphyridium purpureum) involved in marine biofouling were selected. Their adhesion on the substrates was observed and quantified using confocal laser scanning microscopy-microfluidic flow-cells. It was demonstrated that the combination of three parameters, namely surface energy, fluorination, and nanotopography, significantly decreases the adhesion of three microorganisms out of four (Pseudoalteromonas sp. 5M6, Cylindrotheca Closterium, and Porphyridium purpureum) whereas one parameter on its own is insufficient

Evaluation of antibacterial activity against Salmonella Enteritidis.

International audienceSalmonella enterica serovar Enteritidis is a well-known pathogenic bacterium responsible for human gastrointestinal enteritis mainly due to the consumption of eggs and egg-products. The first aim of this work was to study several virulence factors of a strain isolated from egg content: SEovo. First, bacterial growth was studied at several temperatures and cell morphology was observed by scanning electronic microscopy. These experiments showed Salmonella's ability to grow at low temperatures and to produce exoproducts. Next, Salmonella motility was observed performing swimming, twitching, and swarming tests. Results indicated a positive flagellar activity and the cell ability to differentiate and become hyperflagellated under specific conditions. Moreover, SEovo adherence and biofilm formation was carried out. All of these tests enabled us to conclude that SEovo is a potential pathogen, thus it can be used as a model to perform antibacterial experiments. The second part of the study was dedicated to the evaluation of the antibacterial activity of different molecules using several methods. The antibacterial effect of silver and copper aluminosilicates was tested by two different kinds of methods. On the one hand, the effect of these two antibacterial agents was determined using microbiological methods: viable cell count and agar-well diffusion. And on the other hand, the antibacterial activity was evaluated using CLSM and SYTO Red/SYTOX Green dyeing. CLSM allowed for the evaluation of the biocide on sessile cells, whereas the first methods did not. Results showed that adhered bacteria were more resistant than planktonic counterparts and that CLSM was a good alternative to evaluate antibacterial activity on fixed bacteria without having to carry out a removing step

Influence of biocides and algal extracts on adhesion and biofilm formation of marine bacteria

International audienceAny surface immersed in aqueous environment is rapidly colonized by micro and macroscopic organisms [1]. This phenomenon is known as biofouling, which is the origin of complex and recurring point in the global economy and environmental problems. The recent ban of ecotoxic products, used to counteract this phenomenon, generates the interest for research of new antifouling molecules, more environmentally friendly. The objective of this study is to evaluate the potential fouling of microalgae extracts compared to commercial biocides. In this study, the effectiveness of antifouling molecules are evaluated by the adhesion and primary biofilm formation of three pioneering marine bacterial strains. Bacteria were grown at 20 °C. The anti-adhesive activity is evaluated in a static system, by microplates [2] and in a dynamic system, by flow cell. Culture was performed on glass slides in the chambers of the flow cell, adhesion was allowed for 3 hours and a flow of culture environment was applied for up to 48 hours to obtain a biofilm formation. Bacteria are dyed by Syto61 and were observed with a confocal microscopy laser scanning. The effective concentration of commercial biocides, which allows attachment of 50% of bacteria, is between 5 and 18 µM, depending on the bacteria and the biocide. Concerning the extracts of H2O-MeOH (1:1) and MeOH100% of microalgae revealed an inhibition of adhesion and biofilm formation. The microalgal extracts with antifouling activity is analyzed by Hr-MAS to identify the molecules responsible for this activity. The perspectives of this work are to target microalgal strains which can be qualitative sources of biocides withhigh efficiency.This will serve as a basis for developing new antifouling coatings that can be used in temperate and tropical ecosystems

Non-Leachable Hydrophilic Additives for Amphiphilic Coatings

Amphiphilic surfaces are particularly effective at inhibiting the adhesion of microorganisms (bacteria, cells, microalgae, etc.) in liquid media. The aim of this study is to determine the best hydrophilic linker to promote bonding between poly(ethylene glycol) (PEG) as a hydrophilic additive and poly(dimethyl siloxane) (PDMS) as the hydrophobic matrix. Various parameters have been studied (molecular weight, linker type, and polymer end-group), as well as the efficiency of the linking, the capacity of PEG to access to the surface of the film, and overall film homogeneity. According to the results, a PDMS linker paired with a PEG moiety allows for compatibilization of the compounds during cross-linking. This compatibilization seems to provide a good bonding with the matrix and a good surface access to the hydrophilic moiety. Therefore, this structure comprising a linking function attached to the PDMS–PEG copolymer has high potential as a non-releasable additive for amphiphilic coating applications