摘要 :
The inactivation of bacteria and biomolecules using plasma discharges were investigated within the European project BIODECON. The goal of the project was to identify and isolate inactivation mechanisms by combining dedicated beam ...
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The inactivation of bacteria and biomolecules using plasma discharges were investigated within the European project BIODECON. The goal of the project was to identify and isolate inactivation mechanisms by combining dedicated beam experiments with especially designed plasma reactors. The plasma reactors are based on a fully computer-controlled, low-pressure inductively-coupled plasma (ICP). Four of these reactors were built and distributed among the consortium, thereby ensuring comparability of the results between the teams. Based on this combined effort, the role of UV light, of chemical sputtering (I.e. the combined impact of neutrals and ions), and of thermal effects on bacteria such as Bacillus atrophaeus, Aspergillus niger, as well as on biomolecules such as LPS, Lipid A, BSA and prions have been evaluated. The particle fluxes emerging from the plasmas are quantified by using mass spectrometry, Langmuir probe measurements, retarding field measurements and optical emission spectroscopy. The effects of the plasma on the biological systems are evaluated using atomic force microscopy, ellipsometry, electrophoresis, specially-designed western blot tests, and animal models. A quantitative analysis of the plasma discharges and the thorough study of their effect on biological systems led to the identification of the different mechanisms operating during the decontamination process. Our results confirm the role of UV in the 200-250 nm range for the inactivation of microorganisms and a large variability of results observed between different strains of the same
species. Moreover, we also demonstrate the role of chemical sputtering corresponding to the synergism between ion bombardment of a surface with the simultaneous reaction of active species such as O, O_2 or H. Finally, we show that plasma processes can be efficient against different micro-organisms, bacteria and fungi, pyrogens, model proteins and prions. The effect of matrices is described, and consequences for any future industrial implementation are discussed.
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摘要 :
Research into nanostructured thin films of plasma polymers is driven by applications of these materials in a wide variety of fields. Here, we review work on the preparation of such coatings using low-pressure discharges, with a fo...
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Research into nanostructured thin films of plasma polymers is driven by applications of these materials in a wide variety of fields. Here, we review work on the preparation of such coatings using low-pressure discharges, with a focus on the different strategies employed. We start with nanostructured plasma polymers prepared by plasma polymerization under special conditions such as at a large distance from the plasma zone and at a high working gas pressure. Then, methods based upon plasma etching and colloidal lithography combined with plasma treatment are described. Finally, dusty plasmas and gas aggregation cluster sources with planar magnetrons are considered for generation of nanoclusters, nanoparticles, and for deposition of nanostructured plasma polymer films.
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Strategy that enables production of nanostructured surfaces is presented. Investigated method is a two-step process based on overcoating of nanoparticles produced by a gas aggregation source by thin film of magnetron sputtered pol...
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Strategy that enables production of nanostructured surfaces is presented. Investigated method is a two-step process based on overcoating of nanoparticles produced by a gas aggregation source by thin film of magnetron sputtered polytetrafluoroethylene. It is shown that surfaces with spatially nonhomogeneous wettability may be produced in this way.
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This study is focused on the evaluation of resistance of plasma polymers toward common sterilization techniques, i.e. property important for possible use of such materials in biomedical applications. Three kinds of plasma polymers...
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This study is focused on the evaluation of resistance of plasma polymers toward common sterilization techniques, i.e. property important for possible use of such materials in biomedical applications. Three kinds of plasma polymers having different bioadhesive natures were studied: plasma polymerized poly(ethylene oxide), fluorocarbon plasma polymers, and nitrogen-rich plasma polymers. These plasma polymers were subjected to dry heat, autoclave and UV radiation treatment Their physical, chemical and bioresponsive properties were determined by means of different techniques (ellipsometry, atomic force microscopy, wettability measurements. X-ray photoelectron spectroscopy and biological tests with osteoblast-like cells MG63). The results clearly show that properties of thin films of plasma polymers may be significantly altered by a sterilization process. Moreover, observed changes induced by selected sterilization methods were found to depend strongly on the sterilized plasma polymer.
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Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characteriz...
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Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.
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Deposition of Cu nanoclusters produced by compact gas aggregation nanocluster source without size filtration is investigated. The main emphasis is given to the determination of influence of operating conditions (pressure in the ag...
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Deposition of Cu nanoclusters produced by compact gas aggregation nanocluster source without size filtration is investigated. The main emphasis is given to the determination of influence of operating conditions (pressure in the aggregation and deposition chambers, magnetron current) on deposition rate of Cu nanoclusters as well as on the evaluation of their size distribution and chemical structure. Subsequently, possibility to employ this nanocluster source for fabrication of Cu nanodusters/plasma polymer multilayer nanocomposites was tested. It is shown that by step-by-step deposition of layers of Cu nanoclusters and plasma polymer it is possible to control not only amount of Cu nanoclusters incorporated into plasma polymer, but also roughness, wettability and optical properties of resulting coatings without affecting their surface chemical composition.
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Vacuum-based strategy for production of super-hydrophilic nanostructured SiO_x coatings on conventional polymers was developed. This method is based on pre-seeding of polymers with Ag nanoparticles fabricated by means of gas aggre...
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Vacuum-based strategy for production of super-hydrophilic nanostructured SiO_x coatings on conventional polymers was developed. This method is based on pre-seeding of polymers with Ag nanoparticles fabricated by means of gas aggregation source of nanoparticles prior to the SiO_x deposition. It is shown that at a sufficiently large amount of Ag nanoparticles the produced coatings exhibited nanotexture that possessed temporally stable super-hydrophilic character with water contact angles lower than 10° for a period of 2 years.
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The mechanical stability of nanoclusters embedded in nanocomposite coatings was investigated by scratch and wear tests supported by atomic force microscopy using surface topography mode. Titanium and plasma polymer nanoclusters we...
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The mechanical stability of nanoclusters embedded in nanocomposite coatings was investigated by scratch and wear tests supported by atomic force microscopy using surface topography mode. Titanium and plasma polymer nanoclusters were deposited on planar substrates (glass, titanium) using a magnetron-based gas aggregation cluster source. The deposited clusters were overcoated with a thin titanium film of different thicknesses to stabilize the position of the clusters in the nanocomposite coating. Nanotribological measurements were carried out to optimize the thickness of the overcoating film for sufficient interfacial adhesion of the cluster/film system.
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The films of Pt nanoclusters were deposited by means of gas aggregation cluster source. At pressure of 100 Pa in the aggregation chamber and magnetron current of 0.2 A, highly porous films of metallic Pt clusters having average di...
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The films of Pt nanoclusters were deposited by means of gas aggregation cluster source. At pressure of 100 Pa in the aggregation chamber and magnetron current of 0.2 A, highly porous films of metallic Pt clusters having average diameter of 4 nm are deposited as witnessed by transmission electron microscopy and X-ray diffraction. The deposition rate as measured by spectroscopic ellipsometry is approximately 1 nm/s. These results are promising in respect to possible use of this deposition technique for the fabrication of nanocomposite materials for diverse technological applications.
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摘要 :
Cleaning, sterilization and decontamination of medical equipment are fundamental steps in health care facilities. However, the techniques currently used are often insufficient to guarantee complete inactivation or elimination of v...
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Cleaning, sterilization and decontamination of medical equipment are fundamental steps in health care facilities. However, the techniques currently used are often insufficient to guarantee complete inactivation or elimination of various pathogens; this represents a serious problem with respect to the possible transmission of diseases or onset of immunological events by the residues left after incomplete decontamination. Therefore, there is a demand for developing alternative decontamination methods allowing entire elimination of all biological residues from the surfaces of medical tools.
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