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International audience; An enzymatic biofuel cell cathode was elaborated by nano-structuration and functionalization of graphite using two consecutive plasma treatments before immobilization of laccase as a biocatalyst to perform oxygen reduction reaction (ORR) by direct electron transfer ((DET). Nano-structuration of graphite surfaces by synthesis of vertical graphen-like carbon nanowalls (CNWs) was performed by microwave excited plasma enhanced chemical vapor deposition (PECVD). Atmospheric pressure plasma jet (APPJ) system was then used to functionalize chemically the CNWs surface via a rapid and dry route. A partial fractional design evidenced two significant parameters of the APPJ treatment in terms of ORR current density: the treatment time and the inter-distance between the plasma jet and the surface of the carbon material. With the optimized APPJ treatment parameters, a four-fold enhancement of the ORR current density (-440 ± 70 µA/cm2) could be obtained on CNWs, compared to graphite electrodes. The best current density obtained was about −1 mA/cm2 with oxidized laccase covalently immobilized on the electrode without any agitation of the solution, confirming the main importance of enzyme orientation on the electrode surface for efficient DET transfer, the relevance of electrode nanostructuration and the advantage of covalent linking of the protein on the electrode surface.

International audience; Hexamethyldisiloxane (HMDSO)/Graphene nanosheets (GNs) nanocomposite coatings were deposited by a dielectric barrier discharge at atmospheric pressure. Commercially available GNs were incorporated into HMDSO precursor at different concentrations up to 2 wt%. The nanocomposite coatings were analyzed using scanning electron microscopy (SEM) and nanoindentation test. Based on SEM images, it was found that the GNs were well distributed and dispersed in the plasma polymerized hexamethyldisiloxane (ppHMDSO) matrix with no significant agglomeration. The results of nanoindentation tests performed with the continuous stiffness measurements mode showed an increase in the hardness and reduced Young's modulus with the increase of graphene nanosheets percentage. The maximum increase was two orders of magnitude for 2% GNs/ppHMDSO nanocomposite coatings compared to the homopolymer ppHMDSO. Furthermore, the creep compliance analysis showed that the nanocomposite coatings exhibited a viscoelastic behavior compared to the plasma polymer homopolymer.

www.springerlink.com; International audience; We report a method to obtain biocompatible PEG copolymer coatings inside High Density Polyethylene (HDPE) and Pyrex tubes, which was successfully developed by using a transporting discharge. The latter being a dry process, it is easier to apply as compared to the conventional multistep wet chemical techniques. The results presented in this paper show that for a 70 cm tube good cell repellent properties as compared to the control was obtained for the entire length of the tube. The best nonfouling properties with respect to CT-26 (colon cancer) were obtained for coatings presenting the best retention of ether functionalities from the DEGME monomer i.e. between 5-25 cm downstream of the tube. These results are interesting for surface modification of biomaterial and biomedical devices which present hollow bodies.

"The final publication is available at link.springer.com"; International audience; In this research work we demonstrated that a helium/oxygen Dielectric Barrier Discharge conferred hydrophilic functional groups onto the surface, which lead to enhanced bioactivity of UHMWPE without affecting the biocompatibility of the polymer. The latter was checked by increased adhesion of fibroblast cells to the polymer. The effects of the He/2% O2 DBD plasma was compared for the first time to a rotating blown arc atmospheric pressure plasma jet (r-APPJ) in air. The results show a better functionalization as well as stability of the surface properties of the films treated with the DBD. The surface modified UHMWPE once immersed in a Simulated Body Fluid induced the formation of nucleus of hydroxyapatite (calcium phosphate) leading to the growth of a thick apatite coating which was followed up to 14 days, which can be expected to be highly bioactive. Surface characterization techniques also showed different chemical moieties in the case of the two different atmospheric discharges. DBD discharge in He/2% O2, leading to more stable polar functions grafted to a crosslinked polymer surface, proved to be more bioactive than UHMWPE treated by a r-APPJ in air. The latter treatment lead to grafting of less oxygen containing groups to the surface as well as to LMWOM created on r-APPJ treated UHMWPE which are unstable in aqueous media used both in SBF and fibroblasts in DMEM.

Plasma processing finds widespread biomedical applications, such as the design of biosensors, antibiofouling surfaces, controlled drug delivery systems, and in plasma sterilizers. In the present coronavirus disease (COVID‐19) situation, the prospect of applying plasma processes like surface activation, plasma grafting, plasma‐enhanced chemical vapor deposition/plasma polymerization, surface etching, plasma immersion ion implantation, crosslinking, and plasma decontamination to provide timely solutions in the form of better antiviral alternatives, practical diagnostic tools, and reusable personal protective equipment is worth exploring. Herein, the role of nonthermal plasmas and their contributions toward healthcare are timely reviewed to engage different communities in assisting healthcare associates and clinicians, not only to combat the current COVID‐19 pandemic but also to prevent similar kinds of future outbreaks., This review presents a comprehensive take on the significance of nonthermal plasma processing as a versatile tool for developing state‐of‐the‐art biomedical and healthcare technologies. Under the spotlight is its immense technological potential to offer apposite solutions for combating viral pandemics like coronavirus disease (COVID‐19), be it in the form of rapid diagnostic tools fabrication, sterilized personal protective equipments (PPEs), drug delivery systems, or antimicrobial and antibiofouling surfaces.

Background It may be impossible to perform cancer surgery with free margins in the presence of an unresectable structure. Local drug treatment after surgery has been proposed to increase the rate of tumor control. Methods Multi-nanolayers (10-330 nm) were generated by a low-pressure (375mTorr) inductively coupled plasma (13.56 MHz) reactor for anticancer drug delivery by the deposition of polycaprolactone-polyethylene glycol multistack barrier on the collagen membrane (100 μm thickness). Carboplatin (300 μg/cm2) was used for the in vitro and in vivo investigations. Energy-dispersive X-ray spectroscopy (15 keV), scanning electron microscopy and inductively coupled plasma mass spectrometry were used to detect the presence of carboplatin in the nanolayer, the tumor sample and the culture medium. Preclinical studies were performed on ovarian (OVCAR-3NIH) and colon (CT26) cancer cell lines as xenografts (45 days) and allografts (23 days) in Swiss-nude (n = 6) and immunocompetent BALB/cByJ mice (n = 24), respectively. Results The loading of carboplatin or other drugs between the nanofilm on the collagen membrane did not modify the mesh complex architecture or the drug properties. Drugs were detectable on the membrane for more than 2 weeks in the in vitro analysis and more than 10 days in the in vivo analysis. Cytotoxic mesh decreased cell adherence (down 5.42-fold) and induced cancer cell destruction (up to 7.87-fold). Implantation of the mesh on the mouse tumor nodule modified the cell architecture and decreased the tumor size (50.26%) compared to the control by inducing cell apoptosis. Conclusion Plasma technology allows a mesh to be built with multi-nanolayer anticancer drug delivery on collagen membranes.

International audience; In this study, micrometer thick Ag‐TiO2 coatings were deposited in a single and facile step by spraying the precursor in an atmospheric pressure plasma jet with different concentrations of Ag nanoparticles. The homogenous distribution of Ag decreased the TiO 2 crystal size and increased the surface area. The coatings were characterized to be porous with an anatase phase with improved charge separation and visible light absorption. The photocatalytic activity of the materials was investigated for degrading rhodamine B using a white lamp as a screening method to optimize Ag‐TiO 2 coatings. Then the photodegradation of trace pharmaceutical compounds (TrPCs) was investigated by using a solar light simulator at the optimal condition of a TiO 2 coating with 0.4wt% Ag

International audience; A low pressure ICP plasma setup was utilized to deposit thin organic barrier coatings on various substrates to fabricate DDS with encapsulated Carboplatin as a drug and Methylene Blue as a drug model. Choice of the substrates and optimal plasma parameters were discussed for the fabrication of DDS with required characteristics. Prepared thin films were analysed by FTIR, SEM, and the barrier properties were studied by measuring drug concentration released into the medium by UV-VIS and ICP-MS techniques.

In this work, an open-air arc plasma jet has been studied to polymerize 3-aminopropyelthrietoxysilane (APTES), which is the most commonly used aminosilane to functionalize surfaces with amine groups. Although the discharge produced from air is highly oxidative and the gas temperature is high as compared to other atmospheric plasma sources, amine groups, as well as amide ones, were identified in the nanometers thick coatings by XPS and FTIR analysis. By comparing the results with post-treatment and -grafting experiments, the partial retention of amine groups might be explained by the non-ideal mixing of the precursor flow with the main gas stream inside the plasma jet. Beside the intrinsic plasma reactivity, hydrodynamics effects are indeed important when considering flowing atmospheric plasmas.

// Sudhir Bhatt 1, 3 , Fatemeh Valamanesh 2 , Jerome Pulpytel 1 , Rea Lo Dico 2 , Aliby Baiyukha 1 , Iman Al-dybiat 2 , Marc Pocard 2 , Farzaneh Arefi-Khonsari 1 , Massoud Mirshahi 2 1 Sorbonne Universites, UPMC Univ. Paris 6, CNRS, Laboratoire Interfaces et Systemes Electrochimiques, 75005, Paris, France 2 Sorbonne Paris Cite Universites, UMR Univ. Paris 7, INSERM U965 Carcinose, Angiogenese et Recherche Translationnelle, L’Hopital Lariboisiere, 75010, Paris, France 3 Current address: Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, 23508, VA, USA Correspondence to: Massoud Mirshahi, email: massoud.mirshahi@inserm.fr Keywords: plasma polymers, biodegradable coatings, in vivo drug delivery system, anti-cancer drug, targeted therapy Received: May 11, 2016 Accepted: July 19, 2016 Published: July 29, 2016 ABSTRACT A low pressure plasma process based on plasma deposition has been used to develop a drug delivery strategy. In this study, a drug delivery system based on different layers of plasma co-polymerized Poly e-caprolactone-Polyethylene glycol (PCL-PEG) co-polymers was deposited on biocompatible substrates. Cis-platinum (118 μgm/cm 2 ) was used as an anti-cancer drug and incorporated for local delivery of the chemotherapeutic agent. The co-polymer layers and their interaction with cancer cells were analyzed by scanning electron microscopy. Our study showed that the plasma-PCL-PEG coated cellophane membranes, in which the drug, was included did not modify the flexibility and appearance of the membranes. This system was actively investigated as an alternative method of controlling localized delivery of drug in vivo . The loading of the anti-cancer drug was investigated by UV-VIS spectroscopy and its release from plasma deposited implants against BALB/c mice liver tissues were analyzed through histological examination and apoptosis by TUNEL assay. The histological examination of liver tissues revealed that when the plasma-modified membranes encapsulated the cis-platinum, the Glisson’s capsule and liver parenchyma were damaged. In all cases, inflammatory tissues and fibrosis cells were observed in contact zones between the implant and the liver parenchyma. In conclusion, low pressure plasma deposited uniform nano-layers of the co-polymers can be used for controlled release of the drug in vivo.

International audience; This work is focused on synthesizing and employing one-dimensional (1D) titanium dioxide (TiO2) for hydrogen (H2) production. Based on using electron donors (EDs) (ethanol, methanol, fomic acid and 1,2,3 propanetriol), the increased H2 production, when compared to P25 TiO2 nanoparticles, was due to the large specific surface area (SSA) and enhanced electron mobility of 1D TiO2. The impact of the 1D TiO2 synthesis reaction conditions (temperature, NaOH concentration and the TiO2 precursor concentration) on the photocatalytic H2 production rate was evaluated using a 3-factor 3-level Box Behnken design (BBD). The BBD model demonstrated that the temperature and the NaOH concentration significantly affected the 1D TiO2 phase structure, crystal size, SSA, bandgap and the photocatalytic H2 production rate. The phase structure and crystal size of 1D TiO2 were key factors affecting the H2 production rate. 1D TiO2 containing an anatase phase with a mean crystal size of 20.1 ± 0.2 nm was synthesized at 126 °C, 15 M NaOH and 49 g L−1 TiO2. The maximum H2 production rate of 475 ± 12 μmol·h−1 (quantum efficiency (ε) = 20.2 ± 0.5%) for the 1D TiO2 sample was significantly enhanced when compared to commercial TiO2 P25. The H2 production rate for the optimized 1D TiO2 was significantly enhanced by decorating the structure with Pt and Au. Hydrothermal synthesized of 1D TiO2 provided an efficient and low cost method for producing H2 from ethanol, methanol, fomic acid and 1,2,3 propanetriol.

International audience; The present study proposes an alternative eco-friendly method to prepare a thin composite coating based on graphene embedded in siloxane polymers which can be used as application for the corrosion protection of steel. The nanocomposite coatings were elaborated by a dielectric barrier discharge using a nebulized colloidal suspension of graphene nanosheets (GNs) dispersed in hexamethyldisiloxane (HMDSO) used as the precursor for the polymer matrix. After obtaining a stable colloidal solution, it was nebulized into the plasma reactor to form a plasma polymer (pp) coating from HMDSO (ppHMDSO) in which GNs were incorporated (GN@ppHMDSO) on the mild steel substrate. The chemical structure of the hybrid coatings was characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometry. Raman spectra of GNs and GN@ppHMDSO coatings suggest the existence of charge transfer between the GNs and the HMDSO matrix. Furthermore, scanning electron microscopy confirms the synthesis of micro/nanocomposite with a fairly homogeneous dispersion of the GNs in the polymer matrix. The corrosion resistance of the samples was evaluated by electrochemical impedance spectroscopy which showed that the hybrid coatings GN@ppHMDSO deposited by a one-step atmospheric pressure plasma process, presented excellent anticorrosion performance with 99.99% of protection efficiency.

International audience; One-dimensional TiO2 nanostructure synthesized using a hydrothermal method showed significant differences in the bandgap energies and crystal phase properties under different synthesis conditions. The objectives of this study were to evaluate the effect of the hydrothermal reaction conditions on the bandgap energy and to optimize the reaction conditions using a 3-factor 3-level Box Behnken design. The factors investigated include temperature, NaOH concentration and TiO2 concentration (BBD). A quadratic response surface model predicted optimum conditions for the maximum and minimum bandgap energy. The BBD analysis and other statistical tools provided evidence showing the temperature and NaOH concentration significantly affected the 1D TiO2 bandgap energy. Pure anatase was associated with a higher bandgap energy, whereas the biphasic anatase-rutile and anatase-TiO2-B phases were linked with decreasing the bandgap energy. In addition, the crystal size and specific surface area (SSA) impact on the bandgap energy was due to the size quantization effect.

International audience; Enhanced TiO2 nanorods (TNRs) with partially reduced graphene oxide (RGO) (designated as GT) were prepared for degrading aqueous hazardous pollutants. The degree of RGO oxidation had an important role in affecting the photoelectronic and photocatalytic activities of GT composites. The study examined the impact of the degree of RGO oxidation on the photocatalytic activities. The photocatalytic activity of the materials was investigated for degrading rhodamine b (RhB), methyl orange (MO), methylene blue (MB), and phenol by using ultraviolet (UV) light. The highest photocatalytic activity was observed when the atomic oxygen-to-carbon (O/C) ratio of RGO was 0.130 ± 0.003. This study suggested the photocatalytic performance was maximized by preserving a selected amount of the RGO oxygen-containing groups. The work reported in this study on optimizing the RGO-based TiO2 photocatalyst could serve as a promising approach for preparing and optimizing other types of carbon-based photocatalysts such as graphene-based CdS.

STSM grant by COST ACTION MP1101 “Biomedical Applications of Atmospheric Pressure Plasma Technology” is acknowledged. Financial support by Innovaciones DisRas S.L. Company is also acknowledged.

International audience; A pulsed-arc atmospheric pressure air plasma jet has been used to depositplasma polymerized acrylic acid/methylene-bis-acrylamide (ppAA/MBA) organic thinfilms. Optical emission spectroscopy has been performed to investigate the reactivity of theplasma and the dissociation of the precursor as a function of the pulse frequency anddistance from the nozzle. An estimation of the OH rotational temperature, which is anindicator of the plasma gas temperature, has also been performed. By heating the substrateduring deposition, it was possible to improve to a great extent the stability to water of thecoatings. Stable ppAA/MBA films have been obtained with an air plasma over a largerange of pulsed frequencies (from 15 to 25 kHz) when the substrate was heated to 200° C.The composition of these coatings was investigated by FTIR and different amide/acidratios were obtained, showing the possibility to grow stable films with different functionalgroups by adjusting the deposition parameters.

There exists an abundant literature on polymers used for biomedical applications. However, the research described in this article deals with the plasma (co)polymerisation of different organic precursors for surface modifications of a variety of substrates in order to tailor the physico-chemical properties of the substrates for tuneable biomolecule–surface interactions. The major part of the work presented focuses on the low-pressure inductively excited plasma-enhanced chemical vapour deposition of organic precursors for the functionalisations of material. In the second part of the article, an open-air custom-made atmospheric-pressure dielectric barrier discharge (DBD) plasma jet is discussed for the anti-fouling applications. This special focus aims to elaborate the state of the art of different low and atmospheric pressure plasma-deposited polymers for anti-fouling applications, cell–surface interactions and tissue engineering applications.

Enhanced TiO

International audience; For targeting the cancer cells, a low pressure ICP reactor was utilised to fabricate a drug delivery system. On the surface of biocompatible collagen membranes, thin plasma polymer coatings were deposited to encapsulate an anticancer drug carboplatin and impart different biologically active functionalities. The characteristics of the deposited films were analysed by FTIR and XPS and the overall functionalities were tested by in vitro and in vivo experiments on the cancer cells lines on the cancer nodules respectively. Preliminary results of fabricated drug delivery systems showed the inhibition of cancer cell proliferation in vitro as well as tumour growth in mice models by 2.8 folds in mass compared to the control case

International audience; Quasi-one-dimensional (Q1D) titanium dioxide (TiO2) nanomaterials have attracted attention inphotocatalytic applications because of their high oxidative potential coupled with increasing activesites. In this study, Q1D TiO2 samples with different phase structure, crystal size, and specific surfacearea were produced using a hydrothermal method by varying the reaction conditions (temperature,alkaline concentration, and the TiO2 precursor concentration). A three-factor three-level Box–Behnkendesign (BBD) with three replicates (15 conditions) at the center point was employed to evaluateand optimize the hydrothermal synthesis factors in terms of photocatalysis of rhodamine B (RhB),phenol, methyl orange, and methylene blue. The BBD demonstrated that the temperature and theNaOH concentration significantly affected the Q1D TiO2 crystal size, phase structure, bandgap, andphotocatalytic activity. A reduce temperature at 120°C and a low NaOH concentration at 5 M werefavorable in producing a biphasic anatase–rutile structure with optimum photocatalytic activity.Under a higher temperature of 190°C and with ≥ 10 M NaOH concentration, the presence of TiO2-Bphase resulted in the lowest photocatalytic activity.

International audience; SiOx films were deposited using an atmospheric-pressure transporting discharge, and we adopted tetraethyl orthosilicate (TEOS) as the precursor. We studied the effects of nozzle-substrate distance, applied power, deposition time, and precursor inlet positions on the substrates placed at the tube exit. The deposited thin films were investigated using field-emission scanning electron microscopy and attenuated total-reflection Fourier-transform infrared spectroscopy. The specific studies that we carried out showed a clear relationship between the operating parameters of the deposition process and the morphological and chemical properties of the deposited films. In addition to samples treated outside of the tube in the jet mode, transporting discharge was used to deposit SiOx thin films inside fluorinated ethylene propylene (FEP) tubes. Changing the chemistry inside the FEP tubes completely modified the interaction of CT-26 cells; that is, the nonadhesive FEP tubes became completely adhesive. This study shows the potential for modifying surfaces properties inside tubes for different biological applications.

International audience; In order to obtain a durable cost-effective membrane for membrane distillation (MD) process, flat sheet polyethersulfone (PES) membranes were modified by an atmospheric pressure nonequilibrium plasma generated using a dielectric barrier discharge in a mixture of argon and hexamethyldisiloxane as the organosilicon precursor. The surface properties of the plasma-modified membranes were characterized by water contact angle (CA), liquid entry pressure, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water CA of the membrane was increased from 64° to 104° by depositing a Si(CH3)-rich thin layer. While the pristine PES membrane was not applicable in the MD process, the modified PES membrane could be applied for the first time in an air gap membrane distillation setup for the removal of benzene as a volatile organic compound from water. The experimental design using central composite design and response surface methodology was applied to study the effects of feed temperature, concentration, and flow rate as well as their binary interactions on the overall permeate flux and separation factor. The separation factor and permeation flux of the modified PES membrane at optimum conditions were comparable with those of commercial polytetrafluoroethylene membrane.

Surface activation of polymers by atmospheric pressure plasma is an economically important process for bonding technologies. Although most of the studies are focused on the modification of the surface chemistry, this study investigates the modification of the topmost surface and the deeper layers of a polyamide-6 sheet treated by an open-air atmospheric plasma jet system. The plasma jet used in this study is a unique combination of highly reactive species (e.g. O8, 8OH. . .) and a high temperature gas estimated (from 600–1 000 K) which leads to surface functionalization,amorphization and polymorphism modification. The results have shown that an amorphization of the polyamide occurs on the top surface. Moreover, a crystallization of the amorphous phase in the a form was also highlighted in the depth of the material.

Water stable plasma polymerized acrylic acid/methylene-bis-acrylamide (ppAA/MBA) thin films have been deposited with an atmospheric pressure air plasma jet, a fast technique to grow organic thin films. To increase the stability of the coatings, a cross-linking agent (MBA) was added to the precursor (AA), which was introduced with a home-made spraying system. The jet speed and pulse frequency of the discharge were investigated regarding the properties of the coatings. Two types of materials were obtained: in low energy conditions (high jet speed and low frequency) the films presented a water-soluble part with a certain organized structure. When more energy is supplied to the growing films, a more polymerized material with a more amorphous structure is obtained. Increasing the energy further leads to the deposition of a more cross-linked film with a better stability to water. In optimized conditions, no weight loss and no significant chemical change were noticed after soaking in water.

N-doped TiO2 thin films have been deposited by reactive RF magnetron sputtering at different total gas pressures and varying O 2/N2 gas flow rates at 300 C. The thin film nanostructure has been studied by scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). Increasing the deposition pressure leads to reduced crystallinity of the thin films and a higher N2 flow rate was required to incorporate N into the growing film. This is attributed to the lower energy ion bombardment of the surface and N adatom chemical reactivity being reduced at higher total gas pressures. Ar+ ion sputtering of the deposited N-doped TiO2 thin films has enabled a detailed XPS investigation of the surface and bulk N species to be performed. Adsorbed N species have been identified on all the deposited thin film surfaces, with the most prevalent adsorbed N species occurring at a binding energy of approximately 400 eV, shown to originate from atmospheric contamination, most probably N containing organic species. The bulk N content varies between 0.6 and 6.0 at.% and N is located predominantly at substitutional sites in the TiO2. The presence of interstitial N, in the form of NO species, has been identified by XPS in some thin films deposited at higher deposition pressures. Hence, varying the total gas pressure may provide a route for tailoring the location of N in the bulk structure. At higher N contents (> 3 at.%), TiN is found as a secondary phase within the bulk structure and the presence of TiN leads to a sharp reduction in the band gap. Post-deposition annealing of low N containing films results in an N-doped TiO2 single phase anatase structure. © 2013 Elsevier B.V.

International audience; N-doped TiO2 thin films have been prepared by reactive RF magnetron sputtering at different pressures and with different compositions using a dual reactive gas mixture of nitrogen and oxygen. The morphological, optical, photo-electrochemical and photocatalytic properties have been studied in order to investigate the white light and visible light photoactivities of the films. Significant control over the band gap energy in the films was achieved by varying the deposition parameters. Photoelectrochemical characterization revealed improved white light photocurrent generation in nitrogen doped films prepared at low pressures. However, the visible light photocurrent generation showed improvement for all deposition pressures, and changed accordingly with the nitrogen incorporation. Photocatalytic measurements of a common chemical pollutant NMP (N-methyl-2-pyrrolidone) under different irradiation conditions provided evidence of improved photoactivity for samples prepared at high pressure, due to the increased active surface area and optimal nitrogen doping levels. Overall, this study showed a simple method to produce highly controllable nitrogen doping in different sites within TiO2 showing improved visible light photoactivity and photo induced pollutant degradation. More interestingly, by investigating the effect of different nitrogen sites in nitrogen doped TiO2, we have shown that the optimized conditions for photocatalysis do not correspond to those for water splitting.

A custom made non-equilibrium atmospheric pressure argon plasma jet was developed for the deposition of PEG like coatings in open-air for cell repellent applications. OES and electrical measurements were performed to characterize the discharge. The emission of the N2 (C3Πu–B3Πg) was followed in order to minimize the air entry in the plasma. Surface analyses were carried out on ap-DEG coatings and the best retention of COC was obtained under mild plasma conditions. The ap-DEG coatings were compared with typical LP deposited PEG like coatings. Less retention of COC and therefore less cell repellent properties were observed for ap-DEG coatings as compared to those deposited at low pressure.

In this work, a simple and rapid method was used to functionalize carbon electrode in order to efficiently immobilize laccase for biosensor application. A stable allylamine coating was deposited using a low pressure inductively excited RF tubular plasma reactor under mild plasma conditions (low plasma power (10 W), few minutes) to generate high density amine groups (N/C ratio up to 0.18) on rough carbon surface electrodes. The longer was the allylamine plasma deposition time; the better was the surface coverage. Laccase from Trametes versicolor was physisorbed and covalently bound to these allylamine modified carbon surfaces. The laccase activities and current outputs measured in the presence of 2,2'-azinobis-(3-ethylbenzothiazole-6-sulfonic acid) (ABTS) showed that the best efficiency was obtained for electrode plasma coated during 30 min. They showed also that for all the tested electrodes, the activities and current outputs of the covalently immobilized laccases were twice higher than the physically adsorbed ones. The sensitivity of these biocompatible bioelectrodes was evaluated by measuring their catalytic efficiency for oxygen reduction in the presence of ABTS as non-phenolic redox substrate and 2,6-dimethoxyphenol (DMP) as phenolic one. Sensitivities of around 4.8 μA mg(-1)L and 2.7 μA mg(-1)L were attained for ABTS and DMP respectively. An excellent stability of this laccase biosensor was observed for over 6 months.

Catalyst and solvent free low pressure RF plasma polymerization strategy was used to develop multilayer biodegradable PCL-co-PEG (poly (e-caprolactone)-poly (ethylene glycole) copolymer) coatings for the controlled delivery of anticancer drug to reduce the nephrotoxicity (toxic effects to kidney cells) and myelosuppression (decrease in red blood cells). The resulting PCL-co-PEG coatings were characterized by FTIR-ATR and XPS. Multilayer drug delivery device can be tailored in such a way to have controlled cell–surface interactions and barrier layer dependent release. Cisplatin loaded (118 μgm/cm 2 ) PCL-co-PEG coatings with optimized ratios of e-CL/DEGME monomer feed in the plasma reactor were prepared for controlled cell death applications. Methylene blue (MB) was used as a model for cisplatin to simulate the drug release kinetics and the nature of which was examined by using the Korsmeyer–Peppas model for polymer coatings. Barrier layer dependent release was investigated by varying the deposition time from 5 to 50 min. Ellipsometric measurements were performed to understand the influence of surface hydration over the different chemically functionalized coatings with the incubation time. Human ovarian carcinoma cells (NIH:OVCAR-3) were cultured in physiological conditions and were seeded in a microplate which was loaded with autoclave coated glass cover slips for different time durations. Cell viability assay was performed to analyze the cell death. The results show that by gradually increasing the barrier layer thickness with deposition time, the amount of MB release was decreased which was modeled by analyzing the MB release kinetics. Investigations of each layer for multilayer PCL-co-PEG coatings were demonstrated over the drug delivery applications in vitro .

For the first time, a fast and versatile technique, an atmospheric pressure plasma jet (APPJ), has been used to functionalise graphite carbon electrodes for biofuel cell applications. The bioelectrode was functionalized by an atmospheric pressure plasma jet (APPJ) system using air, oxygen (O2) and nitrogen (N2) plasmas applied for only a few seconds. XPS analysis showed that carboxylic groups were created on the carbon substrates using both air and O2 plasmas, while mainly carbonyl and amine/amide functionalities were generated using N2 plasmas. A purified laccase from Trametes versicolor was both adsorbed and covalently bound (NHS/EDC method) to the plasma modified carbon. Higher laccase activity was obtained for the covalently grafted laccase compared to the physically adsorbed one: 13.2 (± 2) 10− 3U of laccase on air treated graphite and two-fold less (5.3 (± 1.1) 10− 3U) were obtained on N2 plasma treated surfaces (1 mM ABTS as a substrate, 30 °C, pH = 3.0), one unit (U) being the quantity of ABTS (μmole) oxidized by laccase per minute. Dioxygen reduction was performed by direct electron transfer (DET). The highest current density, 108 μA/cm2 (at 0.2 V (vs. SCE), pH 4.2, room temperature), was recorded for covalently immobilized laccase on N2 plasma treated surfaces (geometric surface = 0.38 cm2). This could be explained by the fact that the highly conductive graphite structure was retained in the case of this surface treatment and could also suggest a preferential orientation of the T1 Cu center of the laccase toward the surface of the N2 plasma treated electrode.

International audience; Thin films of fluorocarbon were deposited on polyethersulfone membranes via argon plasma sputtering of a poly(tetrafluoroethylene) (PTFE) target in an RF magnetron plasma reactor. The obtained deposited ultrathin coatings had nanoscale roughnesses and high degrees of fluorination. The intensity of fluorine atom in plasma environment during fluorocarbon deposition was investigated. Depending on the deposition conditions comprising working gas pressure, applied RF power, and distance between the target and the substrate, polymeric films with different chemical compositions and/or morphologies were obtained. The morphologies of the films were analyzed by means of SEM, XPS, and AFM. The results suggested that the sputtered film deposited at a higher pressure and longer target–substrate distance and moderate RF power had a surface composition and chemical structure closer to those of the PTFE film. The treated hydrophobic PES membranes with water contact angles as high as 115° were applied for the first time in an air gap membrane distillation setup for removal of benzene as a volatile organic compound from water. The results showed that the plasma-treated membranes have a comparable or superior performance to that of commercial PTFE used in membrane distillation with similar permeate flux and separation factor after 20 h long term performance.

International audience; In this article, we developed transporting plasma sources that operate at atmospheric pressure. The effect of electrode configuration on plasma transporting was investigated. In order to increase the transporting plasma cross-section, we converted a plasma stream into four plasma channels by a cylindrical housing. Electron excitation and rotational temperatures were estimated using optical emission spectroscopy. Furthermore, the electrical and temporal characteristics of the plasma, discharge power and charge deposition on the target were investigated. The propagation characteristics of single and multi-channel transporting plasma were compared with the same cross-sectional area. Two configurations for multi-channels were designed for this purpose. Escherichia coli bacteria were exposed to the single and multi-channel transporting discharge for different time durations. After exposure, the results indicated that the inactivation zones were significantly increased by a multi-channel transporting plasma. Finally, E. coli inactivation by those plasma apparatuses was compared with that of several standard antimicrobial test discs such as Gentamicin, Tetracycline, Amoxicillin and Cefixime.

The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmospheric pressure rotating plasma jet (APPJ) and the surface modifications were studied to assess its hydrophilicity and adhesion to acrylic adhesive tape intended for medical applications. Furthermore, the extent of hydrophobic recovery under different storage conditions was studied. The surface treatment of PDMS with the APPJ under optimal conditions noticeably increased the oxygen content and most of the surface silicon species were fully oxidized. A brittle silica-like layer on the outermost surface was created showing changes in topography due to the formation of grooves and cracks. A huge improvement in T-peel and the shear adhesive strength of the APPJ-treated PDMS surface/acrylic tape joints was obtained. On the other hand, the hydrophilicity of the PDMS surface increased noticeably after the APPJ treatment, but 24 h after treatment almost 80% hydrophobicity was recovered and the adhesive strength was markedly reduced with time after the APPJ treatment. However, the application of an acrylic adhesive layer on the just-APPJ-treated PDMS surface retained the adhesive strength, limiting the extent of hydrophobic recovery. The STSM Grant by COST ACTION MP1101 ‘Biomedical Applications of Atmospheric Pressure Plasma Technology’ and financial support from the Innovaciones DisRas S L Company is gratefully acknowledged.

Plasma polymerized polyacrylic acid (PPAA) was deposited on a polymer substrate, namely polyethylene terephthalate (PET) mesh, for entrapment of silver nanoparticle (Ag-NP) in order to achieve antibacterial property to the material. Carboxylic groups of PPAA act as anchor as well as capping and stabilizing agents for Ag-NPs synthesized by chemical reduction method using NaBH4 as a reducing agent. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and water contact angle analysis were used to characterize the PPAA coatings. The Ag-NPs loaded polymer samples were characterized by UV–visible spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray, and XPS techniques. XPS analysis showed ∼1.0 at.% loading of Ag-NPs on to the PPAA-PET-mesh, which was composed of 79% zero-valent (Ag°) and 21% oxidized nano-Ag (Ag+). The plasma processed PET meshes samples were tested for antibacterial activity against two bacterial strains, namely Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). Qualitative and quantitative tests showed that silver containing PPAA-PET meshes exhibit excellent antibacterial property against the tested bacteria with percent reduction of bacterial concentration >99%, compared to the untreated PET mesh. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.

Polyacrylic acid thin films have been deposited by an original and fast technique to grow organic coatings: a pulsed-arc atmospheric pressure plasma jet. Liquid acrylic acid was introduced in the nitrogen plasma jet and OES was used to measure the fragmentation of the precursor. The films were characterized by XPS, FTIR and SEM analyses before and after soaking in water. The water stability was also investigated by weight loss measurement. A high retention of carboxylic moieties, i.e. functional groups of the monomer has been observed for coatings deposited under mild conditions for the jet (low frequency and high jet speed). These films have been used for cell adhesion using human ovarian carcinoma cells (NIH:OVCAR-3). Good results have been obtained depending on the plasma parameters, showing that atmospheric pressure plasma jet is a promising technique to grow organic thin films for biomedical applications.

Thin films of TiN were prepared via RF magnetron reactive sputtering at various deposition pressures. The characteristics of the plasmas were measured by optical emission spectroscopy to optimize the conditions for the deposition of TiN coatings. After deposition, the thin films were annealed in a closed furnace at several different temperatures, and revealed the formation of different phases of TiO2. The resulting TiN/TiO2 thin films showed drastic changes in their crystal structure, optical properties, and photoelectrochemical performance. By examining how the deposition pressure and postdeposition annealing conditions affected the TiN film structure and performance, samples were prepared to optimize visible light absorption and activity. A model for the oxidation process was proposed which described the structural change from TiN to TiO2 through optical, morphological, and crystalline characterization. This study has systematically shown the ability to tailor the optical, crystalline, and photoactive p...

Catalyst-free ring-opening polymerization (ROP) strategy was developed to overcome the disadvantage of incomplete and expensive removal of catalyst used during the multistep wet chemical processes. Nano-sized biocompatible and low molecular weight poly(ε-carolactone)-poly(ethylene glycol) (PCL-PEG) copolymer coatings were deposited via a single-step, low-pressure, pulsed-plasma polymerization process. Experiments were performed at different monomer feed ratio and effective plasma power. The coatings were analyzed by XPS, as well as MALDI ToF. Ellipsometric measurement showed deposition rates ranging from 1.3 to 3 nm/min, depending on the ratio of the PCL/PEG precursors introduced in the reactor. Our results have demonstrated that plasma copolymerized PCL-PEG coatings can be tailored in such a way to be cell adherent, convenient for biomedical implants such as artificial skin substrates, or cell repellent, which can be used as antibiofouling surfaces for urethral catheters, cardiac stents, and so on. The global objective of this study is to tailor the surface properties of PCL by copolymerizing it with PEG in the pulsed plasma environment to improve their applicability in tissue engineering and biomedical science.

The ammonia plasma process was used for generating reactive groups, particularly primary amine functions on the surface of polyethylene (PE) films, to immobilize the enzyme trypsin. The attachment of the enzyme was achieved by directly applying an aqueous solution of trypsin to the plasma-activated surface or by using glutaraldehyde as a chemical linker. In both cases, the utilization of sodium cyanoborohydride efficiently stabilized the immobilization. The surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) and enzymatic activity measurements. Active trypsin was successfully immobilized on the surface with a mean activity of 0.09 ± 0.02 U/cm(2). The study of the stability of the immobilized enzyme during repetitive assays showed that some activity could be maintained during several months. An original quantitative correlation between the immobilized enzyme activity and the XPS signal intensity of the S 2p electrons present in the sulfur-containing amino acid residues was evidenced.

Silicon oxide based (SiOxCyHz, noted SiOx) coatings are often used in surface engineering for microelectronics, corrosion resistance, barrier to gas permeation through polymeric materials, etc… SiOx coatings can be efficiently deposited by non-equilibrium atmospheric pressure plasma processes, such as DBD or plasma jets. In the present study, the design of experiment (DoE) methodology was used to investigate the influence of process parameters on the characteristics of organosilicon coatings deposited by a non-equilibrium atmospheric pressure plasma jet (APPJ) from hexamethyldisiloxane (HMDSO) and air mixtures. The results obtained were used to create an empirical model to predict the chemical composition of coatings. Among 11 process parameters, the 3 parameters which exhibited the strongest effect on the coating composition were the torch speed, the substrate to nozzle distance and the number of scans. Auger spectroscopy revealed that the carbon content of the thin films was as low as 6 ± 1.7% and AFM analysis showed that smooth coatings (Ra ∼ 2 nm) were obtained even at high dynamic growth rates (∼1 000 nm · m · min−1). A tentative macroscopic scaling law was also formulated to correlate our results with the available literature data.

The present study deals with the deposition of plasma polymerized acrylic acid (PPAA) coatings on the surface of polystyrene beads. XPS analysis showed that the COOH content of the unwashed surface decreased by increasing the power, whereas the resistance to washing was improved weakly. The results showed that the use of an argon pretreatment of PS beads before plasma deposition of AA leads to a strong adhesion between PPAA coating and the underlying PS, reinforcing its stability. The study of the influence of the plasma deposition time clearly showed that the COOH content increased with the plasma treatment time, due to a better coverage of the PS beads. However, the stability of such coatings decreased inversely with the plasma treatment time due to their delamination.

Environmentally benign-solvent free plasma process is employed to produce nanostructured PFDA-co-DEGDME amphiphilic coatings via plasma co-polymerisation of 1H,1H,2H,2H-perfluorodecyl acrylate (PFDA) and diethyleneglycol dimethyl ether (DEGDME) precursors in a low pressure-RF-inductively excited tubular plasma reactor using argon as a carrier gas. The plasma-polymerised coatings are characterised by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and contact angle measurements. PFDA-co-DEGDME coatings with varying chemical environments and morphologies are achieved by varying the plasma parameters such as, continuous wave (CW) and pulse modulated (PM) plasma mode, and plasma deposition time. Plasma polymerised PFDA-co-DEGDME coatings are found to exhibit a switching property in terms of wettability, i.e., from hydrophobic to hydrophilic and vice versa, in response to the contacting environment. Quartz crystal microbalance (QCM) is used to study the adhesion of two model proteins, namely, human serum albumin (HSA) and fibrinogen (FGN) in continuous flow conditions, which reveals the protein repellent, i.e., anti-biofouling characteristics of the PFDA-co-DEGDME amphiphilic coatings.

Low surface energy fluorocarbon polymer coatings were prepared via plasma enhanced chemical vapor deposition (PECVD) of 1H,1H,2H,2H-perfluorodecyl acrylate (PFDA) in a low pressure inductively excited RF plasma. The influence of plasma parameters, such as, deposition time, continuous wave (CW) and pulse modulated (PM) plasma mode, plasma power and plasma duty cycle (DC) on morphology and wettablity of the PFDA was investigated using field emission scanning electron microscopy (FESEM) and contact angle (CA) measurement techniques. The plasma mode, plasma power and pulse duty cycle played a pivotal role in tailoring the surface morphology, wettability and the surface energy of the PFDA coating. The water CA hysteresis values for PFDA coatings suggested the wetting characteristics of the coating satisfying Wenzel model of nanostructured solid-water wetted contact. A thin conformal PFDA coating transformed a super-hydrophilic Whatman filter paper into a super-hydrophobic and oleophobic surface, which has industrial applications for development of durable, stain resistance and liquid repellent papers. The antifouling property of PFDA coatings investigated by quartz crystal microbalance (QCM) exhibited the protein repellent behavior against three model proteins namely, ovalbumin (OVA), human serum albumin (HSA) and fibrinogen (FGN).

International audience; Polypropylene (PP) particles are used for various purposes, however, the good mechanical properties of PP are counterbalanced by a poor wettability. The wettability of PP particles was therefore improved by an atmospheric pressure blown‐arc air plasma jet treatment in a new designed homemade Wurster fluidized bed reactor (Wurster‐FBR). This reactor, was used to treat 200 g of particles per batch. The surface free energy of PP particles determined by the Zisman method showed an increase from 30.7 to 38.6 mN m−1 after 120 s of treatment. XPS results showed a 5% increase of the atomic concentration of oxygen on the surface of the treated particles. In order to describe the process, a 2D axisymmetric non‐isothermal k‐ϵ turbulent model was used to determine the velocity field, pressure, and temperature profile of the gas phase inside the reactor. Furthermore an Eulerian‐Eulerian multiphasic CFD model was added to determine the dynamics of the particles inside the reactor, and the results were compared with fast imaging, thermocouple, and anemometry measurements. These investigations are very important to monitor the homogeneity of the particle treatments, to determine the average effective treatment time for each particle and to avoid overheating of thermally sensitive PP.

International audience; A novel hydrophobic membrane was developed by means of plasma polymerization of the polyethersulfone (PES) membrane using ethylene as the precursor to obtain appropriate performance in the membrane distillation (MD). The effects of plasma treating parameters including duration time, gas pressure, and power on the surface properties of the treated membranes as well as their MD performances were discussed. The surface properties of the treated samples were evaluated in terms of the surface morphology, chemistry, porosity and pore size, roughness, hydrophobicity, and Liquid Entry Pressure (LEP). The treated hydrophobic PES membranes with water contact angles of as high as 115° were obtained at high pressures and moderate powers. Response surface methodology was applied for modeling and optimization of the Air Gap Membrane Distillation (AGMD) system to separate benzene as a volatile organic compound from water. The plasma treated membranes showed fluxes at least as high as those of the commercial polytetrafluoroethylene (PTFE) membranes.

The thin film deposition in DBDs fed with Ar/HMDSO/O2 mixtures was studied by comparing the FT-IR spectra of the deposits with the GC-MS analyses of the exhaust gas. Under the experimental conditions investigated, oxygen addition does not enhance the activation of the monomer while it highly influences the chemical composition and structure of the deposited coating as well as the quali-quantitative distribution of by-products in the exhaust. Without oxygen addition a coating with high monomer structure retention is obtained and the exhaust contains several by-products such as silanes, silanols, and linear and cyclic siloxanes. The dimethylsiloxane unit seems to be the most important building block of oligomers. Oxygen addition to the feed is responsible for an intense reduction of the organic character of the coating as well as for a steep decrease, below the quantification limit, of the concentration of all by-products except silanols. Some evidences induce to claim that the silanol groups contained in the deposits are formed through heterogeneous (plasma-surface) reactions.