The present work is focused on the micro-structural, antibacterial potential and corrosion resistance of silver (Ag) doped diamond-like carbon (DLC) coatings deposited by Thermionic Vacuum Arc on ...titanium substrates. The Ag-DLC coatings have spherical nanoparticulates in the film, with a size of either ≈50 nm or ≈20 nm, depending on the deposition time. The incorporation of Ag in the DLC coatings was clearly evident, as observed in both energy dispersive X-ray spectroscopy and in structural analysis (X-ray diffraction), while X-ray photoelectron spectroscopy confirmed their composition as well as the presence of Ag and diamond-like carbon. Such coatings show an increase in the wettability, which can be related to the increase in the surface free energy. Comparing their corrosion resistance to bare (uncoated) titanium, an increased electrochemical stability is observed. Subsequently, the silver release profiles in phosphate buffer saline, for a 10 days period, were investigated; the release is initially fast in the first 12 h followed by saturation at 66 h. These coatings were further investigated for antibacterial efficacy against Staphylococcus aureus (model Gram positive bacteria) which confirms that the silver doped DLC coatings exhibit an excellent antibacterial activity.
•Ag doped diamond-like carbon coatings were deposited by thermionic vacuum arc.•Characterization confirmed the structure of the Ag doped coatings.•Wettability was evaluated by contact angles and computation of the surface free energy.•Electrochemical tests for coatings and bare Ti were performed in Hank solution.•A range of corrosion resistance and antibacterial activity was established.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The aim of this study was to detect simultaneously four lung cancer biomarkers: CYFRA 21-1, CEA, NSE and HER-1, from blood samples. In order to do that, we have chosen stochastic senosors based on ...diamond paste matrices modified with different electroactive materials like dextrins and porphyrins, and ones based on three metals like Au, Cu and Ni. The stochastic sensors chosen for the screening tests of blood samples proved to be a good choice for the simultaneous detection of the four biomarkers, reaching low limits of determination of pg mL−1 magnitude order and high sensitivities. One main advantage of the sensors used for the simultaneous detection of the biomarkers is that the samples are analyzed as taken from the patients, without any pretreatment.
(1) Background: The high-voltage anodic-plasma (HVAP) coating technique has a series of specificities that are not simultaneously met in other deposition methods. This paper aimed at assessing the ...potential of HVAP to synthesize quality multilayers for X-ray optics. (2) Methods: Nanolayers of W, Ta, B, and Si were deposited as mono-, bi-, and multilayers onto very smooth glass substrates by HVAP, and their thickness and density were analyzed by X-ray reflectometry. The minimal film thickness needed to obtain continuous nanolayers was also investigated. (3) Results: Nanolayer roughness did not increase with layer thickness, and could be lowered via deposition rate, with values as low as 0.6 for the W nanolayer. Minimal film thickness for continuous films for the studied metals was 4 nm (W), 6 nm (Ta), 2.5 nm (B), and 6 nm (Si). (4) Conclusions: The investigation revealed the range of parameters to be used for obtaining quality nanolayers and multilayers by HVAP. Advantages and possible improvements are discussed. This deposition technique can be tailored for demanding applications such as X-ray mirrors.
The manuscript is focused on corrosion behavior of a Cr coating under CANada Deuterium Uranium(CANDU) primary circuit conditions. The Cr coating is obtained via the thermionic vacuum arc procedure on ...Zircaloy -4 cladding. The surface coating characterization was performed using metallographic analysis and scanning electron microscopy (SEM) with an energy dispersive spectra detector (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) investigations. The thickness of the Cr coating determined from SEM images is around 500 nm layers After the autoclaving period, the thickness of the samples increased in time slowly. The kinetic of oxidation established a logarithmic oxidation law. The corrosion tests for various autoclaving periods of time include electrochemical impedance spectroscopy (EIS) and potentiodynamic tests, permitting computing porosity and efficiency of protection. All surface investigations sustain electrochemical results and promote the Cr coating on Zircaloy-4 alloy autoclaved for 3024 h as the best corrosion resistance based on decrease in corrosion current density values simultaneously with the increase of the time spent in autoclave. A slow increase of Vickers micro hardness was observed as a function of the autoclaved period as well. The value reached for 3024 h being 219 Kgf/mm2 compared with 210 Kgf/mm2 value before autoclaving.
New nanostructured materials based on thin films of Cu and Ni deposited on textile material (veil), as well as gold nanostructured microspheres were used for the design of new stochastic sensors. The ...stochastic sensors were able to detect simultaneously a panel of biomarkers comprising epidermal growth factor receptor, neuron specific enolase, and carcinoembryonic antigen from whole blood samples with high reliabilities - recovery tests higher than 97.00%, with a RSD (%) lower than 0.1%. The stochastic sensors had shown high sensitivities and low determination levels for the detection of the proposed panel of biomarkers making early detection of lung cancer possible by fast screening of whole blood.
Nanostructured materials based on Cu and Ni and gold detect lung cancer at a very early stage.
The paper presents the investigation of a series of silver-incorporated diamond-like carbon (Ag-DLC) coatings with increasing Ag content on Ti50Zr and deposited using high voltage anodic plasma ...(HVAP). The coatings surface properties were analyzed with scanning electron microscope (SEM), atomic force microscope (AFM), and contact angle determinations. Electrochemical tests were performed in Afnor artificial saliva and evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. Based on these properties, comparisons of coatings performance were linked with the amount of deposited Ag. Increasing the Ag content led to the increase of the corrosion resistance and to the decrease of the forces exhibited on the surface. The hydrophobic character of the coating with the highest Ag amount could prevent thrombosis, thus suggesting its possible use for medical implants.
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