DLC-type layers offer a good potential for application in medicine, due to their excellent tribological properties, chemical resistance, and bio-inert character. The presented study has verified the possibility of alloying DLC layers with titanium, with coatings containing three levels of titanium concentration prepared. Titanium was present on the surface mainly in the form of oxides. Its increasing concentration led to increased presence of titanium carbide as well. The behavior of the studied systems was stable during exposure in a physiological saline solution. Electrochemical impedance spectra practically did not change with time. Alloying, however, changed the electrochemical behavior of coated systems in a significant way: from inert surface mediating only exchange reactions of the environment in the case of unalloyed DLC layers to a response corresponding rather to a passive surface in the case of alloyed specimens. The effect of DLC layers alloying with titanium was tested by the interaction with a simulated body fluid, during which precipitation of a compound containing calcium and phosphorus--basic components of the bone apatite--occurred on all doped specimens, in contrast to pure DLC. The results of the specimens' surface colonization with cells test proved the positive effect of titanium in the case of specimens with a medium and highest content of this element.
- MeSH
- biokompatibilní potahované materiály chemie MeSH
- biomedicínské technologie MeSH
- elektrická impedance MeSH
- fosfor chemie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- povrchové vlastnosti MeSH
- slitiny chemie MeSH
- tělesné tekutiny chemie MeSH
- testování materiálů MeSH
- titan chemie MeSH
- uhlík chemie MeSH
- vápník chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Diamond-like carbon (DLC) thin films are frequently used for coating of implants. The problem of DLC layers lies in bad layer adhesion to metal implants. Chromium is used as a dopant for improvement of adhesion of DLC films. DLC and Cr-DLC layers were deposited on silicon, Ti6Al4V and CoCrMo substrates by a hybrid technology using combination of pulsed laser deposition (PLD) and magnetron sputtering. The topology of layers was studied using SEM, AFM and mechanical profilometer. Carbon and chromium content and concentration of trivalent and toxic hexavalent chromium bonds were determined by XPS and WDS. It follows from the scratch tests that Cr doping improved adhesion of DLC layers. Ethylene glycol, diiodomethane and deionized water were used to measure the contact angles. The surface free energy (SFE) was calculated. The antibacterial properties were studied using Pseudomonas aeruginosa and Staphylococcus aureus bacteria. The influence of SFE, hydrophobicity and surface roughness on antibacterial ability of doped layers is discussed.
Titanium dioxide (TiO2) and Ag-incorporated diamond-like carbon (DLC) films were prepared on different substrates. The films were prepared by pulsed laser deposition (PLD). TiO2 and Ag were selected due to their potential values as biomaterials. Silver is effective against a wide range of spectrum including Gram-negative and Gram-positive bacteria and yeast. TiO2 and Ag-incorporated DLC thin films are suitable candidates for application on biomedical devices and implants due to their biocompatibility, chemical inertness, and mechanical properties. Thin films are widely used in coronary artery stents, dental implants, heart valves and other vascular devices. The microstructure and antibacterial properties of TiO2 and silver-doped diamond-like carbon (DLC) films have been investigated. The films structural quality was evaluated using SEM microscopy, AFM microscopy and Raman spectroscopy. The antibacterial activity was determined using Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. Our results demonstrate that the TiO2, nitrogen doped titanium oxides TON and Ag-incorporated DLC films are potentially useful as biomedical materials having good antibacterial properties.
Diamond like carbon (DLC) is applied as a thin film onto substrates to obtain desired surface properties such as increased hardness and corrosion resistance, and decreased friction and wear rate. Microdimple is an advanced surface modification technique enhancing the tribological performance. In this study, DLC coated microdimples were fabricated on hip prosthesis heads and their mechanical, material and surface properties were characterized. An Electro discharge machining (EDM) oriented microdrilling was utilized to fabricate a defined microdimple array (diameter of 300 µm, depth of 70 µm, and pitch of 900 µm) on stainless steel (SS) hip prosthesis heads. The dimpled surfaces were then coated by hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) layers by using a magnetron sputtering technology. A preliminary tribology test was conducted on these fabricated surfaces against a ceramic ball in simulated hip joint conditions. It was found that the fabricated dimples were perpendicular to the spherical surfaces and no cutting-tools wear debris was detected inside the individual dimples. The a-C:H and Ta-C coatings increased the hardness at both the dimple edges and the nondimpled region. The tribology test showed a significant reduction in friction coefficient for coated surfaces regardless of microdimple arrays: the lowest friction coefficient was found for the a-C:H samples (µ = 0.084), followed by Ta-C (µ = 0.119), as compared to the SS surface (µ = 0.248).
- MeSH
- biokompatibilní potahované materiály chemie MeSH
- kyčelní protézy * MeSH
- lidé MeSH
- povrchové vlastnosti MeSH
- uhlík chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Recently, diamondlike carbon (DLC) thin films have gained interest for biological applications, such as hip and dental prostheses or heart valves and coronary stents, thanks to their high strength and stability. However, the biocompatibility of the DLC is still questionable due to its low wettability and possible mechanical failure (delamination). In this work, DLC:N:O and DLC: SiOx thin films were comparatively investigated with respect to cell proliferation. Thin DLC films with an addition of N, O, and Si were prepared by plasma enhanced CVD from mixtures of methane, hydrogen, and hexamethyldisiloxane. The films were optically characterized by infrared spectroscopy and ellipsometry in UV-visible spectrum. The thickness and the optical properties were obtained from the ellipsometric measurements. Atomic composition of the films was determined by Rutherford backscattering spectroscopy combined with elastic recoil detection analysis and by x-ray photoelectron spectroscopy. The mechanical properties of the films were studied by depth sensing indentation technique. The number of cells that proliferate on the surface of the prepared DLC films and on control culture dishes were compared and correlated with the properties of as-deposited and aged films. The authors found that the level of cell proliferation on the coated dishes was high, comparable to the untreated (control) samples. The prepared DLC films were stable and no decrease of the biocompatibility was observed for the samples aged at ambient conditions.
- MeSH
- biokompatibilní materiály chemická syntéza chemie MeSH
- buněčné linie MeSH
- chemické jevy MeSH
- krevní plazma MeSH
- myoblasty fyziologie MeSH
- myši MeSH
- proliferace buněk * MeSH
- spektrální analýza MeSH
- testování materiálů * MeSH
- uhlík toxicita MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This study investigates a tribological performance of diamond like carbon (DLC) coated micro dimpled prosthesis heads against ceramic cups in a novel pendulum hip joint simulator. The simulator enables determining friction coefficient and viscous effects of a concave shaped specimen interface (conformal contact). Two types of DLC such as hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) and one set of micro dimple (diameter of 300µm, depth of 70µm, and pitch of 900µm) were fabricated on metallic prosthesis heads. The experiment results reveal a significant friction coefficient reduction to the 'dimpled a-C:H/ceramic' prosthesis compared to a 'Metal (CoCr)/ceramic' prosthesis because of their improved material and surface properties and viscous effect. The post-experiment surface analysis displays that the dimpled a-C:H yielded a minor change in the surface roughness, and generated a larger sizes of wear debris (40-200nm sized, equivalent diameter), a size which could be certainly stored in the dimple, thus likely to reducing their possible third body abrasive wear rate. Thus, dimpled a:C-H can be used as a 'metal on ceramic hip joint interface', whereas the simulator can be utilized as an advanced bio-tribometer.
Chromium-enriched diamond-like carbon (DLC) layers were prepared by a hybrid technology using a combination of pulsed laser deposition (PLD) and magnetron sputtering. XRD revealed no chromium peaks, indicating that the layers are mostly amorphous. Carbon (sp(2) and sp(3) bonds) and chromium bonds were determined by XPS from C 1s, O 1s, and Cr 2p photoelectron peaks. Depending on the deposition conditions, the concentration of Cr in DLC layers moved from zero to 10 at.% for as-received sample surfaces, and to about 31 at.% after mild sputter-cleaning by argon ion cluster beam. It should be noted that the most stable Cr(3+) bonding state is in Cr2O3 and Cr(OH)3, and that there is the toxic Cr(6+) state in CrO3. The surface content of hexavalent chromium in the Cr 2p3/2 spectra is rather low, but discernible. The population density of Saos-2 cells was the highest in samples containing higher concentrations of chromium 7.7 and 10 at.%. This means that higher concentrations of chromium supported the cell adhesion and proliferation. In addition, as revealed by a LIVE/DEAD viability/cytotoxicity kit, the cells on all Cr-containing samples maintained high viability (96 to 99%) on days 1 and 3 after seeding. However, this seemingly positive cell behavior could be associated with the risk of dedifferentiation and oncogenic transformation of cells.
- MeSH
- biokompatibilní materiály chemie toxicita MeSH
- chrom chemie MeSH
- diamant chemie MeSH
- lasery MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Silver doped diamond-like carbon layers were deposited by dual pulsed laser deposition using two KrF excimer lasers. The concentration of Ag, determined by XPS and WDS, moved from zero to ~10at%. We found that the sp2/sp3ratio, film roughness and the number of droplets (SEM and AFM) increased with increasing silver concentration. The sp3content measurement (XPS) was influenced by ion cluster surface sputtering and varied from 71.0% (undoped DLC) to 36.2% (for 9.3at% Ag). Transmission was measured on the scale from 200nm to 1100nm, and decreased with increasing silver content. An increase of Ag content has an effect on the decrease of the storage modulus (E') and the indentation hardness (HIT). The highest values HIT=51.9GPa and E'=270.6GPa were measured on a sample with 0at% Ag. The lowest values HIT=26.0GPa and E'=180.2GPa were measured on a sample of 9.3at% Ag. Film adhesion was studied using the scratch test and was up to 20.8N for the highest Ag concentration. The contact angle (CA) measurements for water showed that the CA of Ag-DLC films was higher (78°-98°) that of DLC film (77°). The surface free energy of DLC and of Ag-DLC was about 40mJ·m-2. Antibacterial properties were studied using gram positive and gram negative bacteria. The antibacterial effects increased with the Ag concentration and were ~99.9% after 24h for the layers with the highest silver content (9.3at%). Our results demonstrate that the Ag-doped DLC films are potentially useful biomaterials having both good mechanical properties and antimicrobial characteristics. PRIME NOVELTY STATEMENT: Unique manufacturing technique dual pulsed laser deposition was applied on hydrogen-free diamond-like carbon doped by Ag including topological, physical and antibacterial characterization.
- MeSH
- antibakteriální látky chemie MeSH
- diamant MeSH
- povrchové vlastnosti MeSH
- pyridoxal analogy a deriváty MeSH
- stříbro MeSH
- uhlík MeSH
- Publikační typ
- časopisecké články MeSH
Diamond-like carbon (DLC) thin films are promising for use in coating orthopaedic, dental and cardiovascular implants. The problem of DLC layers lies in their weak layer adhesion to metal implants. Chromium is used as a dopant for improving the adhesion of DLC films. Cr-DLC layers were prepared by a hybrid technology, using a combination of pulsed laser deposition (PLD) from a graphite target and magnetron sputtering. Depending on the deposition conditions, the concentration of Cr in the DLC layers moved from zero to 10.0 at.%. The effect of DLC layers with 0.0, 0.9, 1.8, 7.3, 7.7 and 10.0 at.% Cr content on the adhesion and osteogenic differentiation of human osteoblast-like Saos-2 cells was assessed in vitro. The DLC samples that contained 7.7 and 10.0 at.% of Cr supported cell spreading on day 1 after seeding. On day three after seeding, the most apparent vinculin-containing focal adhesion plaques were also found on samples with higher concentrations of chromium. On the other hand, the expression of type I collagen and alkaline phosphatase at the mRNA and protein level was the highest on Cr-DLC samples with a lower concentration of Cr (0-1.8 at.%). We can conclude that higher concentrations of chromium supported cell adhesion; however DLC and DLC doped with a lower concentration of chromium supported osteogenic cell differentiation.
- MeSH
- alkalická fosfatasa metabolismus MeSH
- biokompatibilní potahované materiály MeSH
- buněčná adheze * MeSH
- buněčná diferenciace * MeSH
- buněčné linie MeSH
- chrom chemie MeSH
- diamant chemie MeSH
- fokální adheze MeSH
- kolagen typu I metabolismus MeSH
- kovy chemie MeSH
- lasery MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- osteoblasty cytologie MeSH
- osteogeneze MeSH
- povrchové vlastnosti MeSH
- stanovení celkové genové exprese MeSH
- talin chemie MeSH
- uhlík chemie MeSH
- vinkulin metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
