Browsing by Author "Braceras, I."
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Item Bone cell adhesion on ion implanted titanium alloys(2005-06-22) Braceras, I.; Onate, J.I.; Goikoetxea, L.; Viviente, J.L.; Alava, J.I.; de Maeztu, M.A.; Tecnalia Research & Innovation; Biomateriales; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe authors have previously reported than ion implantation can have a significant effect on osseointegration of an implant, specially when the latter is introduced in areas of poorer bone density. These results indicate that this process is particularly suited for implant devices introduced in elderly patients or in those regions that have a poor quality of bone. The aim of this work is directed to study osteoblast adhesion on Ti alloy surfaces with different ion implantation treatments, so osseoconductive properties of several surfaces can be assessed. Polished discs of Ti–6Al–4V and Ti CP GR1 titanium alloy have been prepared and ion implanted with different species and parameters (dose and energy). Afterwards, the samples have been sterilized by UV light, inoculated with 1.5×105 human bone cells and incubated during 4 h at 37 C and 5% CO2 atmosphere. Then, once fixed and rinsed, image analysis has been used to quantify the number of cells attached to the Ti discs. On a second round of tests, cell proliferation tests have been conducted during 24, 48, 144 and 192 h, respectively. Furthermore, surface analysis techniques (e.g. AFM) have been applied to learn about the qualitative behavior, i.e. morphology, of the attached cells. Cell attachment has shown to be highly sensitive to ion implantation parameters. Although some quantitative differences have been observed, the more significant differences were qualitative. AFM analysis has shown that the star-shaped bone cells attached spread more and occupied larger surfaces like in osseointegration prone surfaces, most probably due to extracellular matrix synthesized around them, while other surfaces showed mainly large and narrow shaped or round shaped bone cells often with great cellular nucleus in the middle of the cells and little extracellular matrix around. So, ion implanted surfaces that facilitate osseointegration have been identified, in terms of initial bone cell attachment quality, where although the number of attached cells were not necessarily always larger, they tended to occupy wider areas with healthier cells.Item Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings(2015) Demnati, Imane; Grossin, David; Marsan, Olivier; Bertrand, Ghislaine; Collonges, Gérard; Combes, Christèle; Parco, Maria; Braceras, I.; Alexis, Joel; Balcaen, Yannick; Rey, Christian; EXTREMAT; INGENIERÍA DE SUPERFICIESChlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities.Item Effects of ion implantation on nano-topographic properties(2007-08-05) Braceras, I.; Briz, N.; García, F.; Muñoz, R.; Viviente, J.L.; Onate, J.I.; INGENIERÍA DE SUPERFICIES; SG; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; Tecnalia Research & InnovationIt is well known that surface properties at nano-scale are determinant in a number of applications, such as sensors, biomedical and optical devices. Nevertheless, relations between surface treatment parameters and their effects on topography at the nano-scale, surface energy or light reflectivity are often poorly understood. In this study, a non fluorescent glass material (Knittel) was selected and subjected to ion implantation treatments with different parameters and species, including Ar, Ne, C, N, CO and NH2. The resulting surface topography at the nano-scale was studied by Atomic Force Microscopy (AFM) and the surface energy was evaluated with the contact angle method. Additionally, the modifications induced on optical properties, i.e. reflection, were evaluated with two different wavelength lasers. The results showed remarkable differences in surface nano-topographies and contact angles (from 15° to 70°) that were obtained. Furthermore, the effects of ion implantation parameters had also very significant consequences on background noise effects, of great importance for optical properties. It was found that the best implantation treatment corresponded to N2 + ions implanted to a dose of 3×1017 ions/cm2 at an energy of 30 keV. This treatment resulted in a adequate contact angle, producing a nano-textured surface with potential features for a good attachment and orientation of deposited bio-molecules, and a very low background fluorescence, hence allowing a high degree of scanning sensitivity, for application on DNA microarrays. The study has shown that ion implantation represents a powerful tool for modifying key properties on surfaces that play an important role in the response elicited on living tissue and bio-molecules, which is notoriously relevant for the application as bio-sensors.Item Electrical contact resistance and tribological behaviors of self-lubricated dielectric coating under different conditions(2020-03) Echeverrigaray, F.G.; de Mello, S.R.S.; Leidens, L.M.; Boeira, C.D.; Michels, A.F.; Braceras, I.; Figueroa, C.A.; INGENIERÍA DE SUPERFICIESIn this study, the electro-tribological performance of hydrogenated amorphous carbon coatings against bearing steel in different experimental conditions was continuously monitored by means of coefficient of friction (CoF) and electrical contact resistance (ECR). The influence of tribosystem variables such as humidity, velocity and lifetime on frictional and electrical response were also compared with specific wear energy calculation method. The main findings of both tribological and electrical behaviors include the dissipated energy and the micro-slip dielectric failures that can be linked to the properties of self-lubricating layers, which depend also on the working media. In this framework, the electro-tribological evaluation provides an electrical monitoring tool for coating premature wear detection in real time.Item Fabrication and Characterization of a Novel Bioactive Poly(ether-ether-ketone) Scaffold for Bone Tissue Engineering (Poster)(MARY ANN LIEBERT, INC, 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA, 2015-09) Olalde, Beatriz; Oyarbide, Joseba; Ayerdi, Ana; Azpiroz, Patxi; Fernandez, Ruben; Aizpurua, J.; Braceras, I.; Alvarez, Noelia; Briz, N.; Morin, F.O.It is widely accepted that the initial interactions between the cells and implant surface are crucial to clinical success. One of the promising alternative materials for tissue engineering is polyetheretherketone (PEEK) which has good chemical resistance and mechanical properties similar to those of human bones [1]. However, its hydrophobic and chemically inert surface limits local bone attachment [2]. Consequently, there have been efforts to enhance PEEK bone-implant integration by incorporating molecules (such as HA) or making it porous [3]. Regarding to the latest, this study aims to demonstrate a process that can greatly enhance the density and interconnectivity of a PEEK porous product (US2012323339) [4]. Moreover, a novel surface modification through wet-chemistry protocol has been developed for RGD and OGP (osteogenic growth peptide) grafting onto porous PEEK scaffolds (US2013172273) [5]. As a result, the production of porous structures manufactured by thermally induced phase separation technique (TIPS), in combination with particulate leaching method, offers the greatest potential to control pore size and porosity whilst achieving porosity higher than 80%. Besides, surface functionalization of porous PEEK scaffolds with RGD/OGP combination is shown to enhance osteoblast adhesion, proliferation and differentiation, according to the in vitro results. In conclusion, we have developed a convenient “click” chemistry procedure to modify PEEK surfaces with RGD and OGP10-14 molecules, while keeping the bulk properties of PEEK as well as its biocompatibility in terms of cytotoxicity. The improvement of the osteogenic activity of this novel material shows that can be appropriated for bone tissue engineering applications.Item Improved osseointegration in ion implantation-treated dental implants(2002-09) Braceras, I.; Alava, J.I.; Onate, J.I.; Brizuela, Marta; García-Luis, A.; Garagorri, N.; Viviente, J.L.; de Maeztu, M.A.; Oate, J. I.; INGENIERÍA DE SUPERFICIES; Tecnalia Research & Innovation; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSImplants for knee, hip and dental part replacement are becoming increasingly used in surgery. Unfortunately, their use is sometimes accompanied by failure due to infection, inflammation, integration problems with the surrounding tissues or bone, and implant failure due to mishandling. Surface treatment, such as ion implantation, has been identified as a good candidate to modify the surface properties of the implant to significantly improve its osseointegration. This work reports on the ion implantation of light ions in commercial Ti6Al4V dental implants and subsequent osseointegration tests. Various light ions were implanted (C, N, CO, Ne) with energy ranging from 45 to 100 keV and doses up to 5×10e17 ions/cm2. Both ion-implanted and control dental implants were inserted in the tibial plateau of adult rabbits, the epiphysis and diaphysis of the tibia for the evaluation of their degree of osseointegration. After 3 months the implants were extracted and several histological sections were prepared from whole bones for evaluation of their osseointegration in the tibia. In addition, the surface of the implant, and the interface between the bone and the implant were examined by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. Some ion implantation treatments did not significantly change the performance of the dental implants relative to the untreated implants, while tests showed that the ion implantation of CO remarkably improved the osseointegration properties, i.e. the percentage of bone and implant in contact.Item In vitro corrosion behaviour of surgical 316LVM stainless steel modified by Si+ ion implantation – An electrochemical impedance spectroscopy study(2016-08-15) Galván, J.C.; Larrea, M.T.; Braceras, I.; Multigner, M.; González-Carrasco, J.L.; INGENIERÍA DE SUPERFICIESThis work deals with the surface modification of 316LVM stainless steel by Si+ ion implantation and the in vitro study of its effect on the short-term corrosion behaviour and ion release. In order to achieve a high Si content close to the surface, the experimental set up was designed with different implantation doses, acceleration voltages and angles of incidence. Corrosion tests were carried out by Electrochemical Impedance Spectroscopy (EIS). A special feature of this paper is the evaluation of the EIS data obtained through a critical analysis of the existing equivalent electrical circuits, in order to establish adequate parameters and scientific criteria to propose a classification of the corrosion response of the investigated surfaces. It has been demonstrated that doses of Si+ ion implantation equal to 2.5 × 1016 ion/cm2 and an acceleration voltages of 50 keV enhanced the corrosion protection. In contrast, higher ion-implantation dose (1 × 1017 ion/cm2) and acceleration voltage (80 keV) produced worse results, probably due to the development of strain induced α’-martensite. The quantity of relevant ions (Cr, Fe, Mn, Mo, Ni and Si) released to the medium was determined by an optimized Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) method. It has been shown that a better corrosion resistance is accompanied by a reduction in the amount of ions released.Item Interaction of engineered surfaces with the living world: Ion implantation vs. osseointegration(2007-08-05) Braceras, I.; Alava, J. I.; Goikoetxea, L.; de Maeztu, M. A.; Onate, J. I.; Biomateriales; Tecnalia Research & InnovationThe reaction of living tissues to foreign materials is a highly complex process that currently is insufficiently understood. Nevertheless, if specific reactions are to be promoted, this understanding is highly valuable and thus a significant research effort is being devoted to this issue. Typically, when a biomaterial is inserted in living tissue, proteins and other bio-molecules will adsorb to the surface. As this protein layer will mediate the interaction of the biomaterial with the living world, the consequent reactions will be highly dependant on this very first stage. Furthermore, different materials, i.e. surfaces, typically elicit a very different tissue response. It is commonly admitted that the primary adsorption depends heavily on the surface chemistry, surface topography and surface physical characteristics. Interactions between surface micro-topography and living cells have been widely studied, but protein specific reactions versus nano-topography have been barely explored. Ion beam modification of surfaces, which affect these key properties, can therefore be (i) a powerful tool to advance in the understanding of these nanoscale phenomena and (ii) useful as an industrial treatment of high value-added medical devices. This work will explore the application of ion beam based surface treatments to cause specific reactions in hard tissue regeneration. A variety of in vitro and in vivo results are presented corresponding to ion implantation treatments promoting "osseointegration" or intimate binding between the biomaterial and the living tissue, without any soft tissue interlayer, and an overview of the mechanism behind is offered, i.e. among other behaviour of osteoblasts, signalling proteins as the integrins, nanotopographic parameters.Item Magnetron sputtering of Cr(Al)N coatings: Mechanical and tribological study: Mechanical and tribological study(2005-10-01) Brizuela, Marta; García-Luis, A.; Braceras, I.; Onate, J.I.; Sánchez-López, J.C.; Martínez-Martínez, D.; López-Cortés, C.; Fernández, A.; López-Cartes, C.; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; Tecnalia Research & InnovationCrN coatings produced by magnetron sputtering are routinely deposited on tools and components for machining and forming applications. This paper reports on the effect of additions of aluminium (<15 at.%) on the mechanical and tribological properties of CrN coatings. Aluminium has been incorporated into CrN by co-sputtering of chromium and aluminium in a mixture of argon and nitrogen. Mechanical properties have been evaluated by ultramicroindentation techniques and scratch testing, while tribological tests have been carried out against ball bearing steel and titanium alloy balls by the pin-on-disc method. The thermal stability and oxidation resistance of the coatings have also been examined. A significant increase in hardness, reaching values up to 35 GPa, has been achieved for the CrAlN coatings when compared to CrN coatings. The improvement in tribological properties has also been remarkable, with a decrease in friction coefficient against bearing steel and also a non-adhesive wear mechanism against titanium alloy balls. In addition, the CrAlN coatings exhibited higher thermal stability than pure CrN coatings.Item Molten aluminium attack on iron based alloys(2017-05-04) Carrera, E. A.; Ramírez-Ramírez, J. H.; Pérez-González, F. A.; González, J. A.; Crespo, I.; Braceras, I.; Martínez-de-la-Pera, I.; Larrañaga, A.; Garza-Montes-de-Oca, N. F.; Pérez-Unzueta, A. J.; Talamantes-Silva, J.; Cavazos, J. L.; Colás, R.; PROMETAL; INGENIERÍA DE SUPERFICIESLiquid aluminium alloys affect the moulds, by formation of intermetallic layers at their surface; such attack is enhanced by the flow of the molten metal on the surface of the tooling. Metal tooling are used to promote high heat transfer rates and increase the solidification rate to enhance mechanical properties in cast pieces, but the damage to their surface affects their quality and increases the production costs due to the need to repair them. This work presents the results of a series of studies conducted to evaluate the attack produced by molten aluminium on samples of iron based materials commonly used in the manufacture of dies and moulds. The studies were conducted in a machine that imposes a rotating movement to experimental specimens to simulate the flow of liquid metal. The damage observed in the samples was compared to that experienced by tooling in the melt shop.Item MoSx lubricant coatings produced by PVD technologies(2007-03-01) Onate, J.I.; Brizuela, Marta; Viviente, J.L.; García-Luis, A.; Braceras, I.; Gonzalez, D.; Garmendia, Iñaki; Tecnalia Research & Innovation; INGENIERÍA DE SUPERFICIES; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; TECNOLOGÍAS DE HIDRÓGENOAmong the different options for solid lubrication, MoS2 is probably the most attractive due to its extremely low friction levels. Recent developments in magnetron sputtering physical vapour deposition (PVD) technology have allowed the development of MoS2 composite thin films with more compact structures, low friction behaviour and enhanced wear resistance, reducing degradation by humidity. The present work provides an overview of recent developments in dry lubrication with MoS2 films deposited by modern sputtering PVD and how these MoS2 films alloyed with Ti or WC can outperform conventional unalloyed films not only under vacuum but also under atmospheric high humidity conditions. MoSx–WC composite films outperform MoSx–Ti films, showing endurance at 0·75 GPa as high as 1·2 million wear cycles, also significantly higher than the values obtained from unalloyed, conventional MoS2 thin solid films. The films also exhibit a steady state friction coefficient from 0·02 to 0·04. In addition, these films also show resistance to humid environment when tested under atmospheric conditions.Item Tribología de nuevas capas autolubricantes producidas mediante PVD(2005) Oñate, J. I.; Brizuela, M.; Garcĩa-Luis, A.; Braceras, I.; Pacheco, S.; Viviente, J. L.; Tecnalia Research & Innovation; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSLas capas de MoS2 depositadas mediante PVD tienen baja fricción en vacío pero se degradan con facilidad al aire, especialmente en presencia de humedad. Este trabajo describe el desarrollo de nuevas capas de MoS^ modificadas con WC. En ensayos de "bola sobre disco" a 0,75 GPa, las capas presentaron una fricción muy baja y estable (< 0,04) en vacío. Se obtuvo una durabilidad superior a 1 millón de ciclos, mostrando un desgaste de 1,3 X 10e-16 me3 /Nm, mejorado respecto a otras capas de MoS2. El coeficiente de fricción aumentó a 0,15 y la durabilidad disminuyó hasta 1 a 3 x 10e5 ciclos en aire hasta 70 % HR.El análisis superficial mostró ratios de S/Mo superiores a 1,2, con menos del 2 % de oxígeno, demostrando carácter lubricante.Item Tribological study of lubricious DLC biocompatible coatings(2002-12-01) Brizuela, M.; Garcia-Luis, A.; Viviente, J. L.; Braceras, I.; Oñate, J. I.; INGENIERÍA DE SUPERFICIES; TECNOLOGÍAS DE HIDRÓGENO; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOS; Tecnalia Research & InnovationDLC (diamond-like carbon) coatings have remarkable tribological properties due mainly to their good frictional behavior. These coatings can be applied in many industrial and biomedical applications, where sliding can generate wear and frictional forces on the components, such as orthopaedic metal implants. This work reports on the development and tribological characterization of functionally gradient titanium alloyed DLC coatings. A PVD-magnetron sputtering technique has been used as the deposition method. The aim of this work was to study the tribological performance of the DLC coating when metal to metal contact (cobalt chromium or titanium alloys) takes place under dry and lubricated test conditions. Prior work by the authors demonstrates that the DLC coating reduced considerably the wear of the ultra-high-molecular-weight polyethylene (UHMWPE). The DLC coating during mechanical testing exhibited a high elastic recovery (65%) compared to the values obtained from Co-Cr-Mo (15%) and Ti-6AI-4V (23%). The coating exhibited an excellent tribo-performance against the Ti-6AI-4V and Co-Cr-Mo alloys, especially under dry conditions presenting a friction value of 0.12 and almost negligible wear. This coating has passed biocompatibility tests for implant devices on tissue/bone contact according to international standards (ISO 10993).Item Wear reduction effect on ultra-high-molecular-weight polyethylene by application of hard coatings and ion implantation on cobalt chromium alloy, as measured in a knee wear simulation machine(2001-07) Onate, J.I.; Comin, M.; Braceras, I.; García-Luis, A.; Viviente, J.L.; Brizuela, Marta; Garagorri, N.; Peris, J.L.; Alava, J.I.; Oate, J. I.; Garcia, A.; Tecnalia Research & Innovation; INGENIERÍA DE SUPERFICIES; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe most important factor affecting performance and longevity of hip joint and knee implants is the wear rate of the ultra-high-molecular-weight polyethylene (UHMWPE) component. UHMWPE wear debris has been linked to complications including tissue inflammation, bone loss (osteolysis) and implant loosening. Reduction of debris has been addressed by investigating new polyethylene formulations, manufacturing and finishing processes, including surface treatments and coatings both on plastic and metallic components. There have been many studies on the effect of surface treatments and hard coatings on cobalt chromium and titanium alloys for prosthetic applications. However, most of them have used laboratory tribo-testers without much correlation to articulating movements in human joints. In this work, hard coatings (TiN and DLC) and surface treatments (nitrogen ion implantation) have been investigated as potential candidates to reduce wear of UHMWPE, when applied on the counter face cobalt chromium alloy. Also the effect of applying nitrogen ion implantation on the UHMWPE surface itself has been investigated. To evaluate wear performance a special knee wear simulator has been used with a combined rolling-sliding movement that corresponds to the most unfavourable situation in the knee. As testing materials, conventional coated and uncoated Co–Cr as well as Al2O3 femoral heads were used against UHMWPE plates to obtain comparative data. Testing was carried out at 50 MPa using distilled water at 37±2°C as a lubricant. Wear measurements on UHMWPE were made following ASTM F732 standard by weight loss measurements and also by laser profilometry. The results, up to 5 million wear cycles that represent approximately 3 years of implant life, clearly have demonstrated the beneficial effects of diamond-like carbon (DLC) and ion implantation (both on Co–Cr and UHMWPE) in reducing wear of UHMWPE. Similar values were also obtained for Al2O3 ceramic material. A wear reduction up to approximately five times was obtained by the former materials, in comparison with the uncoated control specimen. However, the ion plated TiN coating increased significantly wear on the UHMWPE. Transference of UHMWPE to the ball was very evident with the uncoated control and TiN coated Co–Cr, as observed by SEM, but with DLC and the ceramic material this occurred to a much lesser extent. Some micro-delamination at the worn surface of the UHMWPE was observed when wearing against uncoated Co–Cr, but was not clear in the rest options. Ion implantation and DLC can thus be two good candidate treatments to reduce wear of UHMWPE in cobalt chromium knee and hip joint implants in substitution of a more expensive ceramic material. This DLC has passed all biocompatible tests in accordance with FDA regulations and ISO 10993 standards for implantable devices. An example of a uniformly DLC coated femoral head and knee implant is shown.