Improved osteoblast compatibility of medical-grade polyetheretherketone using arc ionplated rutile/anatase titanium dioxide films for spinal implants
ABSTRACT Titanium dioxide (TiO(2)), known to exhibit good biocompatibility, is applied in this study as a thin film formed onto polyetheretherketone (PEEK) substrate, which has been widely used in spinal interbody fusion cages. For successful deposition, an arc ionplating (AIP) technique was applied to deposit TiO(2) at low deposition temperature without damaging PEEK substrate, while providing satisfactory film adhesion. This study systematically investigates the effects of TiO(2) thin film phase composition and surface characteristics, controlled by using different target current and substrate bias, on osteoblast compatibility. Experimental results showed that anatase phase (A-TiO(2)) and/or rutile phase (R-TiO(2) ) TiO(2) coatings, respectively, can be prepared in appropriate deposition conditions. Overall, the TiO(2)-coated PEEK presented better osteoblast compatibility than the bare PEEK material in terms of cell adhesion, cell proliferation, and cell differentiation abilities, as well as osteogenesis performance (as determined by levels of osteopontin, osteocalcin, and calcium content). Surface roughness and hydrophilicity of the AIP-TiO(2) films were found to be responsible for significant osteoblast cell growth. It is also noticeable that the R-TiO(2) exhibited better osteoblast compatibility than the A-TiO(2) due to the presence of negatively charged hydroxyl groups on R-TiO(2) (110) surface in nature.
- SourceAvailable from: Paulo Emilio Correa Leite
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- "The interaction of hepatocytes and osteoblasts with rutile was already reported by some authors  . On rutile-rich films produced on β-Ti alloys by the micro-arc oxidation technique , an improved osteogenesis performance was observed  . The crystallographic lattice matching of rutile with that of apatite was referred as a possible mechanism for this behavior, resulting in an excellent apatite-forming ability of rutile surfaces  . "
ABSTRACT: Titanium (Ti) is commonly used in dental implant applications. Surface modification strategies are being followed in last years in order to build Ti oxide-based surfaces that can fulfill, simultaneously, the following requirements: induced cell attachment and adhesion, while providing a superior corrosion and tribocorrosion performance. In this work micro-arc oxidation (MAO) was used as a tool for the growth of a nanostructured bioactive titanium oxide layer aimed to enhance cell attachment and adhesion for dental implant applications. Characterization of the surfaces was performed, in terms of morphology, topography, chemical composition and crystalline structure. Primary human osteoblast adhesion on the developed surfaces was investigated in detail by electronic and atomic force microscopy as well as immunocytochemistry. Also an investigation on the early cytokine production was performed. Results show that a relatively thick hybrid and graded oxide layer was produced on the Ti surface, being constituted by a mixture of anatase, rutile and amorphous phases where calcium (Ca) and phosphorous (P) were incorporated. An outermost nanometric-thick amorphous oxide layer rich in Ca was present in the film. This amorphous layer, rich in Ca, improved fibroblast viability and metabolic activity as well as osteoblast adhesion. High-resolution techniques allowed to understand that osteoblasts adhered less in the crystalline-rich regions while they preferentially adhere and spread over in the Ca-rich amorphous oxide layer. Also, these surfaces induce higher amounts of IFN-γ cytokine secretion, which is known to regulate inflammatory responses, bone microarchitecture as well as cytoskeleton reorganization and cellular spreading. These surfaces are promising in the context of dental implants, since they might lead to faster osseointegration. Copyright © 2015 Elsevier B.V. All rights reserved.Materials Science and Engineering C 05/2015; 54. DOI:10.1016/j.msec.2015.05.012 · 3.09 Impact Factor
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ABSTRACT: Titanium (Ti) foams are attracting increasing interest in bone tissue engineering. The elastic modulus of Ti and its alloys can be reduced through the introduction of a porous structure, thereby addressing the stress shielding problem. Moreover, a porous structure may also provide new bone tissue ingrowth abilities and vascularization. In the present study, highly porous Ti scaffolds were prepared through a sponge replication method. The results showed that the Ti foam samples sintered in air at 800, 900, or 1000 °C exhibit the presence of rutile TiO2 on the Ti strut surfaces, which could bioactivate Ti foams. The oxide layers formed on the strut surface were relatively smooth and the thickness increased with an increase in sintering temperature. Additionally, the total porosities of the Ti foams sintered at three different sintering temperatures are larger than 79%, and open porosity is larger than 74%. The open porosity ratio is in excess of 0.92, suggesting that most pores are interconnected. Moreover, the strength and modulus of the sintered Ti foams conforms to the basic mechanical property requirement of cancellous bones. In this research, the highly porous Ti foams with a bioactive oxide layer were successfully fabricated by single-step sintering in air instead of a conventional vacuum atmosphere.Journal of Alloys and Compounds 10/2013; 575:326–332. DOI:10.1016/j.jallcom.2013.05.186 · 3.00 Impact Factor
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ABSTRACT: This paper relates to the in-flight temperature and velocity of TiO2 particles, an integral part of the systematic research on atmospheric plasma spraying of the material. Initial powder feedstock (32-45 μm, 100% rutile phase) was introduced into the plasma jet. Six parameters were selected to represent the versatility of the plasma system and their respective influences were determined according to basic one-at-a-time and advanced Taguchi design of experiments combined with the analysis of variance analytical tool. It was found that the measured temperatures varied from 2121 to 2830 K (33% variation), while the velocities of the particles were altered from 127 to 243 m/s (91% variation). Gun net power was detected as the most influential factor with respect to the velocity of the TiO2 particles (an increase of 8.4 m/s per 1-kW increase in net power). Spray distance was determined to have a major impact on the in-flight temperature (a decrease of 10 mm in spray distance corresponds to a drop of 36 K). A significant decrease in both characteristics was detected for an increasing amount of powder entering the plasma jet: A drop of 7.1 K and 1.4 m/s was recorded per every +1 g/min of TiO2 powder.Journal of Thermal Spray Technology 12/2013; 22(8):1320-1327. DOI:10.1007/s11666-013-9993-9 · 1.34 Impact Factor