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: Willi Jahnen-Dechent[show abstract] [hide abstract]
ABSTRACT: The porous TiO2/perlite composite Ecopore is a synthetic biomaterial with possible clinical application in bone substitution. In our previous work, we demonstrated that surface modification of Ecopore with fibronectin (FN) enhanced spreading and growth of human osteoblasts in vitro. In the present study, we implanted untreated, alkaline-etched and FN-coated Ecopore cylinders into critical size defects of rabbit femora and applied pulsed polychrome sequence staining. After 6 weeks, sections of the implants were investigated via conventional and fluorescence microscopy. A partial ingrowth of bone matrix into the pore system of the Ecopore implants was observed. At the contact zones, the bone appeared to be directly connected to the implant without detectable gaps. Defect healing was complete within 6 weeks, while fibrous tissue generation or inflammation were absent in the implant modification groups, demonstrating basic Ecopore biocompatibility. The mean bone apposition rates within the implant cross-section were 4.1+/-0.6 microm/day (p<0.001) in the FN-coated group and 3.3+/-0.5 microm/day (p<0.05) in the NaOH-etched group. In both treated Ecopore modification groups, the apposition rates were significantly higher than in the non-modified control (2.9+/-0.6 microm/day), indicating bone growth stimulation by pre-treatment. Energy-dispersive X-ray analysis confirmed that significantly more bone tissue was formed inside the pores of the FN-coated implants compared to the unmodified control. The cross-sectional areas identified as ingrown bone amounted to 18.5+/-6.1% (p<0.05) in the FN group, 13.4+/-5.1% (p>0.05) in the NaOH-etched group and 10.2+/-5.5% in the unmodified group. In summary, we conclude that bone tissue tolerates Ecopore well and that tissue ingrowth can be enhanced by etching and coating with FN.Biomaterials 04/2006; 27(8):1270-6. · 7.60 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Novel structures with functional gradation in composition and structure were successfully made in Ti-TiO(2) combination using laser engineered net shaping. The addition of fully dense, compositionally graded TiO(2) ceramic on porous Ti significantly increased the surface wettability and hardness. The graded structures with varying concentrations of TiO(2) on the top surface were found to be non-toxic and biocompatible. In addition, the higher wettability of surfaces with TiO(2) can enhance their ability to form chemisorbed lubricating films, which can potentially lower the friction coefficient against ultrahigh molecular weight polyethylene liner, thus reducing its wear rate. These unitized structures with open porosity on one side and hard, low friction surface on the other side can eliminate the need for multiple parts with different compositions for load-bearing implants such as total hip prostheses.Acta biomaterialia 02/2009; 5(5):1831-7. · 3.98 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The surface of a titanium (Ti) implant was modified by micro-arc oxidation (MAO) treatment. A porous layer was formed on the Ti surface after the oxidation treatment. The phase and morphology of the oxide layer were dependent on the voltage applied during the oxidation treatment. With increasing voltage, the roughness and thickness of the film increased and the TiO(2) phase changed from anatase to rutile. During the MAO treatment, Ca and P ions were incorporated into the oxide layer. The in vitro cell responses of the specimen were also dependant on the oxidation conditions. With increasing voltage, the ALP activity increased, while the cell proliferation rate decreased. Preliminary in vivo tests of the MAO-treated specimens on rabbits showed a considerable improvement in their osseointegration capability as compared to the pure titanium implant.Biomaterials 07/2004; 25(14):2867-75. · 7.60 Impact Factor