Effect of fluorine addition on the biological performance of hydroxyapatite coatings on Ti by aerosol deposition.
ABSTRACT Dense and well-adherent fluoridated hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2-x )F( x ), FHA] coatings with various amounts of fluorine contents (x = 0, 0.5, 1.0, 1.5, and 2.0) were deposited on commercially available pure titanium by aerosol deposition using FHA powders in order to investigate the effect of fluorine content on the properties of the coatings. FHA powders with different compositions were synthesized by solid-state reactions of hydroxyapatite (HA) and fluorapatite (FA) powders at various ratios. X-ray diffraction and Fourier transform infrared spectroscopy results showed that fluoride ions were successfully incorporated into the HA lattice for both the FHA powders and the FHA coatings. Scanning electron microscopy analysis revealed dense microstructures and good substrate adhesion of the coatings with high adhesion strengths of more than 33.1 MPa. The dissolution behavior in a tris-buffered saline solution indicated that the dissolution rate of the FHA coatings decreased as a result of increasing the fluorine content in the coatings. In addition, in vitro cellular tests, including cell attachment, proliferation, and alkaline phosphatase activity of MC3T3-E1 preosteoblast cells grown on the coatings, demonstrated that an FHA coating with a moderate degree of F(-) substitution, x = 1.0, had a stronger stimulating effect on cell proliferation and differentiation. These results suggested that there exists an optimum fluorine content level in the FHA coatings for the best long-term stability and cellular responses.
- SourceAvailable from: Roman A. Surmenev[Show abstract] [Hide abstract]
ABSTRACT: A systematic analysis of results available from in vitro, in vivo, and clinical trials on the effects of biocompatible CaP coatings is presented. An overview of the most frequently used methods to prepare CaP-based coatings was conducted. Dense, homogeneous, highly adherent, and biocompatible CaP or hybrid organic/inorganic CaP coatings with tailored properties can be deposited. It has been demonstrated that CaP coatings have a significant effect on the bone regeneration process. In vitro experiments using different cells (e.g. SaOs2, hMSCs, and osteoblast-like cells) have revealed that CaP coatings enhance cellular adhesion, proliferation, and differentiation to promote bone regeneration. However, in vivo, the exact mechanism of osteogenesis in response to CaP coatings is unclear, indeed there are conflicting reports of the effectiveness of CaP coatings with results ranging from highly effective to no significant or even negative effects. This review will therefore highlight progress in CaP coatings for orthopaedic implants and discuss the future research and use of these devices. Currently, an exciting area of research is in bioactive hybrid composite CaP-based coatings containing both inorganic (CaP coating) and organic (collagen, BMPs, RGD etc.) components with the aim of promoting tissue ingrowth and vascularisation. Further investigations are necessary to reveal the relative influences of implant design, surgical procedure, and coating characteristics (thickness, structure, topography, porosity, wettability etc) on the long-term clinical effects of hybrid CaP coatings. In addition to commercially available plasma spraying, other effective routes for the fabrication of hybrid CaP coatings for clinical use still need to be determined and current progress is discussed.Acta biomaterialia 11/2013; · 5.09 Impact Factor