Radio frequency plasma treatments on titanium for enhancement of bioactivity.

Item does not contain fulltextTitanium and its alloys, when treated in alkali solutions, are able to form calcium phosphate coatings on their surface after immersion in supersaturated solutions. In this study, the surfaces of titanium alloy discs were modified by an alkali treatment and a radio frequency (RF) plasma procedure (150 W and 13.56 MHz) in N(2), CO(2) or N(2)/O(2) (80/20%) atmospheres. After the alkali treatment, atomic force microscopy showed differences in the surface roughness of the samples. X-ray photoelectron microscopy indicated that the chemical composition of the surfaces changed after the different alkali and RF plasma treatments. The contact angles were also modified by approximately 5 degrees , making the original titanium surface more hydrophilic. Immersion in a supersaturated calcium phosphate solution was used to evaluate the bioactivity of the RF plasma-treated samples in vitro. Alkali-treated samples gave more homogeneous and thick coatings that those without alkali treatment. The use of RF plasma treatments enhanced the bioactivity of the samples, in particular for treatments performed in N(2) or N(2)/O(2) atmospheres. Energy-dispersive X-ray analysis indicated that coatings had Ca/P ratios between the values of octacalcium phosphate and hydroxyapatite. X-ray diffraction confirmed the presence of these two phases in most of the coatings. This study shows that an RF plasma treatment enhanced the bioactivity of titanium surfaces

Treatment of a severely bleeding patient without preexisting coagulopathy with activated recombinant Factor VII

Item does not contain fulltex

Rapid prototyped porous titanium coated with calcium phosphate as a scaffold for bone tissue engineering.

Item does not contain fulltextHigh strength porous scaffolds and mesenchymal stem cells are required for bone tissue engineering applications. Porous titanium scaffolds (TiS) with a regular array of interconnected pores of 1000 microm in diameter and a porosity of 50% were produced using a rapid prototyping technique. A calcium phosphate (CaP) coating was applied to these titanium (Ti) scaffolds with an electrodeposition method. Raman spectroscopy and energy dispersive X-ray analysis showed that the coating consisted of carbonated hydroxyapatite. Cross-sectioned observations by scanning electron microscopy indicated that the coating evenly covered the entire structure with a thickness of approximately 25 microm. The bonding strength of the coating to the substrate was evaluated to be around 25 MPa. Rat bone marrow cells (RBMC) were seeded and cultured on the Ti scaffolds with or without coating. The Alamar Blue assay provided a low initial cell attachment (40%) and cell numbers were similar on both the uncoated and coated Ti scaffolds after 3 days. The Ti scaffolds were subsequently implanted subcutaneously for 4 weeks in syngenic rats. Histology revealed the presence of a mineralized collagen tissue in contact with the implants, but no bone formation. This study demonstrated that porous Ti scaffolds with high strength and defined geometry may be evenly coated with CaP layers and cultured mesenchymal stem cells for bone tissue engineering