Characterisation of calcium phosphate/titanium dioxide hybrid coatings.
The role of titanium dioxide (TiO2) as a means to engender enhanced stability into calcium phosphate (Ca-P) coatings has been well recognised. Several different methods have been used to create such Ca-P/TiO2 hybrid layers on a range of substrates. This paper reports the properties of a Ca-P/TiO2 system created by the sputter deposition of hydroxyapatite onto a titanium surface and the subsequent thermal diffusion of TiO2 through the porous Ca-P layer. The role of temperature in determining the surface contribution from TiO2 has been determined. Coatings annealed up to 600 degrees C did not exhibit any hybrid nature in the uppermost surface, however the coatings annealed to 700 degrees C did show the presence of both HA and rutile TiO2. The surfaces annealed to 800 degrees C were predominantly rutile TiO2. It was also observed that the Ca/P ratio decreased with increasing annealing temperature and that the coating annealed to 700 degrees C had a value of 1.82 +/- 0.07, which was closest to stoichiometric HA. Furthermore, the coatings that were annealed to 700 degrees C displayed a Ca-P/TiO2 hybrid nature, specifically in their uppermost surface and supported the growth and proliferation of osteoblast-like cells more readily when compared to the HA coatings or the rutile TiO2 surfaces.
Boyd
A R
AR
Northern Ireland Bioengineering Centre/Nanotechnology and Advanced Materials Research Institute, University of Ulster at Jordanstown, Shore Road, Room 25A18, Newtownabbey, Co. Antrim, Northern Ireland, UK. ar.boyd@ulster.ac.uk
Burke
G A
GA
Duffy
H
H
Cairns
M L
ML
O'Hare
P
P
Meenan
B J
BJ
D002130:Calcium Phosphates / Q000737:chemistry*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013057:Spectrum Analysis; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C009495:titanium dioxide; C020243:calcium phosphate; D014025:Titanium