title: Nucleation of biomimetic Ca-P coatings on ti6A14V from a SBF x 5 solution: influence of magnesium.
abstract: Biomimetic Calcium-Phosphate (Ca-P) coatings were applied by using 5 times concentrated Simulated Body Fluid (SBF x 5) using Carbon Dioxide gas. This process allows the deposition of a uniform Ca-P coating within 24 h. A previous study of our process emphasized the importance of hydrogenocarbonate ions (HCO-3), a crystal growth inhibitor. The aim of the present study was to investigate the role of the other crystal growth inhibitor present in SBF x 5, Magnesium (Mg2+), on the Ca-P coating formation. Several SBF x 5 solutions were prepared with various Mg2+ and HCO3 contents. No Ca-P deposits were detected on Ti6A14V substrate soaked for 24h in a Mg-free SBF x 5 solution, whereas by increasing HCO-3 content in a Mg-free SBF x 5 solution, a Ca-P coating developed on Ti6A14V substrate. Therefore, it appeared that Mg2+ has a stronger inhibitory effect on apatite crystal growth than HCO-3. Nevertheless, Mg2+ plays also another important role as suggested by depth profile X-ray Photoelectron Spectroscopy (XPS) of the Ca-P coating obtained from SBF x 5 solution. Ca2+ and Mg2+ contents increased significantly at the titanium/coating interface. Therefore, Ca2+ and Mg2+ initiated Ca-P coating from SBF x 5 solution. The relatively high interfacial concentration in Mg2+ favors heterogeneous nucleation of tiny Ca-P globules onto the substrate. So physical adhesion is enhanced at the early stage of the coating formation.
authors.affiliation: IsoTis BV, Bilthoven, Netherlands. florence.barrere@isotis.com
authors.forename: F
authors.initials: F
authors.lastname: Barrere
authors.forename: Blitterswijk C A
authors.initials: BC
authors.lastname: van
authors.forename: Groot K
authors.initials: GK
authors.lastname: de
authors.forename: P
authors.initials: P
authors.lastname: Layrolle
mesh_terms: D000497:Alloys; D001639:Bicarbonates / Q000737:chemistry; D001826:Body Fluids; D002130:Calcium Phosphates / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000494:pharmacology; D002254:Carbonates / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010949:Plasma / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001639:Bicarbonates; D002130:Calcium Phosphates; D002254:Carbonates; D007477:Ions; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C031462:titanium alloy (TiAl6V4); D002245:Carbon Dioxide; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D014025:Titanium; D008274:Magnesium; C485829:calcium phosphate, dibasic, anhydrous