Colloidal-sol gel derived biphasic FHA/SrHA coatings

Fluoridated hydroxyapatite/strontium-substituted hydroxyapatite (FHA/SrHA) biphasic coatings are prepared on titanium substrate via colloidal-sol gel method, where FHA acts as the dissolution-resistant matrix and SrHA serves as the soluble phase. Surface characterization, adhesion strength and solubility as well as in vitro cellular responses of FHA/SrHA biphasic coatings were investigated. FHA/SrHA biphasic coating displays unique surface characteristics in comparison with single phase coating. The dissolution rate of FHA/SrHA biphasic coatings is much slower than that of pure SrHA coating, which increases progressively with increasing amount of SrHA and is between that of pure FHA and SrHA coating. The adhesion strength between coating and Ti substrate decreases with increasing amount of SrHA. The cultured osteoblastic MG63 cells attached, spread, and grew favorably on the FHA/SrHA2 (molar ratio of FHA and SrHA is 1:2) biphasic coating film.