Process for preparation of hydroxyapatite coatings
AssigneeBiocoatings S.r.l.
InventorsChristian Rey, Xavier Ranz
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Abstract
Coatings of scarcely crystalline carbonated hydroxyapatite are deposited on metallic or ceramic substrates, by immersing the substrates in a solution containing calcium phosphate and bicarbonate ions, with a molar ratio calcium/phosphate from 0.8 to 2 and a pH from 6.8 to 8.0. Subsequently, the solution is heated to 50-80° C., thus raising the pH and causing a spontaneous deposition of carbonated hydroxyapatite on the substrates. The obtained coatings are highly biocompatible, osteoconductive, bioactive and biodegradable, and can be utilized in structures used for preparing orthopaedic and dental prostheses and implants.
Claims13
A process for coating a substrate with a coating of a desired thickness consisting essentially of carbonated hydroxyapatite, which process comprises:
- (a) immersing the substrate to be coated in an aqueous solution containing calcium ions in a concentration of from 1 to less than 3.8 mmoles/liter, phosphate ions in a concentration of from 1 to less than 3.8 mmoles/liter and bicarbonate ions in a concentration of from 0.08 to 0.25 moles/liter, with a molar ratio calcium ions to phosphate ions from 0.8 to 2.0, a pH from 6.8 to 8.0 and a temperature lower than 50° C.:
- (b) heating at least the portion of the solution in contact with the substrate until the temperature reaches from 50 to 80° C. and the pH is greater than 8;
- (c) maintaining the substrate in contact with the heated supersaturated alkali solution obtained in step (b), thus causing formation of a carbonated hydroxyapatite coating to take place spontaneously directly at the contact with the surface of the substrate;
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- (d) removing the substrate from the solution, after the desired thickness of coating has been obtained, and subjecting the coating to drying.
Dependencies are inferred from the claim text.