Pre-conditioning and dual constant composition dissolution kinetics of pulsed laser deposited hydroxyapatite thin films on silicon substrates

• Published in: Biomaterials Vol. 17; no. 6; pp. 631 - 637
• Main Authors: Tucker, B.E., Cottell, C.M., Auyeungt, R.C.Y., Spector, M., Nancollas, G.H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.03.1996; Elsevier Science
• Subjects: Biological and medical sciences; calcium phosphate; Calcium Phosphates - metabolism; dissolution; Hydrogen-Ion Concentration; Hydroxyapatite; Hydroxyapatites - chemistry; Hydroxyapatites - metabolism; Lasers; Medical sciences; prosthetics; pulsed laser deposition; Silicon - chemistry; Solubility; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Technology. Biomaterials. Equipments; Temperature; X-Ray Diffraction; Hydroxyapatite; calcium phosphate; pulsed laser deposition; prosthetics; dissolution; Biomaterial; Kinetics; Pulsed laser; Prosthesis
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/0142-9612(96)88714-X

The kinetics of dissolution of pulsed laser deposited crystalline and amorphous thin films of hydroxyapatite on silicon substrates were measured at 37 °C and a pH value of 6.5 using the dual constant composition method. Solutions in which the pulsed laser deposited films were preconditioned (0.15 m NaCl) remained undersaturated or slightly supersaturated with respect to hydroxyapatite after equilibrium was reached, indicating only a very small coating release and the absence of re-precipitation on the surfaces. The amorphous films released more calcium and phosphate during pre-conditioning than the more crystalline films. Dual constant composition dissolution rates decreased as film crystallinity increased. The film with the lowest dissolution rate (approximately one sixth that of a crystalline film deposited using a hydroxyapatite powder target) was fabricated using a human tooth as the laser target. During pre-conditioning of plasma-sprayed coatings, more calcium and phosphate were released than for pulsed laser deposited films, and dual constant composition dissolution rates were much higher.