title: Silicon-substituted hydroxyapatite thin films: effect of annealing temperature on coating stability and bioactivity.
abstract: The effect of annealing temperature on the physicochemical and biological characteristics of magnetron cosputtered silicon-substituted hydroxyapatite (SiHA) thin coatings was studied. Annealing is required to transform as-sputtered amorphous films into crystalline coatings. A nanocrystalline, single-phase apatite structure was achieved for coatings heated to 600 or 700 degrees C and, with increasing annealing temperature, the crystallite size increased. Small crystallites were found to be more soluble in the physiological environment but, at the same time, were able to induce early formation of a new apatite layer. A human osteoblast-like (HOB) cell model was used to evaluate the performance of these annealed SiHA coatings. HOB cells attached and grew well on coatings and, after 42 days in culture, a mineralization process was observed to be taking place, with evidence of calcium phosphate minerals throughout the extracellular matrix. Our findings indicated that an annealing temperature of 600 degrees C is sufficient to achieve crystalline SiHA coatings and exhibiting good chemical stability and bioactivity.
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, UK. est23@cam.ac.uk
authors.forename: E S
authors.initials: ES
authors.lastname: Thian
authors.forename: J
authors.initials: J
authors.lastname: Huang
authors.forename: S M
authors.initials: SM
authors.lastname: Best
authors.forename: Z H
authors.initials: ZH
authors.lastname: Barber
authors.forename: W
authors.initials: W
authors.lastname: Bonfield
mesh_terms: D018786:Bone Substitutes / Q000138:chemical synthesis / Q000737:chemistry; D002113:Calcification, Physiologic / Q000502:physiology*; D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis / Q000737:chemistry; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry; D005109:Extracellular Matrix / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008567:Membranes, Artificial; D010006:Osteoblasts / Q000502:physiology* / Q000648:ultrastructure; D012825:Silicon / Q000737:chemistry; D013997:Time Factors
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D017886:Durapatite; D012825:Silicon