title: Novel silicon-doped hydroxyapatite (Si-HA) for biomedical coatings: an in vitro study using acellular simulated body fluid.
abstract: Magnetron co-sputtering was used to produce silicon-doped hydroxyapatite (Si-HA) as coatings intended for potential applications such as orthopedic and dental implants. It was found that the crystallinity of the as-sputtered coatings increased after annealing, resulting in a nanocrystalline apatite structure. Subsequently, the bioactivity of the coatings was evaluated in an acellular simulated body fluid (SBF). Physicochemical evaluation demonstrated that a carbonate-containing apatite layer, which is essential for bonding at the bone/implant interface, was formed on the coating surfaces after immersion in SBF between 4 and 7 days. The annealed coatings exhibited enhanced bioactivity and chemical stability under physiological conditions, as compared with the as-sputtered coatings. It is proposed that the rate at which the carbonate-containing apatite layer forms is dependent on the scale factor of the structure. A nanocrystalline structure can provide a higher number of nucleation sites for the formation of apatite crystallites, leading to a more rapid precipitation of carbonate-containing apatite layer. This work shows that Si-HA coatings offer considerable potential for applications in hard tissue replacement, owing to their ability to form a carbonate-containing apatite layer rapidly.
authors.affiliation: Cambridge Centre for Medical Materials, Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom. 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: D001826:Body Fluids / Q000737:chemistry* / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012825:Silicon / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D020099:Coated Materials, Biocompatible; D017886:Durapatite; D012825:Silicon