title: Magnetron co-sputtered silicon-containing hydroxyapatite thin films--an in vitro study.
abstract: The use of silicon-substituted hydroxyapatite (Si-HA) as a biomaterial has been reported recently. In vivo testing has shown that Si-HA promotes early bonding of the bone/implant interface. In order to extend its usage to major load-bearing applications such as artificial hip replacement implants, it has been proposed that the material could be used in the form of a coating on implant surfaces. This paper reports a preliminary study of the biocompatibility of magnetron co-sputtered silicon-containing hydroxyapatite (Si-HA) coatings on a metallic substrate. Magnetron co-sputtered Si-HA films of thickness 600 nm with a Si content of approximately 0.8 wt% were produced on titanium substrates. X-ray diffraction analysis showed that the as-deposited Si-HA films were either amorphous or made up of very small crystals. The crystallinity of Si-HA films was increased after post-deposition heat treatment at 700 degrees C for 3 h, and the principal peaks were attributable to HA. The formation of nano-scale silicon-calcium phosphate precipitates was noted on the heat-treated films. In vitro cell culture has demonstrated that human osteoblast-like cells attached and grew well on all films, with the highest cell growth and signs of mineralisation observed on the heat-treated Si-HA films. In addition, many focal contacts were produced on the films and the cells had well-defined actin cytoskeletal organisation. This work shows that as-deposited and heat-treated Si-HA films have excellent bioactivity and are good candidates when rapid bone apposition is required. Furthermore, heat-treated Si-HA films have improved biostability compared to as-deposited films under physiological conditions.
authors.affiliation: Department of Materials Science and Metallurgy, Cambridge Centre for Medical Materials, 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: D000199:Actins / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D049109:Cell Proliferation; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003599:Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry; D022001:Focal Adhesions; D006358:Hot Temperature; D006801:Humans; D006882:Hydroxyapatites / Q000737:chemistry*; D066298:In Vitro Techniques; D007202:Indicators and Reagents / Q000494:pharmacology; D008422:Materials Testing; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000378:metabolism; D010078:Oxazines / Q000494:pharmacology; D012825:Silicon / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D016596:Vinculin / Q000737:chemistry; D014961:X-Ray Diffraction; D014966:Xanthenes / Q000494:pharmacology
chemical_list: D000199:Actins; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D006882:Hydroxyapatites; D007202:Indicators and Reagents; D010078:Oxazines; D014966:Xanthenes; D016596:Vinculin; C005843:resazurin; D017886:Durapatite; C020243:calcium phosphate; D012825:Silicon