title: An ultrastructural study of cellular response to variation in porosity in phase-pure hydroxyapatite.
abstract: Hydroxyapatite has been shown to be biocompatible and bioactive. Incorporation of porosity has been shown to enhance osteointegration; however, difficulty in controlling the extent and type of porosity has limited investigation into determining the role of both macro- and microporosity. The current investigation reports on the synthesis of four types of phase-pure hydroxyapatite with varying levels of porosity (HA1-HA4), and with defined levels of macro- and microporosities. Transmission electron microscopy was used to evaluate qualitatively the effect of these two parameters on cell-material interactions following a 30-day incubation period. Biological mineralization was observed within vesicles and the needle-like minerals were confirmed as hydroxyapatite using X-ray microanalysis. This demonstrated the suitability of primary human osteoblast-like cells as a tool to assess the extent of mineralization. Furthermore, internalization of hydroxyapatite particles was observed. Our findings show that the variation in macro- and microporosity does not affect the extent of cell-material interaction, with collagen synthesis evident in all samples.
authors.affiliation: IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London E1 4NS, UK. B.annaz@qmul.ac.uk
authors.forename: B
authors.initials: B
authors.lastname: Annaz
authors.forename: K A
authors.initials: KA
authors.lastname: Hing
authors.forename: M
authors.initials: M
authors.lastname: Kayser
authors.forename: T
authors.initials: T
authors.lastname: Buckland
authors.forename: L
authors.initials: L
authors.lastname: Di Silvio
mesh_terms: D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D006801:Humans; D046529:Microscopy, Electron, Transmission; D010006:Osteoblasts / Q000378:metabolism* / Q000648:ultrastructure*; D016062:Porosity
chemical_list: D017886:Durapatite