title: In vitro assessment of the biological response to nano-sized hydroxyapatite.
abstract: Nano-sized, rod-like hydroxyapatite (nHA) crystals were produced and shown to be phasepure by X-ray diffraction analysis, as no secondary phases were observed. The nHA suspension was electrosprayed onto glass substrates using a novel processing routine to maintain nanocrystals of hydroxyapatite. The biocompatibility of nHAwas determined using human monocyte-derived macrophages and human osteoblast-like (HOB) cell models. The release of lactate dehydrogenase (LDH) from human monocyte-derived macrophages was measured as an indicator of cytotoxicity. The release of the inflammatory cytokine, tumour necrosis factor alpha (TNF-alpha) from cells in the presence of nHA crystallites was used as a measure of the inflammatory response. Although there was some evidence of LDH release from human monocyte-derived macrophages when in contact with high concentrations of nHA crystals, there was no significant release of TNF-alpha. Moreover, nHA-sprayed substrates were able to support the attachment and the growth of HOB cells. These results indicate that nHA crystals may be suitable for intraosseous implantation and offers the potential to formulate enhanced composites for biomedical applications.
authors.affiliation: Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK. jh357@cam.ac.uk
authors.forename: J
authors.initials: J
authors.lastname: Huang
authors.forename: S M
authors.initials: SM
authors.lastname: Best
authors.forename: W
authors.initials: W
authors.lastname: Bonfield
authors.forename: R A
authors.initials: RA
authors.lastname: Brooks
authors.forename: N
authors.initials: N
authors.lastname: Rushton
authors.forename: S N
authors.initials: SN
authors.lastname: Jayasinghe
authors.forename: M J
authors.initials: MJ
authors.lastname: Edirisinghe
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D001672:Biocompatible Materials / Q000737:chemistry; D002448:Cell Adhesion; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D005549:Foreign-Body Reaction / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000276:immunology / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010006:Osteoblasts / Q000276:immunology / Q000378:metabolism* / Q000473:pathology*; D010316:Particle Size; D013499:Surface Properties; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D014409:Tumor Necrosis Factor-alpha; D007770:L-Lactate Dehydrogenase