title: In vitro bioactivity and gene expression by cells cultured on titanium dioxide doped phosphate-based glasses.
abstract: In our previous study, glasses with 50 P(2)O(5)-(20-15) Na(2)O-30 CaO-(0-5 mol%) TiO(2) have been prepared by the conventional melt-quenching process. MG63 cell proliferation, gene expression, in vivo biocompatibility, and bioactivity of these glasses is the concern of this study. The results showed that addition of TiO(2) in small amounts up to 5 mol% enhanced the biocompatibility of these glasses. The cell metabolic activity was conspicuous, on 3 and 5 mol% TiO(2) compositions in particular, with no significant difference from Thermanox control over a period of 21 days. The findings from the gene expression study showed that, at day 1 and on 5 mol% TiO(2) glass, core binding protein factor alpha 1 (Cbfa1) and alkaline phosphatase (ALP) showed significantly lower transcription level; however, collagen type I alpha subunit I (COLIAI) and Osteonectin (Sparc) showed no significant differences compared to the control. At day 7, all these genes transcription levels were not significantly different form the control, but at day 14, they were significantly higher than the control. Moreover, there were no significant differences detected in these genes on both 3 and 5 mol% TiO(2) glasses up to 7 days. At day 14; however, 5 mol% TiO(2) glasses showed significantly higher level than 3 mol% TiO(2) composition. This was also correlated by the presence of new bone tissue at the bone-particles interface for 5 mol% TiO(2) composition after 5 weeks of implantation in rat calvarium. Regardless of this favourable cell response and gene up-regulation, these glasses showed no evidence of apatite layer formation after 14 days incubation in SBF.
authors.affiliation: Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK.
authors.forename: Ensanya Ali
authors.initials: EA
authors.lastname: Abou Neel
authors.forename: Toshihide
authors.initials: T
authors.lastname: Mizoguchi
authors.forename: Michio
authors.initials: M
authors.lastname: Ito
authors.forename: Malak
authors.initials: M
authors.lastname: Bitar
authors.forename: Vehid
authors.initials: V
authors.lastname: Salih
authors.forename: Jonathan Campbell
authors.initials: JC
authors.lastname: Knowles
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D001826:Body Fluids / Q000737:chemistry; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D000090602:Collagen Type I, alpha 1 Chain; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry*; D051381:Rats; D012886:Skull / Q000473:pathology; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D050659:Core Binding Factor Alpha 1 Subunit; D015676:Osteonectin; D010710:Phosphates; C009495:titanium dioxide; D014025:Titanium; D000469:Alkaline Phosphatase