title: Cell response to hydroxyapatite surface topography modulated by sintering temperature.
abstract: Increased mesenchymal stem cell (MSC) activity on hydroxyapatite (HA) bone tissue engineering scaffolds will improve their viability in diffusion-based in vivo environments and is therefore highly desirable. This work focused on modulating the sintered HA surface topography with a view to increasing cell activity; this was achieved by varying the sintering temperature of the HA substrates. Cells were cultured on the substrates for periods of up to 19 days and displayed a huge variation in viability. MSC metabolic activity was measured using a resazurin sodium salt assay and revealed that surfaces sintered from 1250 to 1350°C significantly outperformed their lower temperature counterparts from day one (p ≤ 0.05). Surfaces sintered at 1300°C induced 57% more cell activity than the control at day 16. No significant activity was observed on surfaces sintered below 1200°C. It is suggested that this is due to the granular morphology produced at these temperatures providing insufficient contact area for cell attachment. In addition, we propose the average surface wavelength as a more quantitative surface descriptor than those readily found in the literature. The wavelengths of the substrates presented here were highly correlated with cell activity (R(2)  = 0.9019); with a wavelength of 2.675 µm on the 1300°C surface inducing the highest cell response.
authors.affiliation: Trinity Centre for Bioengineering, Trinity College, Dublin, Ireland.|Dept. Mechanical and Manufacturing Engineering, Trinity College, Dublin, Ireland.
authors.forename: Jacob
authors.initials: J
authors.lastname: Mealy
authors.affiliation: Trinity Centre for Bioengineering, Trinity College, Dublin, Ireland.|Dept. Mechanical and Manufacturing Engineering, Trinity College, Dublin, Ireland.
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Kelly
mesh_terms: D000818:Animals; D002470:Cell Survival; D017886:Durapatite / Q000494:pharmacology*; D021621:Imaging, Three-Dimensional; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D010078:Oxazines / Q000378:metabolism; D013499:Surface Properties; D034421:Sus scrofa; D013696:Temperature; D014961:X-Ray Diffraction; D014966:Xanthenes / Q000378:metabolism
chemical_list: D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D017886:Durapatite
keywords: cell response; hydroxyapatite; oro-maxillo-facial; surface topography; tissue engineering