Osteoblast response on silicon doped calcium phospate biomaterials.

摘要

Silicon stabilized alpha-TCP (Si-TCP) is the novel phase of Skelite(TM) bioceramics, a material used commercially as a bone substitute. Until now, the biological assessment of the Skelite(TM) bioceramics had primarily focused on osteoblast resorption, as this is an uncommon feature among bioceramics. This work constitutes the first thorough investigation of osteoblast response on Skelite(TM) and single phase Si-alpha-TCP pressed pellets, in vitro.; The effect of pressing pressure on the material properties and osteoblast response was examined first. No changes to the phase composition and chemistry were observed as the result of an increase in pressing pressure, only an increase of the bulk density and a decrease in surface microporosity. A positive correlation was observed between an increase in pressing pressure and the biological response of the osteoblasts. Increases in cell number, ALP production and mineralization were all observed with an increase in pressing pressure.; The effect of changing the bulk Ca/P ratio of Skelite(TM) pellets on material properties and osteoblast response was examined. Over the course of a 10 day osteoblast cell culture there were no observable trends in the osteoblast activity. It is believed that the benefit of an increase in Si-TCP and surface Si content with decreasing Ca/P ratio was countered by an increase in surface porosity.; To further explore the benefits of Si-TCP on osteoblast function, single phase Si-alpha-TCP was compared with Skelite(TM) (Ca/P = 1.66), single phase Si-HA and undoped HA. Si-alpha-TCP outperformed Skelite(TM) in terms of early stage metabolic activity, total mineralization (assessed by alizarin red staining) and net phase conversion to HA. Both Si-TCP based materials performed better than Si-HA in all cases, but they did not perform better than undoped HA. Osteoblast performance on HA pellets was on par with Skelite(TM) and Si-alpha-TCP but the HA pellets fall short on media reactivity. Tetracycline staining and XRD phase quantification revealed that the Si-TCP based pellets have a greater transformation than HA throughout the culture period.; The effects of proteins on media reactivity, nucleation and crystal morphology were also explored.