Bone Abstracts

Biological calcification is a regulated process in which different types of tissues, cells and biomolecules participate in the coordination and regulation of the metabolic events involved in accumulating large amounts of calcium phosphate. This process could be speeded up using carbon nanotubes (CNTs) systems. The objective of our study was to compare cell growth and formation of mineralized matrix nodules by osteoblasts grown in plastic and in titanium (Ti) discs surfaces. The four sets of CNTs with diameter distribution size and disorder relatively large were prepared employing (Co, Mn) and (Fe) as catalysts, two sources of carbon precursors (methanol and ethanol) and NaCl substrate. Alkaline phosphatase activity and formation of mineral nodules were evaluated after addition of CNTs in different phases of cell growth. Better results for alkaline phosphatase activity and formation of mineral nodules were obtained when the cells were incubated with CNTs prepared with set (Fe, methanol) or (Co/Mn, ethanol) mainly in the presence of Ti surface. For alkaline phosphatase activity, CNT (Fe, methanol) showed 35% of increase in the intermediate phase of growth and 13% in the stationary phase, and CNT (Co/Mn, ethanol) showed 54% of increase in the intermediate phase and 26.7% in the stationary phase, when compared to the control. Observing the Ca/Pi molar ratios, the values closer to the hydroxyapatite ratio (1.666) were obtained for CNT (Fe, methanol) (1.95) and CNT (Co/Mn, ethanol) (1.64) in the presence of Ti surface, showing a great possibility of hydroxyapatite formation in these nodules. This study provides information for the application of different types of CNTs associated with Ti in processes of biomineralization stimulation, suggesting that depending on the CNT type there is an interaction between CNTs and Ti that favors the formation of mineral nodules on Ti surface.