Effect of sinterezed beta-tricalcium-phosphate and titanium granulate on human osteoblasts

Objectives: The connection called osseointegration between the implantation and its' bone environment is critical. In our study we investigated the effect of the sinterezed beta-tricalcium-phosphate and titanium granulate on osteoblast cells. The aim of the study was to create new surfaces which contain B-TCP beside Ti and determine the most favourable ratio for the differentiation of osteoblasts and for the creation of extracellular matrix. Methods: Powders with different concentration of Beta-tricalcium-phosphate B-TCP (0-5-25%) were pressed with 30000N pressure onto disks with a diameter of 15mm and were sinterezed in vacuum chamber. The cell adhesion and morphology examination were performed with confocal laser scanning microscope (LSM 510, 40X/0.6 Na objective), osteogenetic gene-expression (osteocalcin) in human osteoblasts' DNA with real time polimeras chain reaction (TaqMan Gold RT-PCR Kit). As an endogenous control 18s riboszomal RNS (Applied Biosystems Kit 4310893E) was used. Results: Larger number of cells was harvested from control surfaces than from the modified disks. RT-PCR revealed that cell counts decreased when we increased the B-TCP content in the composite and the same tendency was resulted with RNS concentration. The morphology also showed differentiation because the shape of the cells was long, elongated compared to the control cells with less connecting surfaces to each other. Conclusion: The B-TCP facilitates bone configuration around implantation surfaces but higher amount of B-TCP is dramatically reducing the cell adhesion. The physical property of calcium phosphate crystals that inhibits cell proliferation may be surmounted by the inhibition of intracellular signalling pathway to rescue delayed proliferation of osteoblasts on this surface. Our future plan is to find the optimal composition for physical properties and surface morphology. The work/publication is supported by the TÁMOP 4.2.1/B-09/1/KONV-2010-0007 project. The project is co-financed by the European Union and the European Social Fund.