The influence of a 3D macroporous scaffold (Sponceram) on the differentiation process into bone cells was investigated under static conditions in cell culture dishes. Furthermore, cultivations were performed using a new bioreactor system in the presence or absence of bone morphogenetic protein 2 (BMP-2). Preosteoblastic MC3T3-E1 cells were first cultured on Sponceram scaffolds in 96-well dishes using standard medium, differentiation medium and BMP-2 medium. Cell proliferation showed a similar course for all conditions used. Alkaline phosphatase (AP) activity resulted in a maximum at day 5 in the presence of BMP-2. Two bioreactor cultivations were performed in a BIOSTAT Bplus RBS (rotating bed system) 500 on Sponceram carrier discs. One cultivation was performed using standard medium. The second one was used with the same medium with BMP-2 substituted. Significant calcification of the extracellular matrix in the presence of BMP-2 occurred but even in the absence of BMP-2 mineralization was observed. mRNA expression of collagen I, osteocalcin and bone sialoprotein was detected after both reactor cultivations. This study demonstrates that macroporous Sponceram is suitable for the cultivation and differentiation of MC3T3-E1 cells into the osteoblastic phenotype. The results of the bioreactor cultivation revealed that the scaffold promoted the differentiation process even in the absence of BMP-2.
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