Cell growth and function on calcium phosphate reinforced chitosan scaffolds

Macroporous chitosan scaffolds reinforced by calcium phosphate powders such as hydroxyapatite (HA) or calcium phosphate invert glass were fabricated using a thermally induced phase separation technique. Human osteoblast-like MG63 cells were cultured on the composite scaffolds for up to 11 days, and the cell growth and function were analyzed. The cell growth is much faster on the chitosan/HA scaffolds incorporated with the glass (CHG) than on the chitosan/HA scaffold without the glass (CH). The total protein content of cells were quantified and increased over time on both composites (CH, CHG) but was significantly higher on CHG after 7 days of culture. The cells on CHG also expressed significantly higher amount of alkaline phosphatase at days 7 and 11 and osteocalcin at day 7 than those on CH. The results suggested that the addition of glass in chitosan/hydroxyapatite composite scaffolds might enhance the proliferation and osteoblastic phenotype expression of MG63 cells. However, the chitosan-matrix scaffolds did not show higher phenotype expression of MG63 cells, in comparison with the TCPS plate, probably due to the degradation of chitosan and release of acidic byproducts. Larger amount of soluble calcium phosphate invert glasses should be added into the scaffolds to prevent chitosan from fast degradation that may affect the differentiation of osteoblast cells.