FIG. 3.
Effect of microgel diameter on MSC's proliferation and differentiation. The NRGD was kept constant at 6.22×108 NRGD/cm2. (A) The dependency of cell number (N) on cell culture period became larger with decreasing microgel diameter. The N was normalized to the number of cells adhered to the microgels within first 24 h of cell culture (No). The average diameter of the microgels were varied from 500 (▲) to 1500 (●) and 3000 μm (■). (B) Increasing the diameter of the alginate microgel significantly decreased the proliferation rate (k) (■), whereas it increased N0 (●). The difference between values was statistically significant (*p<0.05). (C) The degree of osteogenic differentiation of MSCs evaluated with measurements of the osteocalcin (C-1) and osteopontin (C-2) secretion levels after 7 days in culture showed no significant dependence on the microgel diameter. (D) The osteogenic differentiation of MSCs displayed by von Kossa staining was also independent of the diameter of the microgel and the cells were counterstained, shown in red. (D-1), (D-2), and (D-3) represent the microgel surfaces with diameter of 0.5, 1.5, and 3 mm, respectively (scale bar: 100 μm). Color images available online at www.liebertonline.com/tea