Fig. 2
Impact of dynamic culture conditions on the osteogenic differentiation of 2D on-chip cultures of MC3T2-E1 cells. Osteogenic differentiation capacity (Alizarin red staining) of cells cultivated in the 2D microfluidic biochip system for 4 (A-C) and 10 days (D-F). Significant increased Ca2+ intake was observed in the cells cultivated in differentiation media in static (E, 284% ± 97, p = 0.0029) and dynamic (F, 1600% ± 217, p < 0.0001) conditions using image analysis. Cells cultivated under dynamic conditions also generated micromass formations (F-arrows). G-I Cell spreading analysis using fluorescence staining (blue: Hoechst 33,342; green: F-actin). Cultivation of the cells under dynamic conditions for 4 days led to dendrite formation (I; white arrows) and exhibited a significantly higher aspect ratio (length vs. width depicted in K). This ratio was established as 1.9 ± 0.5, p = 0.9355 for proliferating cells, 1.9 ± 0.5, p < 0.0001 for cells cultivated in differentiation media and 3.6 ± 1.5 p < 0.0001 for cells cultivated in dynamic conditions (K). Scale bars = 100 μm (brightfield images) and 20 μm (fluorescence images)