Quantitative reverse transcriptase polymerase chain reaction analysis on days 1, 8, 16, and 24 of (a) alkaline phosphatase and (b) bone morphogenetic protein-2. All groups are normalized to day 1 100 µm static. In ALP data note no relevant significant difference between groups. In BMP-2 data note statistically significant increases of expression levels in 250 µm and 500 µm bioreactor groups on days 8, 16, 24. The symbols (*, #) indicate statistical significance from all other groups within a timepoint (p < 0.05). The abbreviation ND refers to no gene detected within 40 cycles.