Figure 4.

CPCs migrate toward lower oxygen concentration in an oxygen gradient device. (a) In a PDMS device (showed in the schematic representation) where 20% or 95% O₂ was applied at one end, and 1% O₂ at the other end, an increasing number of CPCs were observed at the lower oxygen side after 24 hours. Representative images show the increased amount of cells (nuclei stained with Hoechst 33342, blue). (b) The quantification of cell number (normalized to the initial value after seeding) is reported as mean ± SD (n = 4; ^∗P < 0.05; ^∗∗P < 0.01).