The morphology of MSCs seeded at (A-D) 10000 and (E-H) 50000 cells/cm2 within bgPS microchannels is shown for bgPS substrates that were previously subjected to (A, E) 0h, (B, F) 2h, (C, G) 4h, and (D, H) 16h of UV exposure prior to cell seeding. MSCs were stained for actin (green) and nuclei (blue). Scale bar is 500 microns.