Fig. 1. Nascent C2C12 skeletal myotubes on collagen patterns. (A) Patterns of collagen-coated rectangles, 20 µm wide and 200-1000 µm long, surrounded by interpenetrating polymer network (IPN). Even after 14 days of incubation with fluorescent collagen, the IPN shows no significant adsorption based on intensity. In addition, when measured by AFM, the apparent elastic modulus of the IPN is approximately half that of the collagen-coated glass. Scale bar, 200 µm. (B) Myoblasts plated onto the patterned coverslips were either stained for vinculin (and imaged by TIRF for clarity) or triple-stained for actin (red) myosin (green) and nuclei (blue). The cells invariably fuse to form multinucleated myotubes. The arrow points to the vinculin clustered at the edges of the patterned myotube, indicative of classical focal adhesion structures. The actin and myosin images show no striations and are of the same nascent myotube at day 6. Bars: in A 200 µm; in B 10 µm.