Fig. 2

Sarcomere formation is accelerated in C2C12 myotubes grown on micropatterned gelatin hydrogels. Representative images of C2C12 myotubes 7 days post-differentiation grown on a collagen-coated glass coverslips, b unpatterned gelatin hydrogels, and c, e patterned gelatin hydrogels, as well as d and f. primary myotubes grown on patterned gelatin hydrogels. Myotubes are labeled with GFP-sarcomeric-α-actinin (green) and DAPI (blue). Images were analyzed by measuring sarcomere formation as defined by greater than 15 sarcomeres in series. g C2C12 myotubes and primary myotubes develop a greater number of sarcomeres in series when grown on micropatterned gelatin than on either unpatterned gelatin or collagen-coated glass. f Sarcomere length is stable by day 4 post-differentiation in micropatterned C2C12 and primary myotubes but continues to change in both collagen-coated glass and unpatterned gelatin conditions. f Images were visually assessed for the approximate number of sarcomere forming myotubes. C2C12 myotubes grown on micropatterned gelatin hydrogels develop sarcomeres more often, even when there are not enough sarcomeres in series to be included in other measurements. Primary myotubes grown on micropatterned gelatin hydrogels develop significantly more sarcomeres than all other conditions. *P < 0.05. **P < 0.01. ***P < 0.001