Micropatterned poly(dimethylsiloxane) substrates fabricated by soft lithography led to large-scale orientation of
myoblasts in culture, thereby controlling the orientation of the myotubes they formed. Fusion occurred on many chemically
identical surfaces in which varying structures were arranged in square or hexagonal lattices, but only a subset of patterned
surfaces yielded aligned myotubes. Remarkably, on some substrates, large populations of myotubes oriented at a reproducible
acute angle to the lattice of patterned features. A simple geometrical model predicts the angle and extent of orientation based on
maximizing the contact area between the myoblasts and patterned topographic surfaces. Micropatterned substrates also
provided short-range cues that influenced higher-order functions such as the localization of focal adhesions and accumulation
of postsynaptic acetylcholine receptors. Our results represent what we believe is a new approach for musculoskeletal tissue
engineering, and our model sheds light on mechanisms of myotube alignment in vivo.