Model for myotube alignment on patterned substrates. (*a*) Two identical square pyramidal wedges flanking a nucleus represent a model of myoblast. The extremities of the wedges are set to a thickness of 1 *μ*m. Values are justified in . (*b*) Determination of the maximum contact area as a function of the angle relative to the horizontal axis of symmetry for a single myoblast. The ventral footprint (in contact with a flat substrate) occupies an area of 400 *μ*m^{2}. As a single myotube is rotated around its center, the contact area increases until a maximum contact area is reached at an angle of ∼25° for the 20 *μ*m edge length square post-patterned substrates (*g* = 20 *μ*m separation; *squares*). As the separation increases to 30 *μ*m (*circles*) and 40 *μ*m (*triangles*), the maximum contact area occurs at smaller angles. The model predicts a maximum contact area for the 30 *μ*m and 40 *μ*m separation, but no alignment is observed experimentally. (*c*) Predicted values for angle of maximum contact area for the three lattices in *b*. The 20 *μ*m, 30 *μ*m, and 40 *μ*m separation square post lattices are represented by squares, triangles, and circles, respectively. The error bars in *c* correspond to the experimental values (± SD) measured for myotubes grown on these lattices.

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