FIG. 6.

Neurite growth anisotropy in experiments with a combination of a relatively steep YIGSR-grafted collagen gradient, and shallow IKVAV-grafted collagen with a 5-mm cross-channel. Each point represents the average length of neurites extending up the gradient and down the gradient from a single network±standard error of the mean (SEM). For the control condition, the direction with longer average growth was plotted as the ordinate value. The dashed line represents perfectly symmetric growth. In no case was growth perfectly uniform, though in control conditions, the points fell close to the dashed line. In the combined gradient condition, neurite growth was substantially and consistently biased up the gradient of adhesion. The experiments were further quantified to determine the average relative growth bias (Table 2) and average total length (Fig. 7).