Fig. 6.

Analysis and quantification of cellular alignment with their underlying fibronectin patterns. A Sobel filter was used to assign an average orientation for 36 sub-regions for each pattern type based on the orientation of the actin fibrils within the cells or the fibronectin lines. These orientations are indicated by white lines on the patterned cell and fibronectin images. Within each sub-region the orientation from the cell image was then laid on top of the orientation from the fibronectin image into a merged image showing that the actin orientation within the cells qualitatively follows the direction of the underlying fibronectin patterns, which are based on the orientation of their underlying vector fields. To quantitatively prove this, the orientation of each cell sub-region was plotted against that of the fibronectin patterns (top graph), the difference between them was plotted (bottom graph), and a t-test was used to show that the averages of these differences in orientation were not statistically significant for any of the anisotropic patterns (n.s. = not significant).