Figure 3.

Contact guidance is related to cell speed, eccentricity, and the spatial patterning of protrusions and retractions along the cell boundary. (A) Distributions of velocity direction with respect to the nanoridge direction for cells moving on 1.2-μm-spaced nanoridges. Velocity direction is weighted by speed. The cells were ranked by speed and then binned. The red line represents the weighted velocity for the slowest sixth of cells, and the purple line the weighted velocity for the fastest sixth of cells. Faster cells are more likely to move parallel to the nanoridges than are slower cells. (B) Distributions of alignment, weighted by eccentricity, with respect to the nanoridge direction. The cells were ranked by eccentricity and then binned. The red line represents the alignment distribution for the most circular cells, and the purple line represents the distribution for the most elongated cells. More elongated cells are more likely to be aligned parallel to the nanoridges than are more circular cells. (C) Surface contact guidance efficiency as a function of cell eccentricity. One experiment is shown for each nanoridge spacing. (D) Protrusive and retractive motion as a function of arc length (x-axis) and alignment with respect to the nanoridges (color). For protrusions, shown as solid lines, the boundary position zero represents the front of the cell. For retractions, shown as dashed lines, the boundary position zero represents the back.