Random migration in collagen gels.

aMeandering index is defined as net displacement divided by track length, such that migration in a straight line gives a value of 1, while greater meandering leads to values closer to zero. bAngle measures migration along the Y-axis. Values range from 0° to 180°, such that random migration should give a value of 90°. cBearing measures migration along the X-axis. Values range from 90°–270°, such that random migration should give a value of 180°.