Figure 4.

Tracks of sperm interactions with solid structures, as seen looking down from above. (a) Sperm that approach a sidewall from all angles (starting points denoted with open dots) swim along the sidewall (end points denoted with filled black dots) after hitting the wall. The location of wall contact is adjusted to (0,0) for each trajectory. (b) When sperm encounter a microgroove structure, the overwhelming majority of them remain in the groove. The starting points of the tracks are adjusted to (0,0). End points of the sperm trajectories are indicated by black dots. Note that sperm swim in either direction from the point of entry into the microgroove. Only one out of 50 sperm swam out of the microgroove. Adapted from Ref. [53]. Copyright 2015 by the authors.