Figure 3.

Pulling the same receptor at different flow rates to investigate the relationship between drag force and displacement. (A–C) Receptor trajectories during multiple flow cycles along with the encountered barriers (dashed colored lines). Fig. S4 illustrates how the barrier positions were determined. (Red) Beginning of a trajectory. Color gradually changes (to yellow) toward the end of the trajectory. (D–F) Corresponding displacements over time for a series of different flow rates acting on the same receptors. (Dashed line) Flow rate. (Arrows) Points where the receptor passes over a barrier. These points have been determined by careful examination of the trajectory and the recorded positions (see text). For the highest flow rate in panel D at t = 400 s, a departure of the nanoparticle is observed most probably due to dissociation of the toxin from its receptor. (Horizontal dotted red, blue, and green lines) Barrier positions. (Black horizontal dotted line) Initial receptor position. The receptor displacements are calculated from the difference in mean positions before and during flow after an equilibrium position is reached (red points in D) and are plotted versus the flow rates in panels G–I.