Fig. 1.

Typical behavior of THP1 cells larger than the microchannels: trajectories (red lines in A and B, Top) and X-position along the network versus time (A and B, Bottom). White dots circled in red (A and B, Top and Bottom) correspond to the cell positions when they are in the center of the horizontal channels. (A) A 15-$\mathrm{\mu }$m cell entering a 10.6-$\mathrm{\mu }$m channel network moves randomly between the pillars for the first eight meshes before alternating between two channel rows, $\mathrm{\Delta }P$ = 40 mbar. The transit time through a mesh is still irregular (with a long stop at the exit of the 13th horizontal channel) before steady state is reached at mesh 14 (shown by the yellow line). This cell, which stays longer in the transient regime than other cells, was chosen to highlight the initial random motion. (B) A 15-$\mathrm{\mu }$m cell flowing in steady state through the last 9-$\mathrm{\mu }$m-wide channels of a network, $\mathrm{\Delta }P$ = 20 mbar.