Fig. 2: Cells deposit a footprint on their tracks.

a Principle of the substrate conditioning. Linear tracks were micro-contact printed (1), then a first layer of cells was plated at high density to recover all the surface (2) before being detached (3). b Kymograph of a cell moving along a conditioned 20 μm track with high persistence. Scale bar (repeated vertical line) 100 μm. c Trajectories of cells on control (Ctl: substrate kept in PBS, Medium only: substrate kept in DMEM during the same time as the conditioning) or conditioned susbtrates as a functions of time. This shows high persistence on conditioned susbtrates. Only trajectories of at least 10 h duration are shown. d Trajectories of single cells plated on 2D surfaces on control (Ctl, blue) or conditioned (Cond., red) substrates. e Distance of the cell to its original position after 16 h on control and conditioned substrates in 1D and 2D. Differences were assessed using the 2-sample Kolmogorov–Smirnov test, n.s.: non-significant (p > 0.1), ***p < 0.001. Exact p-values are p = 0.89, 1.4e −29, 4.5e−26, 4.8e−27, 7.2e−24 comparing between MDCK 1D (Ctl-Med, Ctl-Cond., Med.-Cond.), Caco2 1D and MDCK 2D data, respectively. n = 355, 238, 429, 246, 216, 192, and 194 trajectories from 3 (MDCK 1D, Ctl/Medium/Cond.), 3 (Caco2 1D, Ctl/Cond.) and 2 (MDCK 2D, Ctl/Cond.) independent experiments respectively. f Phase-contrast image of a MDCK cell on a conditioned line on soft PDMS, overlaid with traction stress. Scale bar 20 μm. Typical force profile observed in 3 independent TFM experiments with single MDCK cells. g Traction force profile along the cell, integrated over the line width. h Tension T within the cell obtained by integrating the traction force profile along the x-axis. i Maximal (peak) tension of cells on control (blue) or conditioned (red) linear substrates. Difference between n = 26 and 31 cells was tested using the 2 sample Kolmogorov–Smirnov test, ***p = 1.6 × 10⁻⁴. j Fluorescence pictures of a line conditioned by MDCK cells, then fixed. ‘Pattern’ denotes the stamped labelled fibronectin, cellular fibronectin and laminin are immuno-stainings. k–l Cellular fibronectin (k) and laminin (l) staining intensity in control (blue) and conditioned (red) lines devoid of cells. Difference between n = 48 pictures (192 line patterns) from two independent experiments per condition was tested using the 2 sample Kolmogorov–Smirnov test, ***: p = 5e− 22 for both (k, l). The violin plots in panels e, i, k, l display the full distribution of data points together with a standard box plot.