Fig. 4: Cell traction force exerted on microposts with various surfaces.

Traction force development for MC3T3-E1 cell migration on PDMS microposts with a flat PDMS and b with nanopillar surfaces. c Normalized traction force in the leading, middle, and trailing regions of cells on microposts with various surface conditions. The tops of microposts were coated with FN and the sidewalls were coated with Pluronic. The yellow dashed line indicates the cell contour. The starting and ending positions are indicated by asterisks and dots in the micrographs, respectively. The white arrows indicate the traction force on the microposts. The length of the white arrow represents the magnitude of the traction force. Cell migration direction is marked by a blue arrow, representing the movement of the cell centroid during a single migration cycle. As the cell traction force varies from the leading to trailing region during migration, each cell is divided into three distinct isometric regions along its migration axis, including the leading, middle, and trailing regions. One-way ANOVA and Tukey’s post hoc test, ***p < 0.001.