Fig. 3

Linking actuation effects on cell migration to focal adhesions. a, b Box plots showing cell motility parameters on 60/40 NIPAM/NEAM gels as a result of gel actuation, in comparison to non-actuating 0/100 NIPAM/NEAM control gels, a the migration rate b the persistence. The end-to-end distance, the contour length and the projected contour length can be found in Supplementary Fig. 12. c The Mean Squared Displacement as a function of lag times. (n = 2, N ≥ 43 cells). d–g Effect of actuation on the formation of focal adhesions is investigated using vinculin and paxillin immunofluorescence. d, e Cells are actuated for 12 h (340 mW, 1 Hz, 100 ms laser ON time), e shows a magnification of the dotted square in d. The edges of the ridge are marked by white dotted lines, showing an increase in focal adhesions along the ridge edges. f, g Control cells that are not irradiated with the laser and hence, not subject to actuation, with g showing a magnified image of the dotted square marked in f. h The total area occupied by all focal adhesions per cell. i The total number of focal adhesions per cell for the actuated and the non-actuated conditions are represented by box plots, which increase due to actuation. j Histogram of the area of focal adhesions for the actuated vs. the non-actuated cells (n = 3, N ≥ 17 cells). In the box plots, the interquartile range (IQR) between the first and the third quartiles is indicated by the box, while whiskers denote 1.5 IQR. The hollow square, the horizontal line, and the filled dots represent the average, the median, and the outliers, respectively. On the left of the box plot, all data points are shown, the normal distribution curve serves to guide the eye. *, **, *** are determined using one way ANOVA or Welch test, depending on the homogeneity of variances, and represent statistical significance at p < 0.05, 0.01 and 0.001, respectively. d–g Scale bar = 20 µm