Fig. 2: The anisotropy of the optogenetically-induced contraction correlates with the microtissue architecture.

a Representative microtissue where the blue disc represents the 50 µm diameter isotropic stimulation area. b Resulting average displacement field (for readability reasons, only half of the vectors are represented) and c polar plot of its orientation. Data are presented as mean ± SD with n = 25 microtissues over 2 independent experiments superimposed with a dot plot of the data distribution. Resulting average strain fields (ε_xx in d, ε_yy in e) and comparison of the average strain amplitudes in the area of stimulation (f). Data are presented as Tukey box plots (i.e. the box extends from the 25th to 75th percentiles, the median is plotted as a line inside the box and the whiskers extend to the most extreme data point that is no more than 1.5 times the interquartile range from the edge of the box) with n = 25 microtissues over 2 independent experiments. ^****P < 0.0001 determined by a two-tailed t-test between ε_xx and ε_yy. g Confocal slice of the fluorescent staining of actin in a representative microtissue and h corresponding color-coded map of the actin orientation. i Polar plot showing the anisotropic orientation of actin fibers along the x-axis. j Confocal slice of the fluorescent staining of collagen in a representative microtissue and k corresponding color-coded map of the collagen orientation. l Polar plot showing the anisotropic orientation of collagen fibers along the x-axis. Data in (i) and (l) are presented as mean ± SD with n = 27 microtissues over 4 independent experiments superimposed with a dot plot of the data distribution. Scale bars are 100 µm. Source data are provided as a Source Data file.