Fig. 2.

Density of the sarcomere network in iPSC CMs subjected to different culture conditions. A The mean sarcomere density of iPSC CMs was comparable to neonatal cells and significantly increased upon cultivation under optimized conditions (iPSC CM longCon, iPSC CM struCon). B A profound increased number of cells with high sarcomere density was detected after prolonged cultivation time (iPSC CM longCon). This effect was even more pronounced when cells were grown on structured surfaces (iPSC CM struCon). C Binary images of the α-actinin network indicate the difference in sarcomere density upon treated groups. Note that cell size was modified for better visualization of sarcomere filaments. Statistical analysis of sarcomere density was performed using one-way ANOVA, followed by Dunett’s post hoc test, n = 41–50, *p < 0.05, **p < 0.01, ***p < 0.001, ^#p < 0.001 compared to all groups