Figure 2.

Contractile force measurements of a stiff substrate coculture sample as an example showing the experimental set up as follows. (A) Screenshots of calcium flux across CMs; (B) bright-field images of the CM-CMF boundary and averaged beating force amplitude of CMs (top) and CMFs (bottom; the dashed line shows the CM-CMF boundary, and the white arrows show the nanoindenter colloidal probe) (scale bars, 100 μm); the gray and red curves represent the individual and averaged beating force of the cells, respectively; (C) contractile force magnitudes of CMs on different substrates. Data are shown as mean, and the error bar represents the SD of the measured values (^∗ indicates a statistically significant difference with p < 0.05) (n = 5); (D) fluorescence intensity representing the changes in Ca²⁺ transient in a single beat of CMs seeded on soft, moderate, and stiff substrates. To see this figure in color, go online.