Fig 1.
Analyzing movies of contracting human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs): (a) Still image of a beating hiPSC-CM movie. As per the schematic, z-discs, which define the ends of an ≈ 2 μm sarcomere, are fluorescently labeled; (b) Movie still with a schematic illustration of deformation gradient Favg and tracked sarcomeres overlaid, sarcomere color corresponds to contraction level with red indicating the highest level of contraction; (c) Magnitudes of average principal stretches (λ1, λ2) computed from Favg with respect to the movie frame number; (d) Average normalized sarcomere length with respect to the movie frame number. We note that the definitions of Favg, λ1, and λ2 are introduced in this text.