Figure 2
From: Mechanical activities of self-beating cardiomyocyte aggregates under mechanical compression
The static properties of single cardiac spheroids (CSs). (a) The normal load, Fz = kzz2, is plotted against the indentation depth, δz = (z1–z2)/2, for the local minimum values of z2(t) (i.e., the blue circles in Fig. 1d). The red broken line is a fitting function with a slope of 1.5 based on Hertzian contact theory for the contact between a sphere and a plane, used to evaluate the elasticity of the tested CS (e.g., its effective elastic modulus is E = 5.2 kPa). (b) The critical indentation depth δz-cr at which the CS was collapsed by compressive loading is plotted against the CS diameter, D, and is used to evaluate the toughness of the tested CSs. The black broken line is a linear fitting function intersecting the horizontal axis at D = Dmin = 146 μm. The plotted data in (b) are for ten different CSs, the diameters of which are ranged from 219 to 355 μm.
