Figure 1
From: Mechanical activities of self-beating cardiomyocyte aggregates under mechanical compression
The mechanical response of a single cardiac spheroid (CS) to increasing compression. (a) A CS was fabricated by assembling human induced pluripotent stem cell-derived cardiomyocytes and human cardiac fibroblasts in a U-bottom well via layer-by-layer cell coating of fibronectin and gelatin. (b) A transparent polystyrene dish in which a CS was immersed in a culture fluid at a controlled temperature of 37 °C by a heater was lifted upward at a predetermined constant speed Vz (= dz1/dt). At t = 0, the CS made contact with two horizontal surfaces: the dish surface and the glass plate surface, where the glass plate (diameter: 1.0 mm and thickness: 0.2 mm) was mounted at the tip of a flexible probe with vertical stiffness kz. The compression of the probe spring was measured under an optical microscope. (c) Temporal change in the vertical position of the lower surface, z1 (as the input into the system). (d) Temporal change in the vertical position of the upper surface, z2 (as the output from the system). The blue and red circles denote the local minimum (i.e., CS relaxation) and local maximum (i.e., CS contraction), respectively. Experimental conditions: D = 340 μm (Ncell ~ 8000), kz = 3.4 N/m, and Vz = 10 μm/s.
