AFM dwell map of dilated cardiomyopathy iPSC-CM.

<p>(<b>a</b>) Brightfield image of an iPSC-CM showing the AFM cantilever (black shadow). The yellow grid superimposed on the cell shows the range of the dwell map. (<b>b</b>) Dwell map showing contraction forces of a single iPSC-CM at various points on the grid. (<b>c</b>) Dwell map showing Young's modulus of a single iPSC-CM at various points on the grid. The periphery of the cell had higher contraction forces and elasticity compared to the central areas. (<b>d</b>) Beating force and Young's modulus (local elasticity) measurements were obtained from dwell mapping iPSC-CM derived from either a healthy subject (red) or from a subject with dilated cardiomyopathy (DCM, blue). Single points on the plot correspond to beat force and elasticity measured at each grid points of the dwell map. Points where no contraction force was measured (e.g., on the glass slide surrounding the cell) are not shown. The contour plot (middle) represents the probability distribution of dwell mapped points in the Young's modulus vs. beating force coordinate system. The contours show that beats measured from most portions of the healthy iPSC-CM fall in a region of moderate elasticity (50 – 5 kPa) and strong force (∼1 nN), whereas some points of the dwell map of DCM iPSC-CM showed comparatively lower beat forces and lower elasticity. Corresponding histograms that flank the contour plot are the distributions of beat force (above the contour plot) and elasticity (left of the contour plot), respectively.