Figure 1
Defining contact conditions during compression of the nucleus. (a) Left: top-view microscopy image of the adhered nucleus. Right: the tip-less cantilever is brought down to compress the nucleus. (b) Left: side-view projection reconstructed from a stack of fluorescent microscopy images. The adhesive contact between nucleus and supporting surface is clearly visible. Right: the same nucleus under compression after the cantilever has been brought down. (c) The measured adhesive contact radii of five nuclei of different sizes (red). The calculated radii based on the height/width ratio agree within ~15% (blue). (d) Force versus indentation plots for comparing the calculated compression of a sphere with E = 2 kPa, assuming different contact conditions. Shown are two analytical solutions: the Hertzian contact (black dash line) and an extension of this model that includes the adhesive contact42 (grey dash line). The other two curves are from FEA and show the compression of a sphere with adhesive contact with a parallel (blue solid line) and tilted cantilever (red/orange solid line).
