An atomic-force-microscopy study of the structure of surface layers of intact fibroblasts

Intact embryonic fibroblasts on a collagen-treated substrate have been studied by atomic-force microscopy (AFM) using probes of two types: (i) standard probes with tip curvature radii of 2–10 nm and (ii) special probes with a calibrated 325-nm SiO 2 ball radius at the tip apex. It is established that, irrespective of probe type, the average maximum fibroblast height is on a level of ~1.7 μm and the average stiffness of the probe–cell contact amounts to ~16.5 mN/m. The obtained AFM data reveal a peculiarity of the fibroblast structure, whereby its external layers move as a rigid shell relative to the interior and can be pressed inside to a depth dependent on the load only.