Global cytoskeleton reorganization is well-recognized when cells are exposed to distinct
mechanical stimuli, but the localized responses at a specified region of a cell are
still unclear. In this work, we mapped the cell-surface mechanical property of single
cells in situ before and after static point loading these cells using atomic force
microscopy in PeakForce-Quantitative Nano Mechanics mode. Cell-surface stiffness was
elevated at a maximum of 1.35-fold at the vicinity of loading site, indicating an
enhanced structural protection of the cortex to the cell. Mechanical modeling also
elucidated the structural protection from the stiffened cell cortex, in which 9–15%
and 10–19% decrease of maximum stress and strain of the nucleus were obtained. Furthermore,
the flat-ended atomic force microscopy probes were used to capture cytoskeleton reorganization
after point loading quantitatively, revealing that the larger the applied force and
the longer the loading time are, the more pronounced cytoskeleton reorganization is.
Also, point loading using a microneedle combined with real-time confocal microscopy
uncovered the fast dynamics of actin cytoskeleton reorganization for actin-stained
live cells after point loading (<10 s). These results furthered the understandings
in the transmission of localized mechanical forces into an adherent cell.