Depth-sensing analysis of cytoskeleton organization based on AFM data

Abstract

Atomic force microscopy is a common technique used to determine the elastic properties of living cells. It furnishes the relative Young's modulus, which is typically determined for indentation depths within the range 300-500 nm. Here, we present the results of depth-sensing analysis of the mechanical properties of living fibroblasts measured under physiological conditions. Distributions of the Young's moduli were obtained for all studied cells and for every cell. The results show that for small indentation depths, histograms of the relative values of the Young's modulus described the regions rich in the network of actin filaments. For large indentation depths, the overall stiffness of a whole cell was obtained, which was accompanied by a decrease of the modulus value. In conclusion, the results enable us to describe the non-homogeneity of the cell cytoskeleton, particularly, its contribution linked to actin filaments located beneath the cell membrane. Preliminary results showing a potential application to improve the detection of cancerous cells, have been presented for melanoma cell lines.

De-adhesion dynamics of melanoma cells from brain endothelial layer

“…Both A2058 and A375 cells show similar adhesive properties to brain endothelial cells with similar junction damaging potential in static models (28,29). Pogoda et al denotes A375 cells as highly invasive (30) and compares its elasticity to WM35 emphasizing that the former has lower elastic modulus (which correlates well with our results). The above mentioned studies deal with the total transmigration process of the melanoma cells across the endothelium, which includes but is not restricted to initial affinity dynamics of firm adhesion establishment.…”

Morphological and Mechanical Properties of Osteosarcoma Microenvironment Cells Explored by Atomic Force Microscopy

“…In this study, the Young's modulus of the cells was calculated at a 200-nm indentation depth, which has been reported to be an abundant of actin network. 19 The reduced Young's modulus Er correlates with the Young's modulus of sample Es, and is given by:…”

Measuring the Stiffness of <em>Ex Vivo</em> Mouse Aortas Using Atomic Force Microscopy

“…This indentation depth would correlate with the top layer of endothelial cells located in the intima 21 . To probe the mechanics of the sub-endothelial layers of arterial samples, larger colloidal probes (10 -20 µm in diameter) could be used for indentation and changes in the calculated stiffness with indentation depth could be determined 22,23 . Also, since biological samples are usually viscoelastic rather than purely elastic, stress relaxation measurements (monitoring the decay in applied force at a constant indentation depth) could be used to determine the viscous component of arterial mechanical properties 24,25 .…”