From Rheology to Elasticity: How Can We Capture the Dynamical Properties of Cells?

Abstract

Atomic force microscopy has been introduced in the late 1980's in cellular biology to probe the mechanical response of living systems with a nanoscale resolution. However in traditional force-indentation curves obtained such a tool, the discrimination of elastic, viscous and dynamical aspects of a cell response under mechanical stress is very difficult, because it assumes that we have already designed a correct model to capture this response. Actually the response of a cell span different scales in space and in time. We propose here to revisit the interpretation of force-indentation curves without any a priori model to capture the temporal evolution of the shear modulus of living cells and compare this response to simple visco-elastic models. We show that using multi-scale analyzing tools such as wavelet transforms offers the possibility to survey in real time the different response modes of a cell during an indentation experiment.Because cells are also very different from one tissues to another one, we take cells with different adherence for this discussion; namely strongly adherent cells such a fibroblasts or myoblasts, circulating cells such as blood cells and intermediate cells that have also a very rich metabolic role such as hepatocytes.I acknowledge my collaborators in this work: namely Alain Arneodo, Benjamin Audit, Lotfi Berguiga, Elise Boyer-Provera, Simona Diguini, Guenola Drillon, Bastien Laperrousaz, Mael Le Berre, Veronique Maguer Satta, Cristina Martinez-Torres, Mathieu Piel, Laurent Schaeffer and Laura Streppa.