Mechanical Measurements of Cells Using AFM: 3D or 2D Physics?

Abstract

In AFM force spectroscopy, curves of the force against the indentation depth provide mechanical insight about the sample The approach part of the curves provides information on the sample elasticity. The derivative of the curve is affected by the resistance of the sample to the applied force-the lower is the slope, the higher is the elasticity. The elasticity parameter obtained from such analysis is often regarded as the Young's modulus, suggesting that it can represent the local rigidity of the sample. This derivation is valid when the sample behaves in an elastic manner. In the case of cells, it can be a reasonable assumption provided that the experimental conditions are properly tuned. The elastic moduli are obtained by fitting the force-indentation plots to appropriate physical models. The theories used for cell measurements analysis are based on 3D physics. Contact mechanics theories, which are the default models of AFM analysis software, are the most common (Kilpatrick et al.,

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