Atomic force microscopy probing for biomechanical characterization of living cells

The mechanical characterization of cells is important in understanding cellular behavior. A micro-robotic system such as atomic force microscopy (AFM) can be adapted to measure the mechanical behaviors of cells due to its high spatial resolution and high sensitivity. AFM probing experiments on cells were performed with conical tips and sphere-particle-attached tips; the results were analyzed to characterize the mechanical properties of cells. We developed novel finite element (FE) models that include the topological information of cells and AFM tips. We applied these models and a conventional linear elastic model, the Hertz-Sneddon model, to the cell response analysis. Our analysis showed that the conventional linear elastic model has limitations in analyzing large deformations resulting from the substrate. The FE model can accurately estimate the mechanical properties of cells with property coherences, regardless of the geometric effects. Our analysis results can be used to understand the mechanism of how a disease process affects the mechanical properties of cells as well as distinguishing special types of diseases.