Precise determination of elastic modulus of cell using conical AFM probe.
The Sneddon formula is conventionally used to calculate the elastic modulus of cell based on atomic force microscope (AFM) experiments. Owing to the disobedience of the formula assumptions, errors exist. Here, the ABAQUS for finite element modeling and analysis was used to simulate the process of compression of cell with a AFM conical probe. It was found that the relative error ranges from 0.094 to 1.455 folds, depending on half angle of the cone, curvature radius at the tip of the cone and the compression depth. By fitting the error data, we proposed a correction factor, which can be multiplied by the Sneddon formula to get a modified formula, providing the more accurate elastic modulus of cell. The experimentally measured elastic moduli of cell and hydrogel are in good agreement with the values obtained using the modified formula.