Evaluating the nucleus effect on the dynamic indentation behavior of cells

Area of Science:

• Biophysics
• Cell Mechanics
• Biomaterials Science

Background:

• Cell mechanical properties are crucial for biological functions.
• The nucleus significantly influences cell mechanical behavior.
• Accurate modeling of cell mechanics is essential for understanding cellular processes.

Purpose of the Study:

• To investigate the effect of the nucleus on cell mechanical behavior.
• To evaluate the accuracy of routine analysis methods in cell indentation studies.
• To develop a more accurate model for cell mechanical response.

Main Methods:

• Utilized a "two-component" cell model incorporating cytoplasm and nucleus.
• Employed a semi-empirical method based on fitting quasi-static indentation simulation results.
• Analyzed dynamic indentation response under a spherical tip.

Main Results:

• Routine analysis significantly overestimated the nucleus's effect on cell indentation.
• Hertz contact radius and substrate stiffening effects were stronger in the two-component model.
• Inaccuracy increased with nucleus-to-cytoplasm modulus ratio and nuclear volume fraction.

Conclusions:

• Standard "routine analysis" is insufficient for accurately determining nuclear influence on cell mechanics.
• The two-component model provides a more reliable framework for cell mechanical studies.
• Indentation analysis shows low sensitivity to geometrical parameters, allowing for reasonable assumptions.