Influence of semiflexible structural features of actin cytoskeleton on cell stiffness based on actin microstructural modeling.

A new actin cytoskeleton microstructural model based on the semiflexible polymer nature of the actin filament is proposed. The relationship between the stretching force and the mechanical properties of cells was examined. Experiments on deforming hematopoietic cells with distinct primitiveness from normal and leukemic sources were conducted via optical tweezer manipulation at single-cell level. The modeling results were demonstrated to be in good agreement with the experimental data. We characterized how the structural properties of the actin cytoskeleton, such as prestress, density of cross-links, and actin concentration, affect the mechanical behavior of cells based on the proposed model. Increasing prestress, actin concentration, and density of cross-links reduced cell deformation, and the cell also exhibited strain stiffening behavior with an increase in the stretching force. Compared with existing models, the proposed model exhibits a distinct feature in probing the influence of semiflexible polymer nature of the actin filament on cell mechanical behavior.