细胞伪足断裂的力学行为和微观机制分析

Objective To elucidate the mechanisms of interface disruption between the actin filament and membrane of the cell pseudopodium that occurs during the breakage of the pseudopodium. Methods Time-lapse images of the behavior of actin filaments and membranes during the rupture process of cell pseudopodia were captured using the confocal microscopy. A theoretical model of the fracture of a cylindrical interface was developed to analyze the interface damage between the actin filament and the membrane during the breakage of the cell pseudopodium. Molecular dynamics simulations were employed to simulate the breaking process of the cell pseudopodium for comparison with the theoretical results. A finite element model considering the coupling of the tensile and torsional deformation of actin filaments was developed to simulate the torsional deformation of actin filaments under tension, both in the presence and absence of a membrane. Results The theoretical results indicated an exponential relationship between the critical load for the broken interface and crack length. The critical load increased with the interfacial strength. The effect of the fiber diameter on the critical load depended on the crack length, exhibiting different effects for small and large crack lengths. Finite element analysis suggested that the membrane substantially constrained torsional movement when the actin filament was extended. Conclusions This study revealed the breaking process of cell pseudopodia and the mechanical aspects underlying the disruption of the interface between the actin filament and the membrane. These results provide theoretical support for exploring cellular behaviors associated with pseudopodium breakage, such as the release of extracellular vesicles.