Revealing the molecular events of neuronal growth is critical to obtaining a deeper understanding of nervous system development, neural injury response, and neural tissue engineering. Central to this is the need to understand the mechanical interactions between the cytoskeleton and the cell membrane, and how these interactions affect the overall growth mechanics of neurons. Using finite element analysis, the normal contact stress produced by a protein filament that is acting against a deformable membrane was modeled, and the deformation, stress, and strain were computed for the membrane. The model predicts that a single actin filament is able to produce a normal contact stress on the cell membrane that is sufficient to cause membrane deformation, but not rupture.During single-cell and single-organelle injection, damage to the cell will often result. By first determining the mechanical properties of the cell, and then quantifying the amount of force that is required for cell membrane puncture, the use of excessive force during injection can be avoided. This will serve to minimize the damage done to the cell during these procedures. Using micropipette-deformation-based methods and an imageprocessing based algorithm for measuring deformation, the mechanical roperties of spherical DOPC:DOPS liposomes, model cells, were measured. From these values, the forces that injection pipettes of various sizes exert onto liposomes during manipulation were determined. Forces ranged from ~1 - 6 pN, and these forces increased as the pipette size decreased.Ph.D., Mechanical Engineering -- Drexel University, 200
