MODEL-BASED SIMULATION OF THE CELL PENETRATION PROCESS WITH THE APPLICATION TO

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Intracytoplasmic sperm injection (ICSI) is a common in vitro fertilization technique in which a selected spermatozoon is directly injected into a mature oocyte. Many ICSI experiments, however, show a pronounced variation in survival, fertilization and pregnancy rates due to the injury of eggs induced by the external mechanical forces. Therefore, a fundamental study of the mechanical response of eggs in ICSI is required to lessen the injury as much as possible so that the ICSI success rate could be improved. It is proposed that the material point method (MPM) be employed to simulate the ICSI process involving contact, impact, penetration, and solid-fluid interactions. As one of the innovative spatial discretization procedures, the MPM discretizes the continuum body with a collection of material particles and solves the equations of motion on a computational background mesh. By taking advantage of both the Eulerian and Lagrangian methods, the MPM is suitable for those problems involving large deformations, multiple material phases, as well as material separation and moving discontinuity. The proposed research tasks consist of: (1) development of a three-dimensional MPM program for simulating cell membranes and fluids, (2) study of the effects of different material properties and external forces on the mechanical response of eggs in ICSI, and (3) investigation of the convergence and stability of the MPM modeling of the ICSI process.