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

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 卵胞浆内单精子注射（ICSI）是一种常见的体外受精技术，其中将选定的精子直接注射到成熟的卵母细胞中。然而，许多ICSI实验显示，由于外部机械力引起的卵子损伤，存活率、受精率和妊娠率存在显著差异。因此，有必要对ICSI中卵子的力学反应进行基础研究，以尽可能减少损伤，提高ICSI的成功率。建议采用物质点法（MPM）模拟ICSI过程，包括接触、撞击、渗透和固液相互作用。作为一种创新的空间离散化方法，MPM离散的连续体与收集的材料颗粒和解决的运动方程的计算背景网格。MPM方法综合了欧拉法和拉格朗日法的优点，适用于大变形、多相、材料分离和运动不连续等问题。本论文的主要研究内容包括：（1）开发一个三维MPM程序，用于模拟细胞膜和细胞液;（2）研究不同材料特性和外力对卵胞浆内注射过程中卵子力学响应的影响;（3）研究MPM模型的收敛性和稳定性。

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.