Author(s)

Morteza Khalilian, Mojtaba Rezazadeh Valojerdi, Mehdi Navidbakhsh, Mahmoud Chizari, Poopak Eftekhari-Yazdi

Department of Anatomy, Faculty of Medical sciences, Tarbiat Modares University, Tehran, Iran.
Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, Academic Center for Education, Culture and Research (ACECR), Tehran, Iran.
Mechanical Engineering Department, Iran University of Science and Technology, Tehran, Iran.
School of Design and Engineering, Brunel University West London, London, UK.

The precise determination of zona pellucida (ZP) hardness is largely unknown due to the lack of appropriate measuring and modelling methods. In this study, we have used experimental and theoretical models to describe the mechanical behavior of a single oocyte cell to improve the assisted reproductive technology (ART) outcomes by assessing oocyte/embryo quality. This paper presents the development of: i) a microinjection model to estimate the force of ZP penetration, ii) a micropipette aspiration model to determine the corresponding hardness, and iii) an experimental procedure to generate the required data for these two models. Our results show that the estimated penetration force provides a performance target for the penetration process during intracytoplasmic sperm injection (ICSI), while the estimated corresponding hardness serves as an indicator of the extent of deformation sustained by the oocyte prior to penetration. Evaluation of these results shows that a routine assessment of ZP hardness under microinjection would allow for the identification of certain oocyte pools for which further manipulation is recommended in order to improve injection, hatching and finally ART outcomes.

Human Oocyte; Human Embryo; Intracytoplasmic Sperm Injection; Zona Pellucida Hardness

Khalilian, M. , Valojerdi, M. , Navidbakhsh, M. , Chizari, M. and Eftekhari-Yazdi, P. (2013) Estimating zona pellucida hardness under microinjection to assess oocyte/embryo quality: Analytical and experimental studies. Advances in Bioscience and Biotechnology, 4, 679-688. doi: 10.4236/abb.2013.45089.