Time-Lapse Mechanical Characterization of Zona Pellucida Using a Cell Carrier Chip

The aim of this paper is to measure the changes in the mechanical characteristics of the zona pellucida (ZP) of an oocyte over time. To measure the mechanical characteristics such as Young's modulus during cultivation, it is necessary to achieve the cultivation and the measurement of the mechanical characteristics of target oocytes. Generally, measurement systems are constructed on a microscope for observing the deformation of the oocytes, but it is difficult to integrate such a system with a conventional incubator. Therefore, we propose a cell carrier chip for the time-lapse mechanical characterization. The cell carrier chip has a probe as well as a force sensor to measure the mechanical characteristics of the ZP. In addition, the chip enables us to carry the target oocyte from the measurement system to the incubator. To calculate the Young's modulus of the ZP, we used an elastic spherical shell model and measured the Young's modulus of the ZP of cryopreserved oocytes at 0.5, 1, 2, 3, 4, 5, and 6 h after being thawed. The result indicates that the Young's modulus of the ZP tends to increase with the cultivation time. [2017-0133]