Mouse Oocyte Characterization by Electrical Impedance Spectroscopy.

Artificial fertilization depends on the oocyte quality, especially on the zona pellucida. This gelatinous outer layer becomes soft before and hardens after sperm penetration. Here, we propose a setup that characterizes the stiffness of the zona pellucida of mouse oocytes by electrical impedance spectroscopy. Single oocytes are hydrodynamically trapped at an aperture, which is located between two ring-shaped electrodes. By applying weak negative pressures to the cell trap, the electrical impedance correlates with the stiffness of the zona pellucida.