Development of Oxygen Consumption Analysis with an on-Chip Electrochemical Device and Simulation

The O₂ consumption rate of embryos has been attracting much attention as a key indicator of cell metabolisms and development. In this study, we propose an on-chip device that enables the accurate, easy, and noninvasive measurement of O₂ consumption rates of single embryos. Pt electrodes and micropits for embryo settlement were fabricated on Si chips via microfabrication techniques. The configuration of the device enables the detection of O₂ concentration profiles surrounding the embryos by settling embryos into the pits with a mouth pipet. Moreover, as the detection is based on an electrochemical method, the influence of O₂ consumption on the electrodes was also considered. By using a simulator (COMSOL Multiphysics), we estimated the O₂ concentration profiles in the device with and without the effects of the electrodes. Based on the simulation results, we developed a normalization process to calculate the precise O₂ consumption rate of the sample. Finally, using both the measurement system and the algorithm for the analysis, the respiratory activities of mouse embryos were successfully measured.