Oxygen consumption of mammalian embryos and oocytes monitored by scanning electrochemical microscopy

Scanning electrochemical Microscopy (SECM) has been used to noninvasively characterize oxygen consumption rate of single mammalian embryos and oocytes under physiological condition in culure medium at 37 °C. Local oxygen concentration profile near the embryo sample was monitored by scanning with a Pt microelectrode probe, and then mass transfer rate for oxygen has been estimated based on spherical diffusion theory. A bovine embryo at two-cell stage was located in either a conventional culture dish or a cone-shaped microwell and compared the differences in concentration profile and diffusion behavior. We found that the cone-shaped microwell functions to amplify the oxygen concentration difference between the sample surface and the bulk. Further more, a measuring plate equipped with the cone-shaped six-microwells was developed to easily handle many embryos in a short time. The respiration activities significantly increased with the embryo development for both bovine and mouse.