Oxygen consumption of individual bovine embryos was noninvasively quantified by scanning electrochemical microscopy (SECM). A probe microelectrode was used to scan near a single embryo surface in a culture medium to monitor the oxygen reduction current at 37℃, under a water-saturated atmosphere of 5% CO_(2) and 95% air. The oxygen concentration profiles near the embryos were in good agreement with the theoretical spherical diffusion. When an embryo reached the stage of a morula with a 74-μm radius on day 6 after in vitro fertilization, the oxygen concentration difference (ΔC) between the bulk solution and the morula surface was 6.90±1.35 μM. The oxygen consumption rate (F) of the single morula was estimated to be (1.40±0.27)×10~(-14) mol s~(-1). After the SECM measurement, the embryo was continuously cultured for another 2 days and grew to the stage of a blastocyst with a 100-μm radius. For the blastocyst, the ΔC values for the inner cell mass side and the trophoblast side were 16.40±1.83 and 9.14±1.68 μM, respectively. The oxygen consumption rate of the blastocyst was found to be in the range of (2.50±0.46)×10~(-14) mol s~(-1)展开▼
