Determination of pyruvate and lactate as potential biomarkers of embryo viability in assisted reproduction by capillary electrophoresis with contactless conductivity detection

Human-assisted reproduction is increasing in importance due to the constantly rising number of couples suffering from infertility issue. A key step in in vitro fertilization is the proper assessment of embryo viability in order to select the embryo with the highest likelihood of resulting in a pregnancy. This study proposes a method based on CE with contactless conductivity detection for the determination of pyruvate and lactate in spent culture media used in human-assisted reproduction. A fused-silica capillary of 64.0 cm total length and 50 mu m inner diameter was used. The inner capillary wall was modified by the coating of successive layers of the ionic polymers polybrene and dextran sulfate to reverse EOF. The BGE was composed of 10 mM MES/lithium hydroxide, pH 6.50. The sample was injected by pressure 50 mbar for 18 s, separation voltage was set to -24 kV, and capillary temperature to 15 degrees C. The presented method requires only 2 mu L of the culture medium, with LODs for pyruvate and lactate of 0.03 and 0.02 mu M, respectively. The results demonstrated the method's suitability for the analysis of spent culture media to support embryo viability assessment by light microscopy, providing information about key metabolites of the energy metabolism of a developing embryo.