Non-invasive and time-resolved measurement of the respiration activity of Chinese hamster ovary cells enables prediction of key culture parameters in shake flasks.

Abstract

Shake flasks are frequently used for mammalian cell suspension cultures. For process development and routine culture monitoring, information on culture behavior is needed early on. Here, cell-specific oxygen uptake rates (qO2 ) of two CHO cell lines were determined from shake flask experiments by simultaneous measurement of oxygen transfer rates (OTR) and viable cell concentrations (VCC). For cell line one, qO2 decreased from 2.38·10-10 to 1.02·10-10 mmol cell-1 h-1 during batch growth. For cell line two, qO2 was constant (1.90·10-10 mmol h-1 ). Determined qO2 values were used to calculate the VCC from OTR data. Cumulated oxygen consumption and glucose consumption were correlated for both cell lines and enabled calculation of glucose concentrations from OTR data. IgG producing cell line one had an oxygen demand of ∼15 mmoloxygen gglucose -1 , cell line two consumed ∼5 mmoloxygen gglucose -1 . The established correlations for determination of VCC and glucose were successfully transferred to subsequent cultivations for both cell lines. Combined measurement of the OTR and the carbon dioxide transfer rate enabled quantitative determination of the lactate concentration (production and consumption) without sampling. Taken together, non-invasive measurement of the respiration activity enabled time-resolved determination of key culture parameters for increased process understanding in shake flasks.