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

Background: 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.

Main methods and major results: 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 mmol_oxygen g_glucose ^-1 , cell line two consumed ∼5 mmol_oxygen g_glucose ^-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.

Conclusions and implications: Taken together, non-invasive measurement of the respiration activity enabled time-resolved determination of key culture parameters for increased process understanding in shake flasks.

Keywords: Chinese hamster ovary cells; carbon dioxide transfer rate; oxygen transfer rate; respiratory quotient; shake flasks.