A dual near-infrared and dielectric spectroscopies strategy to monitor populations of Chinese hamster ovary cells in bioreactor

Objective

to develop a new strategy combining near-infrared (NIR) and dielectric spectroscopies for real-time monitoring and in-depth characterizing populations of Chinese hamster ovary cells throughout cultures performed in bioreactors.

Results

Spectral data processing was based on off-line analyses of the cells, including trypan blue exclusion method, and lactate dehydrogenase activity (LDH). Viable cell density showed a linear correlation with permittivity up to 6 × 10⁶ cells ml^?1, while a logarithmic correlation was found between non-lysed dead cell density and conductivity up to 10⁷ cells ml^?1. Additionally, partial least square technique was used to develop a calibration model of the supernatant LDH activity based on online NIR spectra with a RMSEC of 55 U l^?1. Considering the LDH content of viable cells measured to be 110 U per 10⁹ cells, the lysed dead cell density could be then estimated. These calibration models provided real-time prediction accuracy (R² ≥ 0.95) for the three types of cell populations.

Conclusion

The high potential of a dual spectroscopy strategy to enhance the online bioprocesses characterization is demonstrated since it allows the simultaneous determination of viable, dead and lysed cell populations in real time.