Highlights Review on magnetic field influence on industrial mammalian cells for biopharmaceutical production. Characteristics of magnetic field in the context of bioreactors. Different effects of magnetic field exposure on industrial mammalian cell lines.

Advantageous cultivation procedures for the Chinese hamster ovary (CHO) cells are necessary for the productive commercial production of biopharmaceuticals. A main challenge that needs to be addressed during the process development is the differences in each cell line requirements concerning the nutrients and feed strategies in order to achieve the desired growth characteristics. Therefore, within the current research, a naïve high cell density serum free suspension adapted CHO cell line was tested with glucose and glutamine rich feeds in fed-batch Erlenmeyer shake flask cultures. Glucose consumption rate was adjusted to develop the optimal feed strategies. Obtained results indicated that high glucose and l-glutamine feeding did not improve maximum viable cell density compared to the control samples. During the exponential phase, cell proliferation and viability of all feeds showed no statistically significant difference. Instead, the fed-batch processes tested led to statistically significant differences in viable cell density and cell viability during the decline phase, compared to control (batch) culture. The difference between glucose and glutamine feeding was indistinguishable, most probably due to the concentration imbalance with the rest of the nutrients in feed. The overall study presented a method to slow down the decrease in CHO cell proliferation and viability during the decline phase, instead of increasing the maximum cell density at the plateau phase. 

The lack of a sufficient research base is the reason for the ongoing discussion regarding the genotoxic effect of magnetic field (MF) exposure on mammalian cell cultures. Chinese hamster ovary (CHO) suspension-type cells, which are widely used for biopharmaceutical production, are potentially subjected to an increased MF when cultivated in bioreactors equipped with bottom-placed magnetically coupled stirring mechanisms. The main challenge for conducting research in this field remains the availability of a suitable experimental setup that generates an appropriate MF for the raised research question. In the present study, a simple and cost-effective experimental setup was developed that generated a static MF, similar to what has been modeled in large-scale bioreactors and, at the same time, was suitable for experimental cell cultivation in laboratory conditions. The measured maximum magnetic flux density to which the cells were exposed was 0.66 T. To assess the possible genotoxic effect, cells were continuously subcultivated in laboratory petri dishes for a period of 14 days, corresponding to a typical duration of a biopharmaceutical production process in a conventional fed-batch regime. The genotoxic effect was assessed using the cytokinesis-block micronucleus assay with fluorescent staining. Results showed that a 0.66-T static MF exposure had no significant long-term effect on cell viability and chromosomal damage but demonstrated a short-term effect on cell apoptosis. Significant increase in nuclear bud formation was observed. These findings may encourage other researchers in future studies investigating cellular responses to MF exposure and contribute relevant data for comparison.