pH Measurements & CO2 Concentrations:
Due to the high cell densities typically achieved in FibraCel culture, the pH levels in the medium may fluctuate in the later stages of cell growth.
Adjust the culture medium pH to a range of between 7.2 to 7.4 for mammalian cell culture, 6.2 to 6.4 for Sf-9 insect cells, and 6.4 to 6.5 for Hi-5 cells.
When growing mammalian cell cultures, a pH level above 7.6 may slow attachment of your cells to the disks. If the culture medium contains 2.2 g/L NaHCO3, set the CO2 to 5%. If pH is below normal range, adjust the CO2 concentration to 0, and/or increase the NaHCO3 concentration to 3.7 g/L. Culture medium containing 25 mM HEPES can also stabilize the pH during culture.
In insect cultures, when the pH is below 6.0, add 1M of Bis-Tris to increase the pH to 6.5. Increasing the Up/Down Speed and Bottom Hold Time will help to expel CO2, reduce lactate production, and thus further stabilize pH in culture medium.
Measure the pH regularly, and adjust the CO2 concentration accordingly in the incubator.
The medium consumption is process dependent. Expect to use 1 to 3 L of media for virus production in semibatch culture. In processes where you are continuously collecting conditioned culture medium for secreted protein production, you may use 5 to 10 L of media to extend the culture to about 15 days.
Replenish or modify the culture media as necessary:
Glucose Concentration - Change the medium when
the glucose concentration falls below 1.0 ~ 1.5 g/L
(initial glucose concentration should be > 3.5