Characterizing Mammalian Cell Shear Sensitivity to Improve Cell Culture Bioreactor Efficiency

Large scale bioreactors are used by the Biotechnology Industry for the production of therapeutic proteins. Bioreactors incorporate gas sparging to provide oxygen requirements for cell cultures, and facilitate mixing via an impeller. Agitation from sparging generates bubbles, which can damage cell cultures at the media/air interface within the culture broth and at the interface of the culture broth and tank headspace. Cell damage can impact VCD (viable cell density) and Culture Viability. To mitigate these challenges, Nonionic surfactants are included within the cell culture media. Specifically, surfactants known as Poloxamer, were evaluated in this study. Poloxamers allow for hydrophobic interactions with cell membranes, and hydrophilic interactions which sterically hinder cell-bubble attachment. This disruption of cell-bubble attachment reduces cell death in heads of foam. These interactions reduce cell damage to improve bioreactor performance. Characterization of Poloxamer effectiveness at protecting cell cultures during bioreactor operations can provide significant benefits to the manufacturing of therapeutic proteins. To evaluate the effectiveness of Poloxamer, a motorized cylindrical impeller was used to shear cells in a media solution containing Poloxamer. Experiments were designed and executed to investigate Poloxamer concentration, shear rate (RPM), and culture viability. Samples were analyzed via trypan blue dye exclusion to measure VCD and culture viability. Results from this study demonstrate a reliable method to quantify cell shear sensitivity in the presence of different Poloxamers