Assay Requirements for Cell Culture Process Development
Initially, cell culture process development efforts were focused solely on maximizing the amount, or titer, of desired product. This chapter provides an overview of the assays most useful for achieving maximum production of high-quality products. Once a suitable assay of cell lysis is developed, it can be used for evaluation of culture conditions, including medium composition, reactor geometry, and time of harvest. The effect of product accumulation on cell health may also be investigated. Two-dimensional (2D) electrophoresis is a powerful technique for monitoring the aspects of cell health. Using different methods of detection, electrophoresis can be performed either directly on culture fluid or on purified proteins. Electrophoresis in the presence of the ionic detergent Sodium Dodecyl Sulfate (SDS) is probably the most common method of protein analysis. Isoelectric focusing (IEF) provides complementary information to SDS-PAGE. Capillary electrophoresis is really related to both chromatography and electrophoresis.