We are looking to streamline our process development and scale up. Do you think it is possible to use a single media for cloning, seed train expansion and production, with just minor modifications at each step? We are trying to eliminate using different media for each step of the process. Ideally we would just have one media, but if that is not possible then it would be nice to have one base media with adding a few components to each step as necessary

Answer

You probably could use one medium if you choose the correct one. For cloning you want to start with as small a volume as possible and the medium should have B12 as one of its vitamins. As cells grow they transfer nutrients and growth factors back and forth across their membrane. If the volume of medium is so great that they can not get back what they need to survive because of dilution, the cells will go into apoptosis. Make sure your incubator is humidified as evaporation concentrates the salts and this is also deadly to the cell. For expansion take advantage of the good things in the conditioned medium and only remove about half of the volume and add back an equal volume of fresh medium until the cells are growing exponentialy. Protect your media from light degradation and control for ammonia production. To do this I would switch from glutamine (2.0 mM) to the dipeptide once the cells are expanding and as the cultures increase in concentration per unit volume, increase the concentration of glutamine dipeptide to 6.0 mM. Also be sure your medium has sodium pyruvate and the so-called non-essential amino acids. If your cells have been grown in the presence of pyruvate and you switch to a medium without pyruvate the cells will go into apoptosis. The other worry is lactate produced from glucose raising the osmolality. I would pick a medium with an osmolality between 270 and 290.