Ferruccio Messi, Ph.D., CEO of Cell Culture Technologies, another speaker at the Cambridge event, is a huge advocate of what he calls minimal cell culture media. Minimal media contain only water and small molecule chemicals with Chemical Abstract Services or European Inventory of Existing Commercial Chemical Substances numbers—no animal-derived sera, extracts, peptones, hydrolysates, or other undefined substances. “We only use compounds with a defined chemical identity,” said Dr. Messi.
According to Dr. Messi, 15 companies have performed “remarkable work” on the cultivation of CHO cells in minimal media. He described one line, the CHO-easyC (derived from CHO-K1), as “one of the most promising host cell lines for development of next-generation bioprocesses.
“Many people talk about chemically defined media, but when you try to go beyond that definition you realize that chemically defined means everything and therefore nothing. People are using chemically defined lipid mixtures, and the user doesn’t know what’s in there. In my presentation, I showed the complete composition of a minimal medium, and everybody knew what I was talking about.”
Even more than media that take half-measures to achieve chemical definition, minimal media replace all vestiges of black boxes and “fairy dust” from cell culture with hard science—only what cells actually need to thrive and produce.” The most obvious benefit is batch-to-batch consistency and the opportunity for science-based optimization—goals that can only be achieved when processors know precisely what media consist of. Minimal media are also less likely to require esoteric purification techniques and more readily satisfy regulators.
Processors add extracts, hydrolysates, and other ingredients, explained Dr. Messi, because their basal media are not optimized. “They didn’t fulfill the cell’s basic nutritional requirements, so they compensated by adding boosters. But you can easily grow any kind of cell in minimal media if you knew the identity of every molecule required by cells, and their proper balance.”
Cell Culture Technologies provides its expertise through long-standing collaborations with client companies. The average such relationship, which involves scientists from Dr. Messi’s company working at clients’ facilities, lasts 2.7 years. “It’s a lot more complex than filling a bottle with media and selling it,” Dr. Messi explained.