In the 1960’s, several researchers determined that only cells capable of proliferation were able to form colonies. Therefore, counting the colony forming units could be a good surrogate to counting cells. Semi-solid methylcellulose has become a polymer of choice for colony forming cell assays (CFC).
The final concentration of methylcellulose used in the assays is typically 1-1.5%, allowing cells to grow while discouraging cell migration and encouraging colony formation. Nutrients, proteins and growth factors, or serum-free alternatives, are added as well.
Cell culture media
The biopharmaceutical market continues to grow at a rapid pace, fueling the need for cells to produce proteins, cell, or gene therapies. Cell production yields greatly impact the production time and cost of biopharmaceutical therapies and are still -in general- considered a bottleneck to further scale up and scale-out approaches. Cell culture media have been significantly optimized over the last years to improve production yields. While traditional media often included media from animal and human origins, the industry is evolving towards current expectations for chemically, defined and serum/xeno-free media.