This is a small (or micro) example of natural selection!
When I culture blood-isolated primary monocytes, or the macrophages derived from them, I add 10% heat inactivated F.B.S and 1% P.S. to the R.P.M.I. media. Heat inactivated serum is used when working with immune cells and is prepared by heating the F.B.S. at 56°C for 30 minutes. This is done to inactivate and denature proteins in the serum. Denatured proteins lose function, and the proteins in the serum will not interact with the cells, bind to receptors or cause immune responses such as inflammation, all of which can negatively impact experiments.
There are a lot of other components that can be added into cell culture media depending on the type of cell or cellular response of interest. These factors include minerals, sugars, salts and buffers (to control pH... you’ll learn all about this in AP Chemistry!), antibiotics and hormones. I often differentiate, or transform, human-derived monocytes (immune cells found in the blood) into macrophages (immune cells that have traveled into tissue) through the addition of cytokines in the media. Cytokines are small signaling proteins that interact with immune cells, aiding in cell growth and immune responses.
When cells are cultured, they are typically grown in plates, flasks, or petri dishes. When growing cells over a long period of time in 2.D, I use a flask designed for adherent cell culture. This means that the cells will attach to the bottom of the flask and can be easily monitored. After cells are cultured in a flask, I passage them as soon as they reach 80 - 90% “confluency” or cover 80 - 90% of the bottom of the flask. Cell passaging is the act of washing, detaching and reseeding the cells.
