The culture medium is a living environment for artificially simulating the growth of cells in vivo, and plays a key role in cell culture. 1. There is no certain standard for selecting a medium. A certain medium can be suitable for a variety of cells, and a certain cell can also be grown in different culture solutions. However, the medium used to establish a cell line should be the preferred medium for culturing such cells. You can refer to the reference or consult when purchasing a cell line. 2.1640 is indeed a very cheap medium and is also very useful. However, its buffering power is the weakest, so it sometimes affects the growth state of cells, especially in some laboratories that have long-term poor passage. Conditional still use DMEM medium. 3. Once serum and antibiotics have been added to the fresh medium, place in a 4 degree freezer. It should be used up within 2 to 3 weeks. Because some antibiotics and essential components in serum begin to degrade after thawing. After 2-3 weeks, the degradation is complete. 4. The pH of the medium increases parabolically as the amount of sodium bicarbonate increases. When sodium bicarbonate is added to a certain amount, the pH changes become smaller and smaller. The osmotic pressure of the medium increases linearly with the increase of the amount of sodium bicarbonate. The larger the amount of sodium bicarbonate, the higher the osmotic medium becomes, and the cells will dehydrate and shrink. (ATCC recommends that most cells add 1.5 g/L sodium bicarbonate) 5. Fetal bovine serum must be stored at –20 to -70 ° C. If stored at 4 ° C, it will degrade after 2 to 3 weeks. A 500 ml serum, 40 to 45 ml each, can be dispensed into a sterile 50 ml centrifuge tube. 6. The thawing of serum and the thawing of cells are the opposite: the faster the cells, the better; the slower the serum, the better. Serum thawing step: Take out the refrigerator at -20 ° C or –70 ° C, put it in the refrigerator at 4 ° C, let it cool for a day. 7. Imported fetal bovine serum generally does not require heat inactivation, as it will cause a significant increase in sediment and will affect serum quality. These precipitates are observed under a microscope, such as "small black spots", often mistaken for contamination of the serum. Wheat Seed,Winter Wheat Seed,Wheat Varieties,Organic Wheat Seeds XIKE AGRICULTURAL GROUP CO . .LTD. , https://www.laoseed.com