Companies formulate DMEM always with 3.7g/L of sodium bicarbonate. But majority of researchers use only 5% CO2 incubators, which is ideal for media with 1.5-2.2g/L of sodium bicarbonate. 3.7g/L of NaHCO3 requires 10% CO2. So, while most of us use only 5% CO2 incubators and everyone knows this, companies must have a good reason for insisting on 3.7g/L. Do you have an idea on this? Does DMEM have to contain 3.7g/L NaHCO3 for some reason?
People in my lab also use DMEM but they didn't know DMEM requires 10% CO2. I let them know this but they are not willing to change their culture conditions as all of their experiments have been done in 5% CO2 all the time. So I decided to buy DMEM with lower NaHCO3 concentration. I found one from ATCC (1.5g/L), but they have only high glucose DMEM (I use low glucose DMEM). I found powder forms where I can add the desired amount of NaHCO3 but I don't want to spend time on preparation, pH adjustments and sterility issues. Do you have a suggestion about what to do? Should I just ignore these questions in my mind and keep doing what many researchers have been doing wrongly (i.e. using DMEM with 5% CO2)?
Thanks in advance for your replies.
Edited by mevcit, 14 April 2015 - 04:32 AM.