Should I always split my cells at their mid log phase? Or does it only matter at transfection? How do I know that my cells are in the mid log phase or not too long in the plateau?
cells that are up to 50 % confluency and less than 80% are in their mid log phase
Where should I prepare the media? In the laminar flow hood or on an opened table (risks for contamination?) ?
media must be prepared in the laminar flow
If medium with serum contains trypsin inhibitor. What should I use to dislodge my cells?
You should wash your cells twice with PBS. you may dilute trypsin in PBS. Inactivate the trypsin by adding medium.
Should I always have HCO3- in the medium and what for?
usually, cells are in 5%CO2 air. This ensure a combination with the media to automatically form HCO3-. This ions give the pH stability and it's essential (but automatic) to have it in the media