When i incubate my mammalian cells

[sotellme]

how should the lid be when i incubate my cells in:

1. multiwells: should i tilt the lid so that half of the plate is covered and half is exposed directly to air in the incubator? or should i just have the lid on so the whole plate is covered?

2. culture flask: should the lid be loosened (contamination risk)? or should i tie it completely (my cells can not get air )?

3. dish: should i only cover half of the dish? in this way half is covered and half is exposed directly to air in the incubator? or should i just have the lid on so the whole dish is covered?

thank you.

 

[DocToxyn]

For the multiwells, place the lid fully on the plate, the same goes for petri dishes. There will be too much evaporation with the lid skewed. Even with the lid on there will be plenty of air circulation, especially in the wells around the periphery of the plate. I have run across certain endpoints that are sensitive to this and an "edge effect" can be found if that data is examined correctly. I know certain labs that use 48-well formats and fill all the outer wells with PBS to eliminate such effects, I also use this technique for culturing of fetal thymus on porous membrane inserts, these can dry out very rapidly since the tissue is kept at the air-medium interface and keeping them in the outer wells is bad news.
When using culture flasks, or T-flasks, twist the cap so it is loose, but not so that it will potentially fall of when transporting the flasks (I usually tighten then caps before puling the flasks from the incubator anyway, but other people may bump them loose in a crowded incubator). Evaporative loss is less of an issue in this situation since there is less "exposure" to the incubator air and typically you're growing cells for later plating and not collecting samples directly from these flasks.