Hi,
This is actually just a general question out of curiosity. I have tried transfection using PEI both in suspension and attached cells, with and without antibiotic before and I don't see any difference. I understand that in lipid-based transfection, antibiotic can hinder the complex formation of lipid and DNA, but because PEI works differently I don't see why it is still advisable to use antibiotic-free media?
In our lab but we even don't change media in culture vessel for lipofectamine transfection and it still work perfectly, as long as we perform the DNA-lipofectamine complex formation in OPTIMEM first. It is also easier because we don't need to wash or change media prior to transfection.
Any other opinion?
Dear Lia
my experience, limited to expifectamine and Expi293 cells is that also in this case the presence of pen/strep antibiotic mix do not affect in any way the trasfection results.
I compared the yields in terms of recombinant protein expression in the surnatant for some different protein target in presence of pen/strep at 3 different dilutuons vs no pen strep and we do not observe significant differences. Sincerelly i never tried to do not use the optimem, also because it is cheaper than expi293 expression medium.
ciao
Manuele
Hi Lia,
As I understand it, the thinking is that with reagents that permeabilise the cell membrane (as PEI does), you're equalising the concentration between the media (high concentration of antibiotics) and the cytosol (lower concentration of antibiotics) since the cell can no longer regulate import of the antibiotic. This may prove detrimental to the cell or interfere with your experiment.
Best Regards
Dear Manuele Martinelli
Thank you very much for your input. It's good to hear that you also have no problems in your experiment. For me personally, when transfecting Hek293F (suspension) cells, I even don't use OPTIMEM. Just add DNA and PEI in 1xPBS and it still works fine.
Have a good day at work!
Lia
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